Percentage Calculator
Computes X% of Y and what-percent-of-what (X is what % of Y) in two side-by-side panels with precise decimal arithmetic. Essential for everyday math — tips, discounts, tax rates, grade scores, and statistical comparisons where quick percentage answers are needed. Numbers never leave your device — every calculation runs locally in your browser.
How to Use the Percentage Calculator
Similar Tools You Might Need
See allFinal Grade Calculator
Compute your overall course percentage from comma-separated assignment grades and their matching weights — Exam Heavy presets included. Numbers never leave your device — every calculation runs locally in your browser.
GPA Calculator
Compute semester GPA from course grades and credit hours with credit-weighted math on the standard 4.0 scale — quick academic snapshot. See what straight B's earn — free, local, no signup.
Grade Calculator
Convert a single course percentage into its letter grade on the built-in plus/minus scale — see that an 85 earns a B instantly. Free, local, no signup.
Time Converter
Convert between time units including seconds, minutes, hours, days, weeks, months, and years with precise decimal results. Input never leaves your device — everything runs locally in your browser.
GST Calculator
Computes GST-inclusive and GST-exclusive amounts for Indian tax slabs (5%, 12%, 18%, 28%) with net, GST value, and total shown.
Frequently Asked Questions
What can it compute?
Two modes: X% of Y (20% of ₹1,500 = ₹300) and what-percent-of-what (45 is 25% of 180). Covers tips, discounts, tax, and grade math.
How do I reverse a discount?
A 20%-off price of ₹800 means original = 800 ÷ 0.80 = ₹1,000 — not 800 × 1.20 (₹960). Always divide by (1 − rate) to undo a percentage decrease.
Why do successive percentages not add?
10% off then 10% off again is 19% total, not 20%: ₹100 → ₹90 → ₹81. Each discount applies to the reduced base — chain them by hand by feeding each result back in as the next Y.
How precise are the results?
Full decimal precision (e.g., 33.333…% for 1/3), rounded for display only. Useful for tax and statistical comparisons where rounding early compounds errors.
Is my input stored?
No. All computation runs locally in your browser. Nothing is transmitted or stored.
Related Calculator Tools
Percentage Difference Calculator
Calculate the percentage difference between any two numbers. Useful for comparing data sets, prices, and measurements. Numbers never leave your device — every calculation runs locally in your browser.
Ratio Calculator
Simplify any two-number ratio to lowest terms via GCD — paint mixes, screen sizes, shares. Reduce 150:225 to 2:3 in one pass — free, runs locally.
Rounding Calculator
Round numbers using 5 modes: round half up, banker's rounding, floor, ceil, and truncate. Shows step-by-step explanation with the digit being rounded. Numbers never leave your device — every calculation runs locally in your browser.
Last updated October 2026