.calc-container {
max-width: 800px;
margin: 20px auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
background: #fff;
padding: 30px;
border-radius: 12px;
box-shadow: 0 4px 20px rgba(0,0,0,0.1);
}
.calc-header {
text-align: center;
margin-bottom: 30px;
color: #2c3e50;
}
.calc-row {
display: flex;
flex-wrap: wrap;
gap: 20px;
margin-bottom: 20px;
}
.calc-col {
flex: 1;
min-width: 250px;
}
.calc-label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #34495e;
}
.calc-input {
width: 100%;
padding: 12px;
border: 2px solid #e0e0e0;
border-radius: 8px;
font-size: 16px;
transition: border-color 0.3s;
box-sizing: border-box;
}
.calc-input:focus {
border-color: #3498db;
outline: none;
}
.calc-btn {
width: 100%;
padding: 15px;
background: #3498db;
color: white;
border: none;
border-radius: 8px;
font-size: 18px;
font-weight: bold;
cursor: pointer;
transition: background 0.3s;
margin-top: 10px;
}
.calc-btn:hover {
background: #2980b9;
}
.result-box {
margin-top: 30px;
background: #f8f9fa;
padding: 25px;
border-radius: 8px;
border-left: 5px solid #3498db;
display: none;
}
.result-row {
display: flex;
justify-content: space-between;
margin-bottom: 15px;
padding-bottom: 15px;
border-bottom: 1px solid #e9ecef;
}
.result-row:last-child {
border-bottom: none;
margin-bottom: 0;
padding-bottom: 0;
}
.result-label {
color: #7f8c8d;
font-size: 16px;
}
.result-value {
font-weight: bold;
color: #2c3e50;
font-size: 18px;
}
.article-section {
max-width: 800px;
margin: 40px auto;
padding: 20px;
line-height: 1.6;
color: #333;
}
.article-section h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #3498db;
padding-bottom: 10px;
}
.article-section p {
margin-bottom: 15px;
}
.article-section ul {
margin-bottom: 20px;
padding-left: 20px;
}
.article-section li {
margin-bottom: 8px;
}
.info-box {
background: #e8f6f3;
padding: 15px;
border-radius: 6px;
margin: 20px 0;
border: 1px solid #d4efdf;
}
function calculatePersonTime() {
// Get input values
var basePeople = parseFloat(document.getElementById('basePeople').value);
var baseTime = parseFloat(document.getElementById('baseTime').value);
var newPeople = parseFloat(document.getElementById('newPeople').value);
var hourlyRate = parseFloat(document.getElementById('hourlyRate').value);
// Validation
if (isNaN(basePeople) || basePeople <= 0) {
alert("Please enter a valid baseline number of people.");
return;
}
if (isNaN(baseTime) || baseTime < 0) {
alert("Please enter a valid baseline time.");
return;
}
if (isNaN(newPeople) || newPeople 0) {
totalCost = totalEffort * hourlyRate;
}
// Time Difference
var timeDiff = baseTime – newTime;
var diffText = "";
if (timeDiff > 0) {
diffText = timeDiff.toFixed(2) + " Hours Saved";
} else if (timeDiff 0 ? currencyFormatter.format(totalCost) : "N/A";
// Show results
document.getElementById('result').style.display = 'block';
}
Understanding Person Time Rate Calculations
The Person Time Rate Calculator is an essential tool for project managers, contractors, and team leads. It helps determine the relationship between the workforce size (number of people) and the time required to complete a specific task. This concept is often referred to as "Man-Hours" or "Person-Hours."
Key Formula:
Total Effort = Number of People × Time
New Time = Total Effort ÷ New Team Size
What are Person-Hours?
A person-hour is a unit of work measuring the effort required for one person to complete a task in one hour. It is the fundamental metric for estimation in various industries, including construction, software development, and consulting.
For example, if a task takes 1 person 100 hours to complete, the total effort is 100 person-hours. Theoretically, if you assign 2 people to the same task, it should take 50 hours (100 ÷ 2).
How to Use This Calculator
- Baseline Number of People: Enter the number of people currently assigned or used in your initial estimate (often 1).
- Baseline Time Duration: Enter how long the task takes for the baseline number of people to complete.
- Proposed Team Size: Enter the number of people you plan to assign to the job.
- Hourly Labor Cost: (Optional) Enter the average hourly wage to estimate the total labor cost for the project.
The Law of Diminishing Returns
While this calculator uses a linear mathematical model (inverse proportion), real-world scenarios often face "The Mythical Man-Month" effect. Adding more people to a late project may make it later due to communication overhead, onboarding time, and resource contention.
When using these calculations, consider:
- Communication Overhead: More people means more meetings and coordination.
- Task Divisibility: Not all tasks can be split perfectly. 9 women cannot make a baby in 1 month.
- Skill Levels: A senior expert works faster than a junior novice, affecting the "rate" variable.
Applications of Person Time Rate
Construction: Estimating how many days a crew needs to paint a building based on square footage rates.
Software Engineering: Sizing development sprints based on developer capacity.
Manufacturing: Calculating throughput and assembly line staffing requirements.