Free Percentage Calculator Online

Solve common percentage calculations in one place.

Percentage Calculator

Run percentage-of, reverse-percent, percent-change, increase, and decrease calculations.

🔒 Processes data locally in your browser — input isn’t uploaded or stored.

Why Use This Tool

This percentage calculator helps with pricing, budgeting, and reporting by handling common formulas like percent of a number, reverse percentage, and percent change in one place. Common next steps include Discount Calculator and Tip Calculator.

What This Tool Does

Enter your values, choose the percentage mode, and review the result.

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How to Use

  1. Choose a formula mode: percentage-of, reverse percentage, percent change, increase, or decrease.
  2. Enter values A and B, then set your preferred decimal precision.
  3. Run calculation and copy the formula breakdown plus result.

Examples

  • What is 15% of 240? Use percent-of mode with A=15 and B=240.
  • How much did sales grow from 80 to 125? Use percent-change mode.
  • What original value gives 30 when 25% is applied? Use reverse-percentage mode.

Common Mistakes

  • Using percent change when you actually need percentage-of mode.
  • Entering values from different units or currencies in the same formula.
  • Forgetting whether your input is already tax-inclusive or discount-adjusted.

Workflow Notes

  • Use increase/decrease modes for pricing, forecasting, and budget adjustments.
  • Use reverse-percentage mode to back-calculate rates from known totals.
  • Keep units consistent (currency, quantity, etc.) before comparing values.

Common Use Cases

  • Check discount impact before purchase decisions.
  • Measure growth and decline in dashboards or monthly reports.
  • Back-calculate rates from known totals in finance and operations.

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FAQ

What formula modes are included in this percentage calculator?

This page supports percentage-of, reverse percentage, percent change, increase by percent, and decrease by percent.

Can I control decimal precision?

Yes. Set decimal precision before running the calculation to match reporting requirements.

Does the tool support negative values?

Yes. Negative values are supported where mathematically valid for the selected formula mode.

Which mode should I use for growth over time?

Use percent-change mode when comparing start and end values from two periods.

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