Nine calculators in one: X% of Y, X is what percent of Y, percentage change, add or subtract a percent, reverse percentage, percent difference, percentage points, ratio solver and fraction to percent, with working shown.
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<a href="https://www.toolnova.org/utilities/percentage-ratio-calculator">Percentage & Ratio Calculator</a> by ToolNova
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ToolNova. (2026, October 5). Percentage & Ratio Calculator [Online tool]. https://www.toolnova.org/utilities/percentage-ratio-calculator
MLA
“Percentage & Ratio Calculator.” ToolNova, 5 Oct. 2026, www.toolnova.org/utilities/percentage-ratio-calculator.
Solve percentages and ratios without the mental math
Pick the question you need answered and get the result with the formula worked out step by step. Find the price before tax, chain successive percentage changes, solve a:b = c:x, split a total by a ratio, scale an aspect ratio or turn 3/8 into 37.5%.
This calculator covers the everyday percentage and ratio problems people actually search for: what percent one number is of another, finding a percentage of a value, percentage increase or decrease, adding or removing a percentage, converting percentages to ratios, converting ratios to percentages, and splitting a total by percentage or ratio. Type the numbers and read the answer, with the formula shown so you can check how the result was calculated.
Successive percentage changes (e.g. +10% then −5%)
Reverse percentage to remove tax/VAT or find the original price
Ratio simplify, solve a:b = c:x, split a total and scale
Fraction ↔ decimal ↔ percent converter with common fractions
Adjustable decimal places, copy result, shareable link
How to use Percentage & Ratio Calculator
1
Choose the calculation
Tap the question that matches yours, such as % change or Reverse %.
2
Enter your numbers
Type the values. Results update as you type.
3
Read the working
The formula box shows each step so you can check it or copy it into homework.
4
Use the extras
Chain several percentage changes, see other percentages of the same number, or split a total by a ratio.
Common use cases
Working out a discount, tip, tax, or commission amount
Finding what percentage a score or part is of a total
Measuring percentage growth or decline between two figures
Adding markup or removing a discount from a price
Converting a percentage into a simplified ratio
Converting a ratio into percentage shares
Splitting a total by percentage such as a 60/40 split
Splitting a budget, bill, profit, or inheritance by ratio
Calculating three-way or multi-part percentage distributions
Checking homework or verifying a spreadsheet calculation
Detailed guide
Practical for finance, study, and everyday calculations
Use the calculator for discounts, tips, taxes, commissions, test scores, budgets, bills, recipe adjustments, financial comparisons, and other everyday calculations. It can also divide a total into percentage or ratio shares, making it useful when you need to split money or another quantity between two or more parts. Because it runs entirely client-side, it is fast and works offline once the page has loaded.
How to convert a percentage to a ratio
To convert a percentage to a ratio, write the percentage as a ratio over 100 and simplify it. For example, 40% can be written as 40:100, which simplifies to 2:5. Similarly, 25% becomes 25:100, or 1:4. When a percentage represents one part of a complete 100% split, subtract it from 100% to find the remaining share. For example, a 40% and 60% split is 40:60, which simplifies to 2:3. Use the percentage-to-ratio calculation to convert percentage values into their simplest ratio form.
How to convert a ratio to a percentage
To convert a ratio to percentages, first add all of the ratio parts to find the total number of parts. Then divide each part by the total and multiply by 100. For example, a 3:2 ratio contains 5 total parts. The first share is 3 ÷ 5 × 100 = 60%, while the second share is 2 ÷ 5 × 100 = 40%. The same method works for ratios with three or more parts, such as 3:2:1, where the total is 6 and the shares are 50%, 33.33%, and 16.67%.
How to split a total by percentage
A percentage split divides a total into separate shares. To calculate a share, multiply the total by the percentage expressed as a decimal. For example, a $10,000 amount divided into 50%, 30%, and 20% gives $5,000, $3,000, and $2,000. Percentage shares that describe the entire total normally add up to 100%. This method is useful for budgets, bills, expenses, commissions, profits, savings, and other multi-part allocations.
How to calculate a 60/40 split
A 60/40 split divides a total into two shares: 60% for one part and 40% for the other. For example, a $3,000 total split 60/40 gives $1,800 and $1,200. The same split can also be written as the ratio 60:40, which simplifies to 3:2. Enter any total and use the percentage or ratio split mode to calculate the two amounts. The method works for money, budgets, bills, commissions, profits, ownership shares, and other quantities.
Percentage change, increase, and decrease
Percentage change compares an old value with a new value. The formula is ((New Value - Old Value) ÷ Old Value) × 100. A positive result represents an increase and a negative result represents a decrease. For example, increasing from 80 to 100 is a 25% increase, while decreasing from 100 to 80 is a 20% decrease. The calculator shows the percentage change together with the absolute difference and growth factor.
Ratio versus percentage change
A ratio and a percentage change describe different relationships between numbers. A ratio compares quantities directly, while percentage change measures how much a value has increased or decreased relative to its starting value. For example, if a quantity changes from 300 to 430, the values can be compared as a ratio of 430:300, while the percentage increase is ((430 - 300) ÷ 300) × 100 = 43.33%. Use a ratio when comparing quantities and percentage change when measuring growth or decline.
Multiple percentage and three-way splits
The calculator can also be used when a total needs to be divided into three or more percentage shares. For example, a $6,000 total split 50%, 30%, and 20% produces $3,000, $1,800, and $1,200. The same approach works with more parts as long as the percentages represent the intended shares. For ratio-based distributions, enter a multi-part ratio such as 3:2:1 and the calculator determines each share of the total.
Frequently asked questions
How do I find the original price before a percentage increase?
Divide the final value by (1 + percent ÷ 100). A price of 115 including 15% tax was 115 ÷ 1.15 = 100 before tax. Use the Reverse % mode.
What is the difference between percent change and percent difference?
Percent change measures from an old value to a new one. Percent difference compares two values with no direction, dividing the gap by their average.
Why don't successive percentages add up?
Each change applies to the new value. +10% then −10% leaves you 1% lower, because the second 10% is taken from a bigger number.
How do I solve a ratio like 3:4 = 12:x?
Multiply across and divide: x = 4 × 12 ÷ 3 = 16. The Ratio mode does this and also simplifies and splits ratios.
How do I calculate what X% of a number is?
Enter the percentage and the total number. For example, 15% of 200 = 200 × 0.15 = 30. The calculator does this instantly as you type.
How do I calculate percentage increase?
Use the formula ((New Value - Old Value) ÷ Old Value) × 100. For example, if sales went from $500 to $650, the increase is ((650 - 500) ÷ 500) × 100 = 30%. The calculator shows this automatically.
How do I split a budget by ratio?
Enter your total budget and ratio, such as 60:40. The tool calculates the exact amount for each part. A $10,000 budget split 60:40 gives $6,000 and $4,000.
How do I calculate a 60/40 split?
Multiply the total by 60% for the first share and 40% for the second. For example, a $3,000 total split 60/40 gives $1,800 and $1,200. The same split can be written as the ratio 60:40, which simplifies to 3:2.
How do I calculate a discount percentage?
For an original price of $80 and a sale price of $60, the discount is ((80 - 60) ÷ 80) × 100 = 25% off. You can also enter the original price and discount percentage to find the resulting sale price.
How do I calculate tip percentage at a restaurant?
Enter your bill total and the tip percentage, such as 15%, 18%, or 20%. The calculator shows the tip amount and total to pay. Tip expectations vary by country and situation.
How do I find what percentage one number is of another?
Use the formula (Part ÷ Whole) × 100. For example, if 30 students out of 120 passed, (30 ÷ 120) × 100 = 25%. Use the 'X is what % of Y' calculator mode to solve this instantly.
How do I calculate the percentage of a number?
To find X% of a number, multiply the number by X/100. For example, 20% of 150 = 150 × 0.20 = 30. Enter the values and the calculator shows the worked result instantly.
What percent is one number of another?
Divide the part by the whole and multiply by 100. For example, 30 is 30 ÷ 150 × 100 = 20% of 150. The tool computes this directly using the percentage calculation mode.
How do I calculate percentage increase or decrease?
Percentage change = (New Value - Old Value) ÷ Old Value × 100. A rise from 80 to 100 is a 25% increase, while a drop from 100 to 80 is a 20% decrease. Enter both numbers to see the change.
How do I convert a percentage to a ratio?
Write the percentage as a ratio over 100 and simplify it. For example, 40% becomes 40:100, which simplifies to 2:5. If the percentage is one part of a complete split, use the remaining percentage to form the other side. For example, 40% and 60% gives 40:60, which simplifies to 2:3.
How do I convert a ratio to a percentage?
Add the ratio parts to get the whole, then divide each part by that total and multiply by 100. For 3:2, the total is 5, so the parts are 3 ÷ 5 × 100 = 60% and 2 ÷ 5 × 100 = 40%.
How do I convert a ratio into a percentage for three or more parts?
Add all parts of the ratio first. For example, for 3:2:1 the total is 6. The shares are 3 ÷ 6 × 100 = 50%, 2 ÷ 6 × 100 = 33.33%, and 1 ÷ 6 × 100 = 16.67%. The same method works for any number of ratio parts.
How does a reverse percentage calculator find the original number?
If a value already includes or excludes a percentage, work backwards by dividing by the appropriate multiplier. A price of $120 after a 20% increase came from 120 ÷ 1.20 = $100. A sale price of $60 after 25% off came from 60 ÷ 0.75 = $80.
What is the difference between a ratio and a percentage?
A ratio compares quantities directly, such as 3:2. A percentage expresses a share relative to 100, such as 60% and 40%. The two can describe the same relationship: 3:2 represents 60% and 40% of the total.
How do I calculate a percentage split?
Multiply the total by each percentage expressed as a decimal. For example, a $10,000 total split 50%, 30%, and 20% gives $5,000, $3,000, and $2,000. When the percentages represent the complete distribution, they should add up to 100%.
How do I calculate a 60/40 split of money?
Multiply the total amount by 0.60 for the first share and 0.40 for the second. For example, $2,000 split 60/40 gives $1,200 and $800. The 60:40 ratio can also be simplified to 3:2.
Can I split a total into three percentages?
Yes. Enter the percentages or use the ratio-split calculation for multiple parts. For example, $6,000 divided into 50%, 30%, and 20% produces $3,000, $1,800, and $1,200.
How do I calculate a ratio between two numbers?
Write the two numbers as a ratio and simplify them using their greatest common divisor when appropriate. For example, 60 and 40 form 60:40, which simplifies to 3:2. If you need the corresponding percentage shares, 3:2 represents 60% and 40%.
What is the difference between percentage change and percentage difference?
Percentage change measures movement from an original value to a new value and uses the original value as the reference. Percentage difference is generally used to compare two values without treating either one as the starting value. Use the appropriate calculation depending on whether you are measuring change or comparing two quantities.
How do I calculate a percentage increase?
Subtract the old value from the new, divide by the old value, and multiply by 100, the tool does this automatically when you enter both numbers.
How do I split an amount by ratio?
Enter the total and the ratio parts; the calculator divides the amount proportionally and shows each share.
