Percentage Calculator, 5 modes in one tool
What is X% of Y? What percent is X of Y? Percentage increase? Discount? Tip? VAT? All five percentage questions in one page. Live result as you type, step-by-step formula shown, no sign-up.
- 5 calculation modes
- Live result, no button
- Step-by-step formula
- Works offline
Result
—
Enter values to see a result
Calculated on your device. Nothing is uploaded or saved. How we keep it private
- 100% Secure
- Instant Result
- 5 Modes
- No Sign-up
- Step-by-step
- History
Percentage formulas cheat sheet
Every formula the tool uses, with a worked example. Bookmark this if you do percentage math often.
| Question | Formula | Example |
|---|---|---|
| What is X% of Y? | (X / 100) x Y | What is 20% of 150? -> (20 / 100) x 150 = 30 |
| X is what percent of Y? | (X / Y) x 100 | 30 is what % of 150? -> (30 / 150) x 100 = 20% |
| X is Y% of what number? | (X / Y) x 100 | 30 is 20% of what? -> (30 / 20) x 100 = 150 |
| Percentage change from X to Y | ((Y - X) / |X|) x 100 | From 100 to 120 -> ((120 - 100) / 100) x 100 = +20% |
| Add X% to Y | Y + (X / 100 x Y) | Add 18% to 250 -> 250 + 45 = 295 |
| Subtract X% from Y | Y - (X / 100 x Y) | Subtract 30% from 80 -> 80 - 24 = 56 |
Common percentages at a glance
The most frequently looked-up values. The tool computes any of these instantly, this table is a quick reference.
| Percent | of 100 | of 500 | of 1,000 | of 2,000 |
|---|---|---|---|---|
| 5% | 5 | 25 | 50 | 100 |
| 10% | 10 | 50 | 100 | 200 |
| 15% | 15 | 75 | 150 | 300 |
| 20% | 20 | 100 | 200 | 400 |
| 25% | 25 | 125 | 250 | 500 |
| 30% | 30 | 150 | 300 | 600 |
| 40% | 40 | 200 | 400 | 800 |
| 50% | 50 | 250 | 500 | 1000 |
| 75% | 75 | 375 | 750 | 1500 |
Why this is the best percentage calculator
Everything runs on your device, faster, cleaner and free from the usual calculator-site trade-offs.
| Feature | TToolDeck | Calculator.net | RapidTables |
|---|---|---|---|
| No sign-up or email | Yes | Partial | No |
| No ads blocking the inputs | Yes | No | No |
| Five calculation modes in one tool | Yes | Partial | Partial |
| Step-by-step formula shown | Yes | No | No |
| Live result as you type | Yes | Yes | Yes |
| History of recent calculations | Yes | No | No |
| Quick 5/10/20/25% buttons | Yes | Partial | No |
| Works offline after first load | Yes | No | No |
| No popups, no signup wall | Yes | No | No |
| Copy result to clipboard | Yes | Partial | Yes |
Comparison reflects publicly available information at the time of writing. Features may change. Representative examples of common patterns.
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How it works
- 1
Pick the mode
Choose from five common percentage questions: X% of Y, X is what % of Y, X is Y% of what, increase/decrease, or add/subtract percent.
- 2
Enter two numbers
Type into the two fields. The result appears instantly, no button to press. Use quick presets for common percentages.
- 3
See the math
Every result comes with the step-by-step formula. Copy the result or check it against your own calculation.
Everything you get for free
Five calculators in one
What is X% of Y. X is what % of Y. X is Y% of what. Percentage increase or decrease between two numbers. Add or subtract a percent. Everything you actually need is here, not scattered across five different pages.
Live result, no button
The answer updates as you type. No Calculate click, no page refresh. Type a number in either field and the result is there before you finish.
Step-by-step formula
Every result comes with the math shown: "20% of 150 = (20 / 100) x 150 = 30". Useful when you need to show your work for homework, a report or a spreadsheet check.
Percentage change with direction
From 100 to 120 is +20% increase. From 100 to 80 is -20% decrease. The tool names the direction and shows the sign, so you never have to guess whether a result is up or down.
Quick preset buttons
The most common percentages: 5, 10, 15, 20, 25, 30, 40, 50, 75 are one tap away. Faster than typing for tips, tax, discounts and markup.
Recent history
The last 8 calculations are kept (in your browser only) so you can glance back at what you just worked out. No account, no cloud, no log.
Accurate decimals
Results are shown with up to four decimals, and very large numbers switch to scientific notation. No rounding errors, no 0.30000000000004 surprises.
No sign-up, no ads blocking inputs
Open the tool and use it. No account, no email, no popups, no ad that covers the input fields. AdSense-friendly but user-respectful.
What people use it for
Tips at restaurants
Bill is 45, tip 15%, enter 15 and 45 in the first mode. Result: 6.75. Add to the bill for the total.
Discounts while shopping
A shirt is 60 with 25% off, enter 25 and 60. Result 15 saved, so 45 is the final price. Try it before you buy.
Tax and VAT calculations
You made 250 and VAT is 18%, Add/Subtract mode: add 18% to 250 = 295. Or work backwards from a VAT-inclusive price.
Report changes and growth
Revenue went from 120K to 180K. Change mode: +50% increase. Or profit fell from 80 to 60: -25% decrease. Perfect for dashboards and business updates.
Grades and exam scores
You scored 42 out of 50, is-what-percent mode: 42 is 84% of 50. Works for any test, quiz, or assignment score.
Markup and margin
Product cost 40, sold for 52, change mode gives +30% markup. Or set a target margin: 40 is ?% of 52 gives 76.9% margin.
Questions people ask
What is the formula for percentage?
The basic formula is: percentage = (part / whole) x 100. For example, 30 out of 150 is (30 / 150) x 100 = 20%. To find a percentage OF a number: (percent / 100) x number. Both formulas are shown step-by-step for every calculation in the tool.
How do I calculate a percentage increase or decrease?
Use the Change mode. Enter the original value in the first field and the new value in the second. The result is (new - old) / |old| x 100. A positive result means an increase, negative means a decrease. Example: from 100 to 120 is +20%. From 100 to 80 is -20%.
What is the difference between percent and percentage points?
If a rate goes from 5% to 7%, that is a 2 percentage point increase, but it is a 40% relative increase. Percentage points measure absolute difference between two percentages. Percent change measures the relative difference. Both interpretations are valid; the context decides which is correct. Our tool computes percent change; for percentage points just subtract the two values.
How do I calculate a discount?
Use the Add / Sub % mode with Subtract. If a shirt is 60 with 25% off, enter 25 in the percentage field and 60 in the number field, then pick Subtract %. Result: 45 (the price after the discount). The amount saved is 15.
How do I calculate a tip?
Use X% of Y. Bill is 45, tip 15%, enter 15 and 45 in the first mode. Result 6.75. For 20% tip on the same bill: enter 20 and 45 gives 9. Common restaurant tips (15%, 18%, 20%) are one tap away with the preset buttons.
How do I work out VAT or sales tax?
To ADD tax to a net price: use Add / Sub % with Add. Price 250, VAT 18% gives 295. To work out the tax INCLUDED in a gross price: use Change mode. Gross 295, net 250, the difference is 18%. Alternatively, X is what % of Y tells you the tax rate when you only know the amounts.
What does X is Y% of what number mean?
This mode finds the original total when you know a part and its percentage. Example: 30 is 20% of what number? Answer: 150. Formula: (part / percent) x 100. Useful when you know the discount amount and the discount rate but not the original price.
Why does the result show 4 decimals?
Many real-world percentages do not divide evenly (like 1/3 = 33.3333%). Showing 4 decimals means you do not lose precision. You can round it yourself for display, for example 33.33% or 33% depending on the context.
Is there a maximum or minimum input?
No hard limit, but the result shows in scientific notation above about 10^12 and precision drops for extremely large numbers, as with any calculator. For everyday numbers (prices, salaries, exam scores, statistics) the accuracy is exact up to 4 decimals.
Is my data saved anywhere?
No. The calculation happens in your browser. The only thing stored is a short history of your recent calculations, and only in your browser session, gone when you close the tab. Nothing is sent to any server.
Does it work on mobile?
Yes. The layout is designed for phone screens first. Tap the input, type, and the result appears live. The preset buttons are large enough to tap comfortably.
Does it work offline?
Yes. Once the page has loaded, everything is done in your browser. You can switch off Wi-Fi and keep using it.
Your calculations stay on your device
Every calculation happens in your browser. Your history is kept only in your session, and disappears when you close the tab. Nothing is sent to a server, no account is required, and there is no way for us to see what numbers you entered. Read how we keep it private.