Percentage calculator

The four most common percentage calculations, pick one and enter your numbers.

About the percentage calculator

The BapTools percentage calculator brings the four most common percentage problems into one place so you do not have to work them out in your head. Results appear instantly.

The four percentage problems people need

  • Find a percentage of a number: 15% of 250 is 37.5.
  • Find what percent a number is: 40 is what percent of 250? 16%.
  • Increase by a percentage: 800 increased by 20% is 960.
  • Decrease by a percentage: 800 decreased by 20% is 640.

Percent change versus percentage points

Going from 200 to 250 is a 25% increase. But moving from a score of 4 to 5 is a gain of 1 point, which also equals 25% - two ways of describing the same change.

Real-world examples

Example 1 — 8% tax on an invoice

Invoice total 2,500,000. Pick "Increase by X%", enter 8 and 2,500,000, and you get 2,700,000. The actual tax is the 200,000 difference.

Example 2 — turning a sale price into a discount

Original 800,000, now 640,000. Pick "X is what percent of Y", enter 640,000 and 800,000, and you get 80%, meaning a 20% discount.

Example 3 — quarter-on-quarter growth

Last quarter 450 million, this quarter up 12%. Enter 12 and 450,000,000 for 504,000,000.

Example 4 — 15% commission

Pick "X% of Y", enter 15 and 12,000,000, and you get 1,800,000. Fifteen percent of 12 million is 1.8 million, not 180 thousand.

When to use it, and when not to

Worth using

  • Tax, commission, interest and discount calculations.
  • Converting a price change into a percentage between two reporting periods.
  • Splitting money by ratio, or working out grade percentages.
  • Any quick share of a total when you would rather not open a calculator.

Not worth it

  • Compound interest over many periods. This applies a percentage once; compounding needs its own formula.
  • Long-run growth comparisons, where inflation and a shifting mix change the picture.
  • Percentage point versus percent change. Going from 4 to 5 is a 1-point gain and also 25%, and mixing them up is common.

How to calculate

  1. Choose the type of calculation you need.
  2. Enter the values in the matching fields.
  3. Press Calculate.
  4. Press Copy result if you need it elsewhere.

Frequently asked questions

What is the percentage formula?

(percentage value / 100) × original value. To find what percent a number represents, divide it by the original value and multiply by 100.

How is a 20% discount different from subtracting 20?

A 20% discount on 1,000 leaves 800, while subtracting 20 means removing 20 units and leaving 999,980.

Are results rounded?

Yes, results are rounded to a readable number of decimals.