ToolNestFree Online Percentage Calculator
Percentages trip everyone up — tips, discounts, grades, growth rates. Our free percentage calculator handles the three calculations people actually need: X% of Y, X is what percent of Y, and percentage increase/decrease — with the formula shown so you learn as you go.
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✓ Free forever · ✓ No signup · ✓ Runs in your browser — your data never leaves your device.
How to Use the Percentage Calculator
- Pick the calculation you need from the dropdown.
- Enter your X and Y values.
- Click Calculate — the answer and the formula appear instantly.
- Switch modes to compare, e.g. discount vs. markup.
Why Use Our Percentage Calculator?
- Three core modes — percent-of, percent-is, and percent-change.
- Shows the formula — so you understand the math, not just the answer.
- Handles negatives & decimals — correct for losses, refunds, and growth.
- Free & instant — no signup, works on mobile.
Frequently Asked Questions
How do I calculate X% of Y?
Multiply: (X ÷ 100) × Y. So 20% of 150 = 0.20 × 150 = 30.
How do I find what percent X is of Y?
Divide: (X ÷ Y) × 100. So 30 is what percent of 150? (30 ÷ 150) × 100 = 20%.
How is percentage increase calculated?
((New − Old) ÷ Old) × 100. A price rising from $50 to $65 is a 30% increase.
What's the difference between percent and percentage points?
A rise from 20% to 25% is a 5-percentage-point increase, but a 25% relative increase. Mixing them up is the classic stats mistake.
Is this calculator free?
Yes — free forever, no account needed.