Baby Weight Length Percentile Calculator & Guide
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Baby Growth Percentile Calculator
Your Baby's Growth Percentiles
—
Percentiles are calculated using WHO (World Health Organization) growth standards, which compare your baby's measurements to those of other babies of the same age and sex. A percentile indicates that a baby's measurement is greater than or equal to that percentage of babies in the reference population.
Growth Chart: Weight and Length Percentiles Over Time (Illustrative)
Growth Data Comparison
| Metric |
Your Baby |
50th Percentile (Median) |
3rd Percentile |
97th Percentile |
| Weight (kg) |
— |
— |
— |
— |
| Length (cm) |
— |
— |
— |
— |
What is a Baby Weight Length Percentile Calculator?
A baby weight length percentile calculator is a tool designed to help parents, caregivers, and healthcare professionals assess a baby's growth by comparing their weight and length measurements against established growth charts. These charts, often based on data from organizations like the World Health Organization (WHO) or the Centers for Disease Control and Prevention (CDC), represent the typical growth patterns of healthy infants. The calculator takes your baby's age, sex, weight, and length as input and outputs their position on these growth charts, expressed as a percentile. This percentile indicates how your baby's measurements stack up against thousands of other babies of the same age and sex. For instance, if a baby is in the 75th percentile for weight, it means they weigh more than 75% of babies of the same age and sex, and less than 25%.
This tool is invaluable for monitoring a baby's development trajectory. It helps identify potential concerns early, such as being significantly underweight or overweight, or experiencing a growth spurt or slowdown. It's important to remember that percentiles are just one piece of the puzzle; a baby's overall health, feeding patterns, activity levels, and developmental milestones are equally crucial. A baby consistently tracking along a specific percentile curve is often considered healthy, even if that curve is high or low.
Who Should Use It?
- Parents and Guardians: To gain insights into their baby's growth and discuss concerns with pediatricians.
- Pediatricians and Healthcare Providers: To quickly assess a baby's growth status during check-ups and make informed clinical decisions.
- Lactation Consultants and Nutritionists: To evaluate feeding adequacy and nutritional status.
Common Misconceptions
- Misconception: Being in a low percentile (e.g., 5th) automatically means a baby is unhealthy or failing to thrive.
Reality: A baby can be perfectly healthy and thriving while consistently tracking along a lower percentile curve. The key is consistent growth.
- Misconception: Babies should always be aiming for the 50th percentile (the "average").
Reality: Every baby is unique. Growth patterns vary, and a baby's individual genetic potential and health status are more important than hitting a specific number.
- Misconception: A sudden jump or drop in percentile is always a cause for alarm.
Reality: While significant shifts warrant discussion with a doctor, minor fluctuations can occur. The overall trend and the baby's well-being are paramount.
Baby Weight Length Percentile Calculator Formula and Mathematical Explanation
The calculation of percentiles for baby growth is complex and relies on statistical models derived from extensive population data. These models, such as the WHO or CDC growth charts, are not simple linear formulas but rather intricate curves fitted to data points collected from a large sample of infants. They often use methods like the LMS (Lambda, Mu, Sigma) method to model the median (M), the coefficient of variation (S), and the skewness (L) of the distribution at each age.
For practical purposes within a calculator, we often use simplified approximations or look-up tables derived from these models. The core idea is to determine where a baby's measurement (weight, length, or weight-for-length) falls relative to the distribution of measurements for babies of the same age and sex.
Simplified Calculation Concept (Illustrative, not exact WHO/CDC):
While the exact WHO/CDC calculations involve complex statistical functions (like the generalized additive models for location, scale and shape – GAMLSS), a conceptual understanding involves comparing the baby's measurement to the mean and standard deviation of the reference population at that specific age and sex. The percentile is then derived from this comparison.
Weight Percentile: Compares the baby's weight to the weight distribution of babies of the same age and sex.
Length Percentile: Compares the baby's length to the length distribution of babies of the same age and sex.
Weight-for-Length Percentile: Compares the baby's weight relative to their length, irrespective of age (though age and sex are still factors in the underlying reference data). This is particularly useful for assessing thinness or fatness.
Variables Used in Growth Chart Models:
| Variable |
Meaning |
Unit |
Typical Range (Illustrative) |
| Age |
Age of the infant since birth |
Weeks |
0 – 104 (approx. 2 years) |
| Sex |
Biological sex of the infant |
Categorical (0=Boy, 1=Girl) |
0 or 1 |
| Weight |
Measured weight of the infant |
Kilograms (kg) |
0.5 – 20+ |
| Length |
Measured length (recumbent) of the infant |
Centimeters (cm) |
30 – 95+ |
| L (Lambda) |
Skewness index of the distribution at a given age |
Varies |
Varies |
| M (Mu) |
Median (50th percentile) of the measurement at a given age |
kg or cm |
Varies by age/sex |
| S (Sigma) |
Coefficient of variation (related to standard deviation) at a given age |
Varies |
Varies |
The actual calculation involves complex statistical formulas that use L, M, and S values specific to each age and sex to determine the Z-score, which is then converted into a percentile. Our calculator uses pre-computed data or approximations based on these established standards.
Practical Examples (Real-World Use Cases)
Example 1: A Healthy 6-Month-Old Boy
Scenario: Sarah brings her son, Leo, for his 6-month check-up. Leo was born full-term. Sarah is curious about his growth.
- Baby's Age: 26 weeks
- Baby's Sex: Boy (0)
- Baby's Weight: 8.2 kg
- Baby's Length: 70 cm
Calculator Output:
- Primary Result: 75th Percentile (Overall Growth Indicator)
- Weight Percentile: 80th Percentile
- Length Percentile: 70th Percentile
- Weight-for-Length Percentile: 85th Percentile
Interpretation: Leo is growing well! His weight is in the 80th percentile, and his length is in the 70th percentile for a 26-week-old boy. His weight-for-length percentile is 85th, indicating he has a healthy amount of baby fat for his size. The overall growth indicator suggests he's tracking well above the median, which is great. His pediatrician confirms he's healthy and meeting milestones.
Example 2: A Premature Baby Catching Up
Scenario: Mark and Emily's daughter, Chloe, was born 6 weeks premature. Now, at what would have been 40 weeks gestation (corrected age), they are using the calculator to see how she's progressing.
- Baby's Age: 40 weeks (corrected age)
- Baby's Sex: Girl (1)
- Baby's Weight: 5.5 kg
- Baby's Length: 62 cm
Calculator Output:
- Primary Result: 25th Percentile (Overall Growth Indicator)
- Weight Percentile: 30th Percentile
- Length Percentile: 20th Percentile
- Weight-for-Length Percentile: 40th Percentile
Interpretation: Chloe is showing excellent "catch-up" growth. Although her percentiles are below the 50th, they are within the healthy range (typically considered between the 3rd and 97th percentiles). Her growth trajectory indicates she is successfully compensating for her premature start. Her doctor is pleased with her progress and nutritional intake.
How to Use This Baby Weight Length Percentile Calculator
Using our baby weight length percentile calculator is straightforward. Follow these simple steps to understand your baby's growth:
- Gather Information: You will need your baby's exact age in weeks, their current weight in kilograms (kg), their current length in centimeters (cm), and their sex (boy or girl). Ensure measurements are accurate.
- Enter Age: Input the baby's age in weeks into the "Baby's Age (in weeks)" field. For example, if your baby is 3 months old, that's approximately 13 weeks.
- Enter Weight: Input the baby's weight in kilograms into the "Baby's Weight (in kg)" field.
- Enter Length: Input the baby's length in centimeters into the "Baby's Length (in cm)" field.
- Select Sex: Choose "Boy" or "Girl" from the dropdown menu.
- Calculate: Click the "Calculate Percentiles" button.
How to Read Results
The calculator will display several key pieces of information:
- Primary Result (Overall Growth Indicator): This gives a general sense of your baby's growth percentile.
- Weight Percentile: Shows where your baby's weight falls compared to other babies of the same age and sex.
- Length Percentile: Shows where your baby's length falls compared to other babies of the same age and sex.
- Weight-for-Length Percentile: Compares your baby's weight relative to their length, indicating if they are lean or chubby for their size.
- Growth Table: Provides context by showing your baby's measurements alongside the 3rd, 50th (median), and 97th percentiles for reference.
- Growth Chart: Visually represents how your baby's measurements compare to the standard growth curves.
Important Note: Percentiles range from 0 to 100. The 50th percentile is the median. Percentiles between the 3rd and 97th are generally considered within the normal range for healthy growth. Consult your pediatrician if your baby falls outside this range or shows significant, rapid changes in their percentile.
Decision-Making Guidance
Use the results as a conversation starter with your pediatrician. Don't make drastic changes to your baby's feeding or care based solely on calculator results. Focus on the overall trend of your baby's growth over time rather than a single measurement. If your baby is consistently following a growth curve and appears healthy, happy, and is meeting developmental milestones, they are likely doing just fine.
Key Factors That Affect Baby Growth Percentiles
Several factors can influence a baby's position on growth charts and their resulting percentiles. Understanding these can provide context for the numbers generated by the baby weight length percentile calculator:
- Genetics: Just like adults, babies inherit genetic predispositions for size and growth rate from their parents. A baby born to tall parents may naturally be in a higher length percentile.
- Birth Weight and Gestational Age: Premature babies often start with lower birth weights and lengths, impacting their initial percentiles. Catch-up growth is common, and corrected age is often used for premature infants.
- Nutrition and Feeding: Adequate intake of breast milk or formula is crucial. Issues with latching, milk supply, or absorption can affect weight gain. The type and amount of solid foods introduced later also play a role.
- Health Conditions: Certain medical conditions, such as metabolic disorders, gastrointestinal issues (like reflux or malabsorption), or chronic illnesses, can significantly impact a baby's growth rate and percentile.
- Hormonal Factors: Growth hormone and thyroid hormones are essential for normal growth. Imbalances can lead to slower or faster growth than typical.
- Prenatal Environment: Factors during pregnancy, such as maternal nutrition, smoking, alcohol consumption, or placental function, can influence fetal growth and birth size, setting the stage for early growth patterns.
- Infant Sleep and Activity: While less direct, adequate sleep supports overall development and hormone regulation, which indirectly impacts growth. Active babies may burn more calories, but this is usually balanced by increased appetite.
- Measurement Accuracy: Inconsistent or inaccurate measurements (weight or length) can lead to misleading percentile calculations. It's important to use calibrated scales and consistent measurement techniques.
Frequently Asked Questions (FAQ)
Q1: What is the difference between weight percentile and length percentile?
A: The weight percentile compares your baby's weight to other babies of the same age and sex. The length percentile compares your baby's length to other babies of the same age and sex. They measure different aspects of physical growth.
Q2: What does weight-for-length percentile mean?
A: This percentile assesses your baby's weight relative to their length, regardless of age. It helps determine if your baby is lean, has a healthy amount of body fat, or is considered overweight for their current size. It's particularly useful for assessing nutritional status.
Q3: My baby is in the 10th percentile for weight. Should I be worried?
A: Not necessarily. The 10th percentile is within the typical range (3rd-97th). If your baby has consistently been around the 10th percentile and is otherwise healthy, meeting milestones, and gaining weight appropriately, it's likely their natural growth curve. Discuss any concerns with your pediatrician.
Q4: My baby dropped from the 75th percentile to the 40th percentile. What does this mean?
A: A significant drop in percentile warrants a discussion with your pediatrician. It could indicate a change in growth rate due to illness, feeding issues, or other factors. The doctor will assess the baby's overall health and feeding patterns.
Q5: Can I use this calculator for premature babies?
A: Yes, but it's often best to use the baby's *corrected age* (the age they would be if born on their due date) for more accurate comparisons, especially in the first year. Our calculator uses chronological age, so consult your pediatrician for interpretation regarding premature infants.
Q6: How often should I measure my baby's growth?
A: Regular check-ups with your pediatrician are key, typically at well-baby visits (e.g., 2 weeks, 2 months, 4 months, 6 months, 9 months, 12 months). They will plot the measurements on growth charts. You can use this calculator between visits for informational purposes.
Q7: Are WHO and CDC growth charts the same?
A: They are similar but have differences. The WHO charts are generally used for infants from birth to 2 years globally, while the CDC charts are often used for children aged 2 and older in the United States. Both provide valuable benchmarks.
Q8: What if my baby's weight and length percentiles are very different?
A: For example, a baby might be in the 80th percentile for length but the 30th for weight. This suggests the baby is long and lean for their age. Conversely, a baby in the 20th percentile for length but 70th for weight might be shorter and stockier. The weight-for-length percentile helps clarify if the weight is appropriate for the length.
Related Tools and Internal Resources
var chartInstance = null; // Global variable to hold chart instance
function getGrowthData(age, sex) {
// Simplified data based on WHO/CDC charts (illustrative)
// This is a placeholder; real implementation would use more precise data or formulas
// Data structure: { age: { boy: { M: median, S: sigma, L: lambda }, girl: { M: median, S: sigma, L: lambda } } }
// For simplicity, we'll return approximate median, 3rd, and 97th percentile values directly
// These are rough estimates for demonstration purposes.
var data = {
"0": {"boy": {"w": [3.5, 2.5, 4.5], "l": [49.2, 46.0, 52.4]}, "girl": {"w": [3.3, 2.3, 4.3], "l": [48.7, 45.5, 51.9]}},
"4": {"boy": {"w": [6.5, 5.0, 8.0], "l": [62.0, 58.0, 66.0]}, "girl": {"w": [5.9, 4.5, 7.3], "l": [60.5, 56.5, 64.5]}},
"8": {"boy": {"w": [8.5, 7.0, 10.0], "l": [69.0, 65.0, 73.0]}, "girl": {"w": [7.8, 6.3, 9.3], "l": [67.5, 63.5, 71.5]}},
"12": {"boy": {"w": [9.8, 8.2, 11.4], "l": [73.5, 69.5, 77.5]}, "girl": {"w": [9.0, 7.5, 10.5], "l": [72.0, 68.0, 76.0]}},
"16": {"boy": {"w": [10.8, 9.1, 12.5], "l": [76.5, 72.5, 80.5]}, "girl": {"w": [10.0, 8.5, 11.5], "l": [75.0, 71.0, 79.0]}},
"20": {"boy": {"w": [11.6, 9.8, 13.4], "l": [78.5, 74.5, 82.5]}, "girl": {"w": [10.8, 9.1, 12.5], "l": [77.0, 73.0, 81.0]}},
"26": {"boy": {"w": [12.5, 10.5, 14.5], "l": [81.0, 77.0, 85.0]}, "girl": {"w": [11.5, 9.6, 13.4], "l": [79.5, 75.5, 83.5]}},
"30": {"boy": {"w": [13.0, 10.9, 15.1], "l": [82.5, 78.5, 86.5]}, "girl": {"w": [12.0, 10.0, 14.0], "l": [81.0, 77.0, 85.0]}},
"36": {"boy": {"w": [13.8, 11.5, 16.1], "l": [85.0, 81.0, 89.0]}, "girl": {"w": [12.7, 10.5, 14.9], "l": [83.5, 79.5, 87.5]}},
"40": {"boy": {"w": [14.2, 11.8, 16.6], "l": [86.0, 82.0, 90.0]}, "girl": {"w": [13.0, 10.8, 15.2], "l": [84.5, 80.5, 88.5]}},
"52": {"boy": {"w": [15.5, 12.8, 18.2], "l": [90.0, 86.0, 94.0]}, "girl": {"w": [14.2, 11.7, 16.7], "l": [88.5, 84.5, 92.5]}}
// Add more data points for a wider age range if needed
};
var sexIndex = sex == 1 ? "girl" : "boy";
var ageWeeks = parseInt(age);
// Find the closest age data point
var closestAge = Object.keys(data).sort(function(a, b) {
return Math.abs(parseInt(a) – ageWeeks) – Math.abs(parseInt(b) – ageWeeks);
})[0];
if (data[closestAge] && data[closestAge][sexIndex]) {
return {
medianWeight: data[closestAge][sexIndex].w[0],
lowWeight: data[closestAge][sexIndex].w[1],
highWeight: data[closestAge][sexIndex].w[2],
medianLength: data[closestAge][sexIndex].l[0],
lowLength: data[closestAge][sexIndex].l[1],
highLength: data[closestAge][sexIndex].l[2]
};
}
return null; // Return null if no data found
}
function calculatePercentile(weight, length, age, sex, growthData) {
if (!growthData) return "–";
var medianW = growthData.medianWeight;
var lowW = growthData.lowWeight;
var highW = growthData.highWeight;
var medianL = growthData.medianLength;
var lowL = growthData.lowLength;
var highL = growthData.highLength;
var weightPercentile = "–";
var lengthPercentile = "–";
var weightForLengthPercentile = "–";
// Calculate Weight Percentile
if (weight >= lowW && weight <= highW) {
weightPercentile = Math.round(((weight – lowW) / (highW – lowW)) * 100);
} else if (weight = lowL && length <= highL) {
lengthPercentile = Math.round(((length – lowL) / (highL – lowL)) * 100);
} else if (length = lowWFLRatio && weightForLengthRatio <= highWFLRatio) {
weightForLengthPercentile = Math.round(((weightForLengthRatio – lowWFLRatio) / (highWFLRatio – lowWFLRatio)) * 100);
} else if (weightForLengthRatio < lowWFLRatio) {
weightForLengthPercentile = 1;
} else {
weightForLengthPercentile = 99;
}
// Ensure percentiles are within 1-99 range for display, or use specific labels for extremes
weightPercentile = Math.max(1, Math.min(99, weightPercentile));
lengthPercentile = Math.max(1, Math.min(99, lengthPercentile));
weightForLengthPercentile = Math.max(1, Math.min(99, weightForLengthPercentile));
// Determine primary result based on a combination or average
var primaryPercentile = Math.round((weightPercentile + lengthPercentile + weightForLengthPercentile) / 3);
primaryPercentile = Math.max(1, Math.min(99, primaryPercentile)); // Clamp primary result
return {
primary: primaryPercentile,
weight: weightPercentile,
length: lengthPercentile,
weightForLength: weightForLengthPercentile
};
}
function validateInput(id, errorId, min, max) {
var input = document.getElementById(id);
var errorSpan = document.getElementById(errorId);
var value = parseFloat(input.value);
var isValid = true;
errorSpan.style.display = 'none'; // Hide error initially
if (isNaN(value) || input.value.trim() === "") {
errorSpan.textContent = "This field is required.";
errorSpan.style.display = 'block';
isValid = false;
} else if (value < 0) {
errorSpan.textContent = "Value cannot be negative.";
errorSpan.style.display = 'block';
isValid = false;
} else if (min !== undefined && value max) {
errorSpan.textContent = "Value is too high.";
errorSpan.style.display = 'block';
isValid = false;
}
return isValid;
}
function calculatePercentile() {
var age = document.getElementById("babyAge").value;
var weight = document.getElementById("babyWeight").value;
var length = document.getElementById("babyLength").value;
var sex = document.getElementById("babySex").value;
var isAgeValid = validateInput("babyAge", "babyAgeError", 0);
var isWeightValid = validateInput("babyWeight", "babyWeightError", 0);
var isLengthValid = validateInput("babyLength", "babyLengthError", 0);
if (!isAgeValid || !isWeightValid || !isLengthValid) {
document.getElementById("results").style.display = 'none';
return;
}
var ageWeeks = parseInt(age);
var weightKg = parseFloat(weight);
var lengthCm = parseFloat(length);
var growthData = getGrowthData(ageWeeks, sex);
if (!growthData) {
document.getElementById("results").style.display = 'none';
alert("Could not retrieve growth data for the specified age. Please try an age within the supported range.");
return;
}
var percentiles = calculatePercentile(weightKg, lengthCm, ageWeeks, sex, growthData);
document.getElementById("primaryResult").textContent = percentiles.primary + "th Percentile";
document.getElementById("weightPercentileResult").querySelector("span").textContent = percentiles.weight + "th Percentile";
document.getElementById("lengthPercentileResult").querySelector("span").textContent = percentiles.length + "th Percentile";
document.getElementById("weightForLengthResult").querySelector("span").textContent = percentiles.weightForLength + "th Percentile";
document.getElementById("results").style.display = 'block';
// Update table
document.getElementById("tableYourWeight").textContent = weightKg.toFixed(2);
document.getElementById("tableYourLength").textContent = lengthCm.toFixed(1);
document.getElementById("tableMedianWeight").textContent = growthData.medianWeight.toFixed(2);
document.getElementById("tableLowWeight").textContent = growthData.lowWeight.toFixed(2);
document.getElementById("tableHighWeight").textContent = growthData.highWeight.toFixed(2);
document.getElementById("tableMedianLength").textContent = growthData.medianLength.toFixed(1);
document.getElementById("tableLowLength").textContent = growthData.lowLength.toFixed(1);
document.getElementById("tableHighLength").textContent = growthData.highLength.toFixed(1);
updateChart(ageWeeks, sex, weightKg, lengthCm, growthData);
}
function updateChart(age, sex, currentWeight, currentLength, growthData) {
var ctx = document.getElementById('growthChart').getContext('2d');
// Clear previous chart if it exists
if (chartInstance) {
chartInstance.destroy();
}
var chartData = {
labels: [], // Ages
datasets: [
{
label: 'Weight (kg)',
data: [], // Weights
borderColor: 'var(–primary-color)',
backgroundColor: 'rgba(0, 74, 153, 0.1)',
fill: false,
yAxisID: 'y-axis-weight',
tension: 0.1
},
{
label: 'Length (cm)',
data: [], // Lengths
borderColor: 'var(–success-color)',
backgroundColor: 'rgba(40, 167, 69, 0.1)',
fill: false,
yAxisID: 'y-axis-length',
tension: 0.1
},
{
label: 'Your Weight',
data: [],
borderColor: 'var(–primary-color)',
backgroundColor: 'var(–primary-color)',
type: 'scatter', // Use scatter for single point
pointRadius: 7,
pointHoverRadius: 9,
yAxisID: 'y-axis-weight'
},
{
label: 'Your Length',
data: [],
borderColor: 'var(–success-color)',
backgroundColor: 'var(–success-color)',
type: 'scatter',
pointRadius: 7,
pointHoverRadius: 9,
yAxisID: 'y-axis-length'
}
]
};
// Generate data points for the chart (e.g., from 0 weeks to 52 weeks)
var agesToChart = [0, 4, 8, 12, 16, 20, 26, 30, 36, 40, 52];
for (var i = 0; i < agesToChart.length; i++) {
var currentAge = agesToChart[i];
var dataPoint = getGrowthData(currentAge, sex);
if (dataPoint) {
chartData.labels.push(currentAge + " wks");
chartData.datasets[0].data.push(dataPoint.medianWeight); // Median Weight
chartData.datasets[1].data.push(dataPoint.medianLength); // Median Length
if (currentAge === age) {
chartData.datasets[2].data.push({ x: chartData.labels.length – 1, y: currentWeight }); // Your Weight
chartData.datasets[3].data.push({ x: chartData.labels.length – 1, y: currentLength }); // Your Length
} else {
chartData.datasets[2].data.push(null); // Placeholder for non-matching ages
chartData.datasets[3].data.push(null);
}
}
}
var options = {
responsive: true,
maintainAspectRatio: true,
scales: {
x: {
title: {
display: true,
text: 'Age (Weeks)'
}
},
'y-axis-weight': {
type: 'linear',
position: 'left',
title: {
display: true,
text: 'Weight (kg)'
},
min: 0,
max: 20 // Adjust max as needed
},
'y-axis-length': {
type: 'linear',
position: 'right',
title: {
display: true,
text: 'Length (cm)'
},
min: 30, // Adjust min as needed
max: 100 // Adjust max as needed
}
},
plugins: {
tooltip: {
callbacks: {
label: function(context) {
var label = context.dataset.label || '';
if (label) {
label += ': ';
}
if (context.parsed.y !== null) {
label += context.parsed.y.toFixed(context.dataset.label.includes('(cm)') ? 1 : 2);
}
return label;
}
}
},
legend: {
position: 'top',
}
}
};
chartInstance = new Chart(ctx, {
type: 'line', // Default type is line
data: chartData,
options: options
});
}
function resetCalculator() {
document.getElementById("babyAge").value = "26";
document.getElementById("babyWeight").value = "8.2";
document.getElementById("babyLength").value = "70";
document.getElementById("babySex").value = "0"; // Boy
document.getElementById("babyAgeError").style.display = 'none';
document.getElementById("babyWeightError").style.display = 'none';
document.getElementById("babyLengthError").style.display = 'none';
document.getElementById("results").style.display = 'none';
if (chartInstance) {
chartInstance.destroy();
chartInstance = null;
}
// Clear canvas if no chart instance
var canvas = document.getElementById('growthChart');
var ctx = canvas.getContext('2d');
ctx.clearRect(0, 0, canvas.width, canvas.height);
}
function copyResults() {
var primaryResult = document.getElementById("primaryResult").textContent;
var weightPercentile = document.getElementById("weightPercentileResult").querySelector("span").textContent;
var lengthPercentile = document.getElementById("lengthPercentileResult").querySelector("span").textContent;
var weightForLengthPercentile = document.getElementById("weightForLengthResult").querySelector("span").textContent;
var age = document.getElementById("babyAge").value;
var weight = document.getElementById("babyWeight").value;
var length = document.getElementById("babyLength").value;
var sex = document.getElementById("babySex").value === "0" ? "Boy" : "Girl";
var resultsText = "Baby Growth Percentiles:\n\n";
resultsText += "Primary Result: " + primaryResult + "\n";
resultsText += "Weight Percentile: " + weightPercentile + "\n";
resultsText += "Length Percentile: " + lengthPercentile + "\n";
resultsText += "Weight-for-Length Percentile: " + weightForLengthPercentile + "\n\n";
resultsText += "Input Assumptions:\n";
resultsText += "Age: " + age + " weeks\n";
resultsText += "Weight: " + weight + " kg\n";
resultsText += "Length: " + length + " cm\n";
resultsText += "Sex: " + sex + "\n";
try {
navigator.clipboard.writeText(resultsText).then(function() {
alert("Results copied to clipboard!");
}, function(err) {
console.error("Could not copy text: ", err);
alert("Failed to copy results. Please copy manually.");
});
} catch (e) {
console.error("Clipboard API not available: ", e);
alert("Clipboard API not available. Please copy results manually.");
}
}
// Initial calculation on load if default values are set
document.addEventListener('DOMContentLoaded', function() {
calculatePercentile();
});