.gfr-calculator-wrapper {
max-width: 800px;
margin: 0 auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
}
.gfr-box {
background-color: #f9fbfd;
border: 1px solid #e1e4e8;
border-radius: 8px;
padding: 30px;
margin-bottom: 40px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.gfr-title {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
font-size: 24px;
font-weight: 600;
}
.input-group {
margin-bottom: 20px;
}
.input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #4a5568;
}
.input-group input {
width: 100%;
padding: 12px;
border: 1px solid #cbd5e0;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
transition: border-color 0.2s;
}
.input-group input:focus {
border-color: #3182ce;
outline: none;
box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.1);
}
.help-text {
font-size: 12px;
color: #718096;
margin-top: 5px;
}
.calc-btn {
display: block;
width: 100%;
background-color: #3182ce;
color: white;
border: none;
padding: 14px;
font-size: 18px;
font-weight: 600;
border-radius: 6px;
cursor: pointer;
transition: background-color 0.2s;
margin-top: 10px;
}
.calc-btn:hover {
background-color: #2c5282;
}
.result-box {
margin-top: 25px;
padding: 20px;
background-color: #fff;
border: 1px solid #e2e8f0;
border-radius: 6px;
text-align: center;
display: none;
}
.result-value {
font-size: 36px;
font-weight: 700;
color: #2b6cb0;
margin-bottom: 10px;
}
.result-label {
font-size: 16px;
color: #4a5568;
font-weight: 500;
}
.article-content h2 {
color: #2d3748;
border-bottom: 2px solid #edf2f7;
padding-bottom: 10px;
margin-top: 40px;
}
.article-content h3 {
color: #4a5568;
margin-top: 25px;
}
.article-content p {
margin-bottom: 15px;
}
.example-box {
background-color: #f0fff4;
border-left: 4px solid #48bb78;
padding: 15px;
margin: 20px 0;
}
.formula-box {
background-color: #edf2f7;
padding: 15px;
border-radius: 6px;
font-family: monospace;
text-align: center;
font-size: 18px;
margin: 20px 0;
}
function calculateGFR() {
var birthsInput = document.getElementById('totalBirths');
var popInput = document.getElementById('femalePopulation');
var resultContainer = document.getElementById('resultContainer');
var gfrValueDisplay = document.getElementById('gfrValue');
var births = parseFloat(birthsInput.value);
var population = parseFloat(popInput.value);
if (isNaN(births) || isNaN(population)) {
alert("Please enter valid numbers for both fields.");
resultContainer.style.display = "none";
return;
}
if (population <= 0) {
alert("Female population must be greater than zero.");
resultContainer.style.display = "none";
return;
}
if (births < 0) {
alert("Number of births cannot be negative.");
resultContainer.style.display = "none";
return;
}
// GFR Formula: (Live Births / Female Population 15-44) * 1000
var gfr = (births / population) * 1000;
// Round to 1 decimal place for standard reporting
gfr = Math.round(gfr * 10) / 10;
gfrValueDisplay.innerHTML = gfr;
resultContainer.style.display = "block";
}
Understanding the General Fertility Rate (GFR)
The General Fertility Rate (GFR) is a critical demographic indicator used to measure the frequency of childbearing within a population. Unlike the Crude Birth Rate (which compares births to the total population regardless of age or sex), the GFR is more refined because it relates the number of births specifically to the population of women who are of reproductive age.
Demographers typically define "reproductive age" as women between the ages of 15 and 44 (or sometimes 15 and 49). By focusing on this specific demographic, the GFR provides a more accurate picture of fertility trends than broader metrics.
The Formula
To calculate the General Fertility Rate, you need two specific data points for a given year and geographic area:
GFR = ( B / P ) × 1,000
Where:
- B = Total number of live births in the year.
- P = Mid-year population of women of reproductive age (15-44 or 15-49).
- 1,000 = The multiplier used to express the rate "per 1,000 women."
General Fertility Rate Calculation Example
Let's look at a realistic scenario to understand how the math works in practice. Suppose you are analyzing the fertility data for a mid-sized city named "Demographica."
Scenario: City of Demographica
- Total Live Births (B): 2,450
- Female Population aged 15-44 (P): 38,000
Step 1: Divide Births by Population
2,450 ÷ 38,000 = 0.06447
Step 2: Multiply by 1,000
0.06447 × 1,000 = 64.5
Result: The General Fertility Rate is 64.5 births per 1,000 women of reproductive age.
Interpreting the Results
The result tells us how many babies are born for every 1,000 women capable of giving birth. A higher GFR indicates a population that is reproducing at a faster rate relative to the number of potential mothers.
- Trend Analysis: If the GFR drops from 65.0 to 60.0 over five years, it indicates a decline in fertility, which could be due to economic factors, delayed family planning, or social changes.
- Comparison: GFR allows for better comparison between different regions or countries with different population structures than the Crude Birth Rate does.
Difference Between GFR and Total Fertility Rate (TFR)
While GFR is a great snapshot, it is different from the Total Fertility Rate (TFR). The GFR tells you the rate of births per 1,000 women right now. The TFR estimates the average number of children one woman would have over her lifetime if current age-specific birth rates remained constant. Both are essential for understanding population dynamics.