Calculate any missing variable in the percentage formula instantly.
1. Find the Part (Percentage)
Formula: Part = Base × Rate
2. Find the Base (Whole Value)
Formula: Base = Part / Rate
3. Find the Rate (Percentage)
Formula: Rate = (Part / Base) × 100
Understanding Base, Rate, and Percentage
In mathematics, the relationship between three fundamental values—Base, Rate, and Percentage—forms the foundation of most commercial and statistical calculations. This calculator helps you solve for any one of these three variables when the other two are known.
1. The Base (B)
The Base is the whole amount or the total value. It represents 100%. For example, if you have a collection of 200 stamps, 200 is your Base.
2. The Rate (R)
The Rate is the ratio or the percent. It is usually expressed with a percent sign (%) or as a decimal. If we say "15% of the stamps are rare," the 15% is the Rate.
3. The Percentage or Part (P)
The Percentage (often confusingly named, as it refers to the result, not the rate) is the part or portion of the base. Using the stamp example, if 15% of 200 stamps are rare, then 30 stamps are rare. Here, 30 is the Part (Percentage).
How to Calculate Manually
Goal
Formula
Example
Find Part
P = B × R
500 × 0.10 = 50
Find Base
B = P / R
50 / 0.10 = 500
Find Rate
R = (P / B) × 100
(50 / 500) × 100 = 10%
Practical Examples
Sales Tax: If a laptop costs 1,200 (Base) and the tax is 8% (Rate), the tax amount (Part) is 96.
Test Scores: If you got 45 questions correct (Part) out of 60 (Base), your score (Rate) is 75%.
Discounts: If you saved 40 (Part) using a 20% off coupon (Rate), the original price (Base) was 200.
function calculatePart() {
var base = parseFloat(document.getElementById('base1').value);
var rate = parseFloat(document.getElementById('rate1').value);
var display = document.getElementById('resultPart');
if (isNaN(base) || isNaN(rate)) {
display.innerHTML = "Please enter valid numbers for Base and Rate.";
display.style.color = "#dc3545";
return;
}
var result = base * (rate / 100);
display.innerHTML = "The Part (Percentage Value) is: " + result.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 4});
display.style.color = "#0056b3";
}
function calculateBase() {
var part = parseFloat(document.getElementById('part2').value);
var rate = parseFloat(document.getElementById('rate2').value);
var display = document.getElementById('resultBase');
if (isNaN(part) || isNaN(rate) || rate === 0) {
display.innerHTML = "Please enter valid numbers (Rate cannot be zero).";
display.style.color = "#dc3545";
return;
}
var result = part / (rate / 100);
display.innerHTML = "The Base (Whole Value) is: " + result.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 4});
display.style.color = "#28a745";
}
function calculateRate() {
var part = parseFloat(document.getElementById('part3').value);
var base = parseFloat(document.getElementById('base3').value);
var display = document.getElementById('resultRate');
if (isNaN(part) || isNaN(base) || base === 0) {
display.innerHTML = "Please enter valid numbers (Base cannot be zero).";
display.style.color = "#dc3545";
return;
}
var result = (part / base) * 100;
display.innerHTML = "The Rate is: " + result.toLocaleString(undefined, {minimumFractionDigits: 0, maximumFractionDigits: 4}) + "%";
display.style.color = "#dc3545";
}