inicio/productivity/percentage

Percentage Calculator

Calculate percentages, percentage change, and what percent one number is of another

100% client-side — your data never leaves your browser

Cómo usar Calculadora de Porcentajes

  1. 1

    Choose a calculation mode

    Select 'X% of Y', 'X is what % of Y', or 'Percentage change from X to Y'.

  2. 2

    Enter your numbers

    Fill in the two number fields. Results update as you type — no submit button needed.

  3. 3

    Read the result and formula

    The answer is displayed alongside the formula used, so you can verify the math or learn the technique.

¿Qué es Percentage Calculator?

Solve any percentage question instantly: find X% of a number, calculate what percentage one number is of another, or compute the percentage change between two values. Each result includes the formula used so you can understand the math. Runs entirely in your browser — no server, no account, no data collection.

¿Por qué usar Percentage Calculator?

  • Three calculation modes cover virtually every percentage question you will encounter.
  • Shows the formula alongside the answer — learn the math instead of just getting a number.
  • Results update in real time as you type, with no page reload or button click.
  • Handles both positive and negative percentage changes correctly.
  • Completely private — your numbers are processed locally and never transmitted.

Preguntas frecuentes

What percentage calculations does this tool support?
Three modes: (1) What is X% of Y — for discounts, tips, and taxes; (2) X is what percent of Y — for grades and proportions; (3) Percentage change from X to Y — for financial changes and growth rates.
How do I calculate a discount price?
Use 'What is X% of Y' mode. Enter the discount percentage and the original price. Subtract the result from the original price to get the sale price. For example, 25% of $80 = $20, so the sale price is $60.
What is the difference between percent and percentage points?
Percent is a relative measure; percentage points are an absolute difference. If a rate goes from 5% to 8%, the increase is 3 percentage points but a 60% relative increase. Confusing the two is one of the most common errors in financial reporting.
Is my data safe?
Yes. All processing happens entirely in your browser. Your data never leaves your device and is never uploaded to any server.

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Casos de uso de Percentage Calculator

Shopping and discounts

Calculate the actual dollar amount of a 30% off sale, figure out how much you save, or compute the final price after tax.

Test scores and grades

Determine what percentage you scored on an exam — for example, 37 correct out of 50 questions equals what percent?

Financial reporting

Calculate year-over-year revenue growth, margin changes, or return on investment as a percentage for presentations and reports.

Tip calculation

Figure out a 15%, 18%, or 20% tip on a restaurant bill without pulling out a separate tip calculator app.

Consejos y buenas prácticas

  • 💡To reverse a discount and find the original price, divide the sale price by (1 minus the discount rate). For example, $72 after a 10% discount means the original was $72 / 0.90 = $80.
  • 💡When comparing two percentages, always clarify whether you mean the absolute difference (percentage points) or the relative change (percent change). The distinction matters enormously in finance.
  • 💡Use the percentage-change mode to quickly check if a product's 'was / now' pricing adds up — enter the old and new prices to see the real discount percentage.

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