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Percentage Increase Calculator

Two jobs in one form: measure how much a value grew in percent, or add a percentage to a number and see the new total.

Try:

Answer

Enter your numbers or pick an example — the answer and the steps appear here instantly.

Two modes

  • Increase between two values

    Give the starting value and the value it grew to. 40 to 50 is a rise of 10, and 10 ÷ 40 = 25%. If the new value is smaller, the result comes out negative and is explained as a decrease.

  • Increase a value by X%

    Enter a starting value and a percent. A 15% increase uses the growth factor 1 + 15/100 = 1.15, so 40 becomes 46, with 6 added on top.

Using the calculator

  1. Pick a mode

    In the What to do menu, choose between measuring an increase and applying one.

  2. Fill in the values

    Give the original value and either the new value or the percent. Fractions, decimals, a decimal comma and negative numbers are all accepted.

  3. Get the answer

    Press Calculate for the result, the labeled details (growth factor, amount added or difference) and a numbered outline. It is free and needs no login.

  4. Go further if you like

    “Explain step by step” hands the same problem over to the AI Math Solver, which writes out the reasoning; check it against the outline, since AI can be wrong. “Ask a follow-up” then carries the conversation into AI Chat.

Percentage increase by hand: four things worth knowing

  • Measuring a rise

    Subtract, then divide by the original: (50 − 40) ÷ 40 = 0.25 = 25%. Always divide by the starting value, never by the new one.

  • Applying a rise in one step

    Multiply by the growth factor instead of finding the increase separately. 40 × 1.15 = 46 gives the same result as 40 + 0.15 × 40.

  • Undoing an increase

    To find a value before a 15% rise, divide by the growth factor: 138 ÷ 1.15 = 120. Subtracting 15% of 138 instead gives 117.3, which is wrong.

  • Increases compound

    Two 10% rises multiply: 1.1 × 1.1 = 1.21, a 21% increase overall rather than 20%. A 100% increase doubles a value, and a 200% increase triples it.

Frequently asked questions

The result is negative, −20% for 50 to 40, and the page states that this is a decrease. For changes in either direction, the percent change calculator reports the same number.

Select “Increase a value by a percentage”, enter the number and the percent, and press Calculate. You get the new value, the amount added and the growth factor, e.g. 1.08 for an 8% rise.

Yes. 2.5% gives a growth factor of 1.025, and 150% gives 2.5, so 40 increased by 150% becomes 100.

Most are exact, because the math runs on fractions rather than floating-point numbers. A result with an endless decimal is shown rounded, prefixed with ≈ and tagged Rounded; 30 to 40, for example, is a 33.3…% increase.

Pro plans* cover a written AI explanation (*fair use: up to 300 runs per day for the writing, study and code tools together); with no plan it takes 2 credits. Anyone not signed in may preview its opening at no charge, and the calculator never costs anything.

The outline is meant for learning and checking, not for handing in. Follow your course's rules on AI and calculator use, and write the solution in your own words when you are asked to show work.

Related percent tools

Find or apply an increase

Measure growth between two numbers or raise a value by any percent, with the growth factor in view.

Calculate increase
  • Two modes in one form
  • Growth factor and amount added
  • Decreases explained, not hidden