Must-have
Percentage Calculator
How to use this percentage calculator
- Enter the requested values in the calculator.
- Review the result immediately below the fields.
- Use the explanation and example below to check how the result was obtained.
Method and formula
Multiply the number by the percentage divided by 100. For percentage change, subtract the old value from the new value, divide by the absolute old value, and multiply by 100.
Worked example
A 15% tip on $80 is 80 × 0.15 = $12. A price rising from $120 to $138 has changed by (138 − 120) ÷ 120 × 100 = 15%.
What the result does not include
Percentage change is undefined when the starting value is zero. Keep extra decimal places during the calculation and round only the final result.
Frequently asked questions
Are the calculations saved?
No. The calculation runs in your browser. This site does not receive or store the numbers and dates entered into a calculator.
Why can another calculator show a slightly different result?
Results can differ because of rounding, input units, timing assumptions, or extra fees and variables. Keep full precision until the final step and compare the assumptions used by each source.
Can I use this result for an official decision?
Use it as an educational estimate and a way to check your own arithmetic. For medical, financial, academic, or legal decisions, confirm the result with the relevant professional or institution.