Percentage Calculator

Calculate percentages three ways: find X% of a number, find what percent X is of Y, or find the percent change between two values. Free, instant, no signup.

How to use the Percentage Calculator

  1. Enter your values. Fill in the fields with your numbers.
  2. Calculate. Press Calculate to run the percentage calculator.
  3. Use the result. Copy the result or try a related tool next.

Why use our Percentage Calculator

Instant results. Enter your figures and the percentage calculator returns an answer in seconds.
Free & private. Runs in your browser — no signup, and nothing is sent to a server.
Accurate. Uses standard formulas so you can rely on the numbers.

Free to use — premium coming soon

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  • Instant results
  • No signup
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About the Percentage Calculator

The Percentage Calculator handles the three percentage questions that come up most often in everyday life and work. The first is finding a percentage of a number: what is 15% of 80? The second is working out what percent one number is of another: 25 out of 200 is what percentage? The third is percentage change: if a price moved from 40 to 50, by how much did it rise? Each calculation lives behind the percent sign, which literally means "per hundred", so every answer is just a value expressed against a base of 100.

Reach for this tool whenever a raw number alone does not tell the whole story. Shoppers use it to check that an advertised 30% discount really knocks the price down to what the till shows. Students convert a score of 47 out of 60 into an exam percentage. Sales staff measure how far they are through a quota, and managers compare this quarter's revenue against last quarter's. Because it covers all three percentage operations in one place, you do not have to remember which formula matches which question, only which number is the part and which is the whole.

Under the hood the math is deliberately simple and transparent. A percentage of a number is (percent divided by 100) times the number, so 15% of 80 becomes 0.15 times 80, or 12. To find what percent one value is of another, divide the part by the whole and multiply by 100: 25 divided by 200, times 100, is 12.5%. Percentage change divides the gain or loss by the original value, so a move from 40 to 50 is (50 minus 40) divided by 40, times 100, which equals a 25% increase. The calculator simply applies these steps and shows the result.

Every calculation runs entirely in your browser, so the numbers you type are never uploaded to a server or stored anywhere. That keeps salaries, invoice totals, grades, or any other figures completely private. Results are computed with standard floating-point arithmetic and are accurate to far more decimal places than most everyday tasks require; we round the displayed answer for readability. If you need a particular number of decimals for accounting or coursework, check the rounding on the figures you enter, since small rounding differences in the inputs are the most common reason two calculators disagree.

Frequently asked questions

How do I calculate a percentage of a number?

Convert the percentage to a decimal by dividing it by 100, then multiply by the number. For example, 20% of 150 is 0.20 times 150, which equals 30.

How do I find what percent one number is of another?

Divide the part by the whole and multiply by 100. So 30 out of 120 is (30 divided by 120) times 100, which equals 25%.

What is the difference between percentage change and percentage points?

Percentage points are the plain arithmetic gap between two percentages, while percentage change measures that gap relative to the starting value. A rate moving from 5% to 7% is a rise of 2 percentage points, but a 40% increase.

How is percentage increase or decrease calculated?

Subtract the old value from the new value, divide by the old value, and multiply by 100. A change from 80 to 100 is (100 minus 80) divided by 80, times 100, or a 25% increase; a negative result means a decrease.

Are my numbers sent anywhere when I use this calculator?

No. Every calculation runs locally in your browser, so the values you enter are never transmitted to a server or saved, keeping financial figures and grades private.

From our blog

How the Army One-Site Tape Test Works and How to Estimate Your Score

By the Super Simple Digital Tools Team · Updated June 2026

The Army Body Composition Program exists to keep soldiers within a healthy body composition range, and in 2024 it moved to a simpler way of measuring it. Where the old method required taping multiple sites and applying log-based equations, the current one-site test asks for just your body weight and the circumference of your abdomen. That change makes the assessment faster, more consistent between graders, and easy to replicate at home, which is exactly what this calculator does.

The process starts with a screening, not a tape. Each soldier is first checked against a height and weight table for their age and sex. If you fall at or under the maximum screening weight for your height, you meet the standard and no tape test is needed. Only when you exceed that weight does the abdominal measurement come into play to determine your body fat percentage, so knowing your number in advance tells you whether the tape will ever come out.

Taking the measurement correctly matters more than people expect. Use a flexible tape that does not stretch, remove belts and bulky clothing, and stand tall with feet about hip-width apart. Place the tape at the level of your navel, keep it horizontal all the way around, and snug it against the skin without compressing the tissue. Read it at the end of a relaxed breath out. Because a single reading can be off, the Army takes three and averages them to the nearest half inch.

Once you have weight and abdomen in hand, the formula does the rest. Men and women use different equations because body fat distributes differently, but both depend only on those two inputs. Plug your averaged abdomen measurement and current weight into the calculator and it returns an estimated percentage. The tool then compares that figure to the maximum allowed for your age group, giving you a clear pass or work-needed signal rather than just a raw number.

Treat the output as a planning tool. Trends matter more than any one reading: track your estimate every couple of weeks as you train, and you will see how abdominal measurement responds to changes in diet and conditioning. When an official assessment is on the calendar, measure under the same conditions each time so your home estimates stay comparable, and remember that your unit's graded result is the one that counts on the record.

  • Average three abdomen readings to the nearest half inch, just as a grader would, instead of trusting a single measurement.
  • Measure at the navel at the end of a relaxed exhale, and never suck in or push your stomach out.
  • Compare your weight to the height and weight screening table first; if you are under it, the tape test may not apply at all.
  • Re-check your estimate at the same time of day and in similar conditions so progress between sessions is genuinely comparable.

Read the full guide →

Tool by the Super Simple Digital Tools Team. Reviewed by our editorial team. Free to use, no signup required.

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