Percentage Calculator
Instant results as you type — no calculate button, ever.
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Frequently Asked Questions
How do I calculate my percent?
To calculate a percentage, use the formula: (Part ÷ Whole) × 100. For example, if you scored 45 out of 60, your percentage is (45 ÷ 60) × 100 = 75%. Enter the two numbers in the "X is what % of Y?" field above for an instant result.
How do I calculate the percentage of a total?
Divide the part by the total and multiply by 100. Formula: (Part ÷ Total) × 100 = %. Example: 40 out of 200 = (40 ÷ 200) × 100 = 20%. Use the Basic % calculator above — it gives you all three percentage question types simultaneously.
What is X% of a number — and how do I calculate it?
Multiply the number by the percentage divided by 100. Formula: Number × (% ÷ 100) = Result. Example: 15% of 300 = 300 × 0.15 = 45. The "What is X% of Y?" section above calculates this live as you type.
How do I calculate a percentage increase?
Use the formula: ((New Value − Old Value) ÷ Old Value) × 100. If a price went from $80 to $100, the increase is ((100 − 80) ÷ 80) × 100 = 25%. Use the % Change Calculator for instant results.
What is the difference between a percentage and a percentage point?
A percentage point is the arithmetic difference between two percentages. For example, going from 10% to 15% is a 5 percentage-point increase — but a 50% relative increase. Percentage points measure absolute change; percentages measure relative change.
How do I find the original number before a percentage was applied?
Use the "X is Y% of what?" section in the Basic calculator. The formula is: Original = Part ÷ (Percentage ÷ 100). Example: 45 is 15% of what? → 45 ÷ 0.15 = 300.
Can I use this percentage calculator on my phone?
Yes — PercentCal is fully mobile-optimized and works instantly in any browser. No app install, no sign-up, and no "Calculate" button to press. Results appear live as you type.
Everything You Can Do With a Percentage Calculator
A percentage calculator is one of the most useful math tools you can have at your fingertips. Whether you're figuring out a discount at the store, calculating a tip at a restaurant, checking your grade on a test, or working out a salary raise, percentages are everywhere in everyday life. PercentCal brings all of these calculations together in one fast, free, online percentage calculator — no sign-up, no button clicks, just instant live results as you type.
Basic Percentage Calculations
The core of any online percentage calculator is the ability to answer three fundamental questions. First: "What is X% of Y?" — for example, what is 15% of $200? Answer: $30. Second: "X is what percent of Y?" — for example, 45 is what percent of 300? Answer: 15%. Third: "X is Y% of what number?" — useful when you know a part and its percentage but need to find the whole. All three are available simultaneously in Basic mode so you can solve any percentage problem without switching screens.
Percentage Change, Increase & Decrease
The increase percentage calculator and % change calculator built into PercentCal shows you exactly how much a value has grown or shrunk, colour-coded green for increases and red for decreases. This is invaluable for tracking prices, investment returns, or statistics over time. The formula is: ((New − Old) ÷ Old) × 100. A common use case is a salary increase percentage calculator — if your salary went from $55,000 to $60,000, that's a 9.09% raise. Simply enter the two values and the result appears instantly.
Discount Calculator
Shopping smarter starts with knowing exactly how much you're saving. The discount percentage calculator on PercentCal takes an original price and a discount percentage and immediately tells you the final price and the dollar amount you're saving. Is that $120 jacket marked 35% off actually worth it? Enter the numbers and find out in under a second — no mental math required.
Tip Calculator
Splitting the check at a restaurant has never been easier. The tip calculator lets you enter your bill amount, choose a tip percentage (15%, 18%, 20%, or any custom amount), and split the total between any number of people. You get the tip amount, the full total, and the per-person share — all live. It's the fastest tip calculator you'll find, and it works seamlessly on your phone right from the browser.
Grade & Marks Percentage Calculator
Students and teachers love the grade percentage calculator. Enter the points you scored and the total points available, and PercentCal instantly converts it to a percentage. It covers everything from a quick test percentage calculator check ("I got 43 out of 50 — what's that?") to a full school percentage calculator for tracking cumulative marks across multiple subjects. The marks percentage calculator is especially handy when coursework uses different point scales — just enter any two numbers and get your grade percentage right away.
Win Percentage & Average Percentage
A win percentage calculator works exactly like a marks percentage calculator: divide wins by total games and multiply by 100. If your team won 18 out of 25 games, that's 72% — enter 18 and 25 in the "X is what % of Y?" section and you're done. For an average percentage calculator, you can calculate each percentage individually and average them, or simply add up all scores and total points for a weighted average. PercentCal handles both approaches with ease.
Tax Calculator
The sales tax calculator makes it easy to add any tax rate to a price. Enter a pre-tax price and your local sales tax rate, and instantly see the total amount and exactly how much tax you're paying. Quick-pick buttons for common US rates (5%, 8%, 10%, 13%) are built right in so you don't even have to look up your state's rate.
Why Use PercentCal?
Unlike a basic calculator app or a generic search result, PercentCal is purpose-built for percentage math. Every calculation updates the moment you type — there's no "Calculate" button to click and no page to reload. The clean, distraction-free design works on every device, and all six tools (basic percentage, % change, discount, tax, tip, and grade) are available from a single tab bar. It's the only percentage calculator online you'll ever need to bookmark.