Percentage Calculator — what it does
Answers the three percentage questions people actually ask: what is X% of Y, X is what percent of Y, and what is the percentage change from one number to another. Built for marks, discounts, tax rates and growth numbers — the everyday cases where opening a spreadsheet feels heavier than the question.
How to use Percentage Calculator
- Pick the mode: 'X% of Y', 'X is what % of Y', or 'percentage change'.
- Enter the two numbers.
- Read the result, with the formula shown underneath so you can verify it.
- For percentage change, order matters: the second number is the baseline the change is measured against.
- Chain calculations by copying a result into the next mode.
Worked example: a discount plus tax
A ₹2,400 item is 15% off, then 18% GST is added. Mode 1: 15% of 2400 = ₹360, so the price is ₹2,040. Mode 1 again: 18% of 2040 = ₹367.20, final price ₹2,407.20. Note the trap it avoids: 15% off then 18% on is NOT a 3% net gain, because the second percentage applies to a different base — the two-step calculation shows the real number.
At a glance
| Modes | X% of Y · X as % of Y · % increase/decrease |
|---|---|
| Shows work | The formula and substitution are displayed, not just the answer |
| Precision | Full decimal precision; round only at the end for money |
| Privacy | All arithmetic in the browser — no inputs leave the device |
| Limits | Percentage-point vs percent distinction is yours to make; see FAQ |
Frequently asked questions
- What is Percentage Calculator?
- Calculate percentages, increases, decreases and ratios instantly.
- Is Percentage Calculator free to use?
- Yes — Percentage Calculator is free to use, with no sign-up, no install and no account.
- Does Percentage Calculator upload or store my data?
- No — Percentage Calculator runs entirely in your browser, so your text, files and results never leave your device.
- Do I need to install anything to use Percentage Calculator?
- No — it works in any modern browser (Chrome, Edge, Firefox, Safari) with no downloads, accounts or plugins.
- What is the difference between a percent change and percentage points?
- If a rate moves from 8% to 10%, that is a 2 percentage-point rise but a 25% relative increase (2/8). News and finance mean different things by 'rose 2' — this tool computes the relative change, so read its output as the 25% kind.
- Why is a 50% loss not undone by a 50% gain?
- Because the bases differ: 100 → 50 is −50%, but 50 → 100 is +100%. Percentage change is always relative to where you start, which is exactly what the 'change' mode encodes.
- Can I use it for marks with different weightages?
- For weighted averages, compute each part's percentage separately and multiply by its weight — the tool gives you each piece; combining them is one more line by hand.