Percentage Calculator
The Percentage Calculator solves all types of percentage problems in seconds. Find what percent of a number is, calculate percentage increase or decrease, or find the original value from a percentage.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Percentage Calculator
Calculate Percentages Instantly
📐 Formula & Method
Percentage of a Number
To find X% of Y, divide X by 100 and multiply by Y.
Percentage Change
Calculate the percentage increase or decrease between two values.
📋 How to Use
-
1
Select the type of percentage calculation you need.
-
2
Enter the values in the X and Y fields.
-
3
Click "Calculate" to get instant results.
-
4
View the formula used and the step-by-step solution.
Understanding Percentage Calculations
A percentage is a dimensionless number expressed as a fraction of 100. The word "percent" comes from Latin "per centum," meaning "by the hundred." Percentages are used everywhere — from discounts and tax rates to exam scores and statistics.
There are several types of percentage problems: finding a percentage of a number, finding what percentage one number is of another, and calculating percentage change between values.
🔬 Methodology & Accuracy
Formula: Uses the standard mathematical formula shown in the Formula & Method section above. All computations run client-side in your browser — no data is sent to our servers.
Data sources: Tax bands, contribution limits and regulatory rates are taken from official US (IRS, SSA) and UK (HMRC, gov.uk) publications for the current tax year, and updated when bands change.
Last reviewed: June 2026 · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.