Calculate percentages instantly — find X% of any number, determine what percent one value is of another, or compute percentage increase and decrease. Free, accurate, and no sign-up required.
Three calculation modes for every percentage problem you encounter
Type your numbers into the labeled fields. Each mode shows only the inputs it needs. The calculator automatically applies the correct percentage formula — no manual setup required.
Click Calculate to see your answer with a plain-English explanation of how it was derived. Copy the result to your clipboard with one click for use in reports, spreadsheets, or messages.
Each of the three calculation modes answers a different question. Here is what each result means and how to interpret it.
Percentages express numbers as parts of 100 — a universal way to compare proportions across different scales. The word "percent" comes from the Latin per centum, meaning "by the hundred." Whether you are comparing exam scores, tracking price changes, or calculating a tip, percentages put numbers into a standard proportion that is easy to understand and compare.
One of the most important things to understand about percentages is the distinction between a percentage and a percentage point. If an interest rate rises from 4% to 5%, it has increased by 1 percentage point — but by 25% in relative terms. Confusing these two is one of the most common errors in financial and statistical communication.
Step-by-step walkthrough of all three percentage formulas — with real numbers.
This is the most common percentage question. You know the percentage and the whole; you need the part.
Result = (Percentage ÷ 100) × Number
Worked Example: 20% off a $149 item
Step 1: Divide 20 by 100 → 0.20
Step 2: Multiply by $149 → 0.20 × $149 = $29.80 (the discount amount)
Step 3: Subtract from original → $149 − $29.80 = $119.20 (the sale price)
This works for any discount, tip, or tax calculation. For a 15% restaurant tip on a $64 bill: (15 ÷ 100) × $64 = $9.60 tip.
You know the part and the whole; you need to express the relationship as a percentage. This is how you calculate test scores, market share, or completion ratios.
Percentage = (Part ÷ Whole) × 100
Worked Example: A student scores 42 out of 60 on a test
Step 1: Divide the score by the total → 42 ÷ 60 = 0.70
Step 2: Multiply by 100 → 0.70 × 100 = 70%
Another example: A company has 1,250 customers out of a total market of 5,000. Market share = (1,250 ÷ 5,000) × 100 = 25%.
Use this when you want to measure how much something has changed relative to its starting value. Positive results are increases; negative results are decreases.
% Change = ((New Value − Old Value) ÷ Old Value) × 100
Worked Example: Business revenue rises from $500,000 to $620,000
Step 1: Subtract old from new → $620,000 − $500,000 = $120,000
Step 2: Divide by the old value → $120,000 ÷ $500,000 = 0.24
Step 3: Multiply by 100 → 0.24 × 100 = +24% growth
For a decrease: If a stock price falls from $85 to $68, the change = ((68 − 85) ÷ 85) × 100 = −20% (a 20% decline).
Practical scenarios where this calculator helps most — with real numbers you can follow.
Enter the discount percentage as X and the original price as Y in "What is X% of Y?" mode. The result is your savings amount. Subtract it from the original price for the final sale price. Example: 30% off a $219 jacket → savings = $65.70 → sale price = $153.30. For stacked discounts (e.g., 20% off, then an extra 10%), calculate them sequentially — not additively — because the second discount applies to the already-reduced price.
Use "What is X% of Y?" to find the tip amount. For an 18% tip on a $73 dinner: 18% of $73 = $13.14. Add to the bill for a total of $86.14. For sales tax, the process is identical. In California, the base state sales tax is 7.25%, but many counties add local rates — Los Angeles County total is 10.25%. On a $200 purchase: 10.25% of $200 = $20.50 in tax, making the total $220.50.
Use the "% Increase/Decrease" mode to measure year-over-year growth, quarterly change, or any two-period comparison. Enter the earlier period as Original Value and the later period as New Value. A quarterly growth from $1.2M to $1.38M = ((1,380,000 − 1,200,000) ÷ 1,200,000) × 100 = 15% growth. If you need to find a target value — for example, what revenue represents 20% growth from $1.2M — use "What is X% of Y?" to find 20% of $1,200,000 = $240,000 increase, then add: $1,200,000 + $240,000 = $1,440,000.
Convert raw scores to percentages using "X is what % of Y?" Enter the points earned as X and total possible points as Y. A score of 76 out of 95 = (76 ÷ 95) × 100 = 80%. You can also use the percentage change mode to track improvement: if a student's score rose from 68% to 82%, the improvement = ((82 − 68) ÷ 68) × 100 = 20.6% relative improvement — a meaningful distinction from simply saying "14 percentage points higher."
For fast mental calculations, use the 10% anchor method. Find 10% of any number by moving the decimal point one place left. For 10% of $340 → $34. Then scale: 20% = 34 × 2 = $68; 5% = $34 ÷ 2 = $17; 15% = $34 + $17 = $51; 1% = $3.40. This works reliably for tip calculations and quick discount estimates when you do not have a calculator handy. For precise work — finance, tax, or science — always use the calculator above.
Percentage error measures how far an estimated or measured value is from a known actual value. Formula: (|Estimated − Actual| ÷ Actual) × 100. If you measure a chemical solution as 48.5 mL but the actual volume is 50 mL: (|48.5 − 50| ÷ 50) × 100 = 3% error. You can calculate this using the "% Increase/Decrease" mode — enter the actual value as Original and the estimated value as New, then take the absolute value of the result. Percentage error is widely used in chemistry, physics, and engineering to assess measurement accuracy and instrument precision.
One of the most common sources of confusion in financial and statistical communication.
When two percentages change, you can describe the difference in two completely different ways — and both are technically correct but mean very different things.
The simple arithmetic difference between two percentages. If a tax rate increases from 20% to 25%, it has gone up 5 percentage points.
Used when: comparing two rates directly; reporting poll results; describing absolute changes in rates.
The relative change compared to the starting value. A move from 20% to 25% is ((25 − 20) ÷ 20) × 100 = 25% increase in relative terms.
Used when: measuring growth rate; comparing the magnitude of changes; expressing how much something has grown or shrunk.
Suppose a mortgage rate rises from 4.5% to 6.0%. A lender might say this is "1.5 percentage points higher" — which is technically accurate. But in relative terms, it is ((6.0 − 4.5) ÷ 4.5) × 100 = 33.3% more expensive. On a $400,000 loan over 30 years, this represents thousands of dollars in additional interest. The percentage point description understates the financial impact compared to the relative percentage change.
In journalism, political reporting, and medical research, percentage points are often preferred when describing changes in rates (e.g., unemployment, approval ratings, infection rates). Percentage change is used for quantities and absolute numbers. Understanding which measure is being used is critical for correctly interpreting what you read.
Use this table to quickly estimate percentage values without a calculator. Values are rounded for mental math convenience.
| Number | 10% | 15% | 20% | 25% |
|---|---|---|---|---|
| $50 | $5 | $7.50 | $10 | $12.50 |
| $100 | $10 | $15 | $20 | $25 |
| $200 | $20 | $30 | $40 | $50 |
| $500 | $50 | $75 | $100 | $125 |
| $1,000 | $100 | $150 | $200 | $250 |
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Common questions about percentage calculations, formulas, and real-world use cases.
Use the formula: ((New Value − Old Value) ÷ Old Value) × 100. If the result is positive, it is an increase; if negative, it is a decrease. Example: a price rising from $80 to $100 → ((100 − 80) ÷ 80) × 100 = 25% increase. A price falling from $100 to $80 → ((80 − 100) ÷ 100) × 100 = −20% decrease.
Multiply the number by the percentage and divide by 100. Formula: Result = (Percentage ÷ 100) × Number. Example: 15% of 240 = (15 ÷ 100) × 240 = 36. This is the same as multiplying 240 by 0.15. Use the "What is X% of Y?" mode in this calculator for instant results.
Divide the part by the whole and multiply by 100. Formula: Percentage = (Part ÷ Whole) × 100. Example: 45 of 180 = (45 ÷ 180) × 100 = 25%. Another example: a student scoring 42 out of 60 = (42 ÷ 60) × 100 = 70%. Use the "X is what % of Y?" mode in this calculator.
Enter 20 as X and the original price as Y in "What is X% of Y?" mode. The result is your discount amount. For a $149 item: 20% of $149 = $29.80 savings → sale price = $149 − $29.80 = $119.20. For stacked discounts (20% off, then an extra 10%), calculate sequentially — not by adding the percentages — because the second discount applies to $119.20, not the original $149.
Percentage points are the arithmetic difference between two percentages. If a tax rate rises from 20% to 25%, it has increased by 5 percentage points. Percentage change is the relative change: ((25 − 20) ÷ 20) × 100 = 25% increase. These describe the same move very differently. Percentage change is usually a larger, more dramatic number, while percentage points describe the literal numeric gap.
Multiply the decimal by 100 and add the % symbol. Examples: 0.75 → 75%, 0.08 → 8%, 1.25 → 125%. To convert back from a percentage to a decimal, divide by 100: 75% → 0.75. Decimals above 1.0 represent percentages above 100%, which occur when comparing a value that is larger than the baseline (e.g., 200% means twice as large).
Use the standard formula with the base year as Original Value. Example: revenue of $500,000 in 2023 and $620,000 in 2024 → ((620,000 − 500,000) ÷ 500,000) × 100 = 24% growth. For multi-year compound growth, you would need a CAGR (Compound Annual Growth Rate) calculation, but for single-year changes the "% Increase/Decrease" mode in this calculator gives the correct result directly.
Percentage error = (|Estimated Value − Actual Value| ÷ Actual Value) × 100. It measures how far your measurement or estimate is from the true value. Example: estimating 52 cm when the actual is 50 cm → (|52 − 50| ÷ 50) × 100 = 4% error. You can use the "% Increase/Decrease" mode — enter actual as Original and estimated as New — then take the absolute value of the result.
Yes. Use the "What is X% of Y?" mode with the tax rate as X and the pre-tax price as Y. For a $200 purchase in New York City (total sales tax 8.875%): 8.875% of $200 = $17.75 in tax, making the total $217.75. Note that sales tax rates vary by state and locality — California base rate is 7.25% (with some counties up to 10.5%), while Oregon and Montana have no sales tax at all.
Yes. This LiteCalc percentage calculator is completely free, requires no account or sign-up, and works on any device with a modern web browser. It handles three calculation modes — basic percentage, percentage ratio, and percentage increase or decrease — all with instant results and a copy-to-clipboard feature.