What Is a Percentage Calculator?
A percentage calculator turns a ratio between two numbers into a percentage, or applies a percentage to a number, so you don't have to do the arithmetic by hand. This page is a full percentage calculators hub: it covers finding a percentage, calculating percentage increase or decrease, percentage difference, converting a fraction to a percentage, CGPA to percentage, and even body fat percentage — all using the calculation type selector above.
How to Calculate Percentage (Formula & Steps)
To find what percentage one number is of another, the formula is:
For example, to find what percentage 25 is of 200: divide 25 by 200 to get 0.125, then multiply by 100 to get 12.5%. To go the other way — finding X% of a number — multiply the number by X and divide by 100. For example, 20% of 80 is (80 × 20) ÷ 100 = 16.
How to Calculate Percentage Increase (and Decrease)
Percentage increase or decrease measures how much a value has changed relative to its original value:
If the result is positive, it's a percentage increase; if it's negative, it's a percentage decrease. For example, going from 50 to 75 is ((75−50)÷50)×100 = 50% increase. Going from 80 to 60 is ((60−80)÷80)×100 = −25%, meaning a 25% decrease. The "Percentage Increase / Decrease" mode above calculates this automatically and tells you which direction it went.
Percentage Change vs Percentage Difference
These two terms are often confused, but they answer different questions:
Percentage change assumes one value is the "original" and the other is the "new" value, so it has a direction (increase or decrease) and always divides by the original value. Percentage difference treats both values equally — neither is the "original" — and divides the absolute difference by the average of the two values instead:
Because of this, comparing 40 and 60 gives a 50% difference (using their average of 50 as the base) but a 50% increase if you treat 40 as the original value going up to 60 — two different, both-correct answers to two different questions. Use "Percentage Difference" above when neither number is clearly the starting point, and "Percentage Increase / Decrease" when one clearly is.
Converting a Fraction to a Percentage
To convert any fraction to a percentage, divide the numerator by the denominator and multiply by 100. A few common examples:
| Fraction | As a Percentage |
|---|---|
| 16 out of 20 | 80% |
| 6/7 | ≈ 85.71% |
| 3/4 | 75% |
| 7/8 | 87.5% |
| 9/10 | 90% |
| 5/6 | ≈ 83.33% |
| 18 out of 25 | 72% |
Need a fraction that isn't listed here? Select "Fraction to Percentage" in the calculator above and enter any two numbers for an instant, exact result.
Body Fat Percentage Calculator (US Navy Method)
The U.S. Navy method estimates body fat percentage from simple tape-measure circumference measurements — neck and waist for men, plus hip for women — combined with height, using a logarithmic formula developed for military fitness assessments. It's less precise than lab methods like DEXA scans or skinfold calipers, but it needs nothing more than a tape measure.
Select "Body Fat Percentage (US Navy Method)" in the calculator above, choose your gender and units, and enter your measurements for an instant estimate plus your category based on the American Council on Exercise (ACE) classification below.
Body Fat Percentage Chart (ACE Categories)
| Category | Men | Women |
|---|---|---|
| Essential Fat | 2–5% | 10–13% |
| Athletes | 6–13% | 14–20% |
| Fitness | 14–17% | 21–24% |
| Average | 18–24% | 25–31% |
| Obese | 25%+ | 32%+ |
Source: American Council on Exercise (ACE) body-fat classification. These are general population reference ranges, not medical diagnoses — consult a doctor or registered dietitian for personal health guidance.
CGPA to Percentage
If your university grades on a CGPA scale, select "CGPA ↔ Percentage" in the calculator above to convert in either direction. The formulas used, based on your selected scale, are:
Not every university uses the exact same multiplier — some use (CGPA − 0.75) × 10 instead. This calculator uses the most widely accepted approximation for each scale; for anything official (transcripts, visa applications, job forms), always check your institution's stated formula. For a more detailed university-by-university breakdown, see our CGPA calculator.
Frequently Asked Questions
To find what percentage one number is of another, divide the part by the whole and multiply by 100: Percentage = (Part ÷ Whole) × 100. To find X% of a number, multiply the number by X and divide by 100.
16 out of 20 is 80%. This comes from (16 ÷ 20) × 100 = 80.
6/7 as a percentage is approximately 85.71%. This comes from (6 ÷ 7) × 100 = 85.71.
Subtract the original value from the new value, divide that difference by the original value, then multiply by 100: Percentage Increase = ((New − Original) ÷ Original) × 100. If the result is negative, it's a percentage decrease instead.
Percentage change compares a new value to an original value, so it has a direction (increase or decrease) and uses the original value as the base. Percentage difference compares two values with neither treated as the "original", using their average as the base, so it's always positive and symmetric between the two numbers.
Divide the smaller or "part" number by the larger or "whole" number, then multiply by 100. For example, to find what percentage 25 is of 200, calculate (25 ÷ 200) × 100 = 12.5%.
According to the American Council on Exercise (ACE) classification, a healthy (non-athlete) range is about 18-24% for men and 25-31% for women. Athletes typically measure lower, around 6-13% for men and 14-20% for women, while below 2-5% (men) or 10-13% (women) is considered essential fat, the minimum needed for basic body function.
This calculator uses the U.S. Navy circumference method, which estimates body fat from neck, waist, height, and (for women) hip measurements using a logarithmic formula developed by the Navy. It's an estimate based on circumference, not a direct measurement like a DEXA scan or skinfold calipers.
Yes. Select "CGPA to Percentage" from the calculation type dropdown above to convert between CGPA and percentage on the 4.0, 5.0, or 10.0 scale, in either direction.
Yes. Every calculation type on this page can be used online without creating an account.