Percentage Calculator
Calculate percentages, percentage difference and percentage change instantly. Work out what 20% of any number is, find discounts, markups and more.
Result
100
How it works
result = (percent ÷ 100) × number. Mode 2: (value ÷ total) × 100. Mode 3: ((to − from) ÷ from) × 100.
Example: 20% of 500 = 100. Or 240 vs 200 = +20%.
Last updated: September 2026
How this calculator is verified
Checked by Rahim Virani on
- Percentage of a number verified against 20% of 500 = 100
- Percentage difference is order-independent; percentage change is not — tested with reversed inputs
- Negative and zero base cases return an explicit error rather than Infinity or NaN
The full verification method is on our how we verify page. Found an error? Tell us and we will re-check it.
When to Use This Calculator
A shopkeeper in Pune needs to add 18% GST to a ₹1,500 repair bill. Enter 1500 as the base value and 18 as the rate, and select the option labelled percentage of a number. The calculator shows 270 as the GST amount, so the total the customer pays is ₹1,770. The same inputs work for discounts: 10% of ₹1,500 is ₹150, which makes the discounted price ₹1,350. For a different task, enter two amounts to get the percentage difference or the percentage change between them.
How to Use This Calculator
- Step 1: Enter the base value in the first field, such as a bill amount or an MRP.
- Step 2: Type the percentage rate, for example 18 for GST or 10 for a discount.
- Step 3: Choose the operation you need: percentage of a number, percentage difference between two values, or percentage change over time.
- Step 4: Read the computed amount in the result panel, along with the total or the difference where applicable.
Worked Example
A shopkeeper in Pune needs to add 18% GST to a ₹1,500 repair bill. Enter 1500 as the base value and 18 as the rate, and select the option labelled percentage of a number. The calculator shows 270 as the GST amount, so the total the customer pays is ₹1,770. The same inputs work for discounts: 10% of ₹1,500 is ₹150, which makes the discounted price ₹1,350. For a different task, enter two amounts to get the percentage difference or the percentage change between them.
Tips and Common Mistakes
- •Tip 1: Check which amount the percentage applies to, since a discount is taken from the MRP while GST is added on top of the base price.
- •Tip 2: For percentage difference the order of the two values does not matter, but for percentage change it does, because change is measured from the starting value.
- •Tip 3: To recover the pre-tax price from a GST-inclusive bill, divide the billed amount by 1.18 for 18% GST.
- ✗Mistake 1: Entering the rate as a decimal like 0.18 when the calculator expects a whole number like 18.
- ✗Mistake 2: Confusing percentage difference with percentage change, since they use different formulas and give different answers.
Expert Note
Percentage is one of the most tested topics in CBSE Class 10 board exams. The three operations — finding percentage of a number, percentage difference, and percentage change — cover nearly all school-level percentage problems. For GST calculations, always use the whole number rate (18 for 18%), not the decimal form.
Sources and References
- •NCERT Class 8 Mathematics, Chapter 8: Comparing Quantities
- •CBSE Handbook on Percentage and Fractions
Official sources are linked so you can confirm the current rate yourself. Check the linked page for the latest notification before relying on these figures.
Frequently Asked Questions
How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100. For example, 20% of 500 is 500 × (20 / 100) = 100.
How do I calculate what percent one number is of another?
Divide the first number by the second number and multiply by 100. If 150 is part of 500, then (150 / 500) × 100 = 30%.
How do I calculate percentage increase or decrease?
Subtract the original value from the new value, divide by the original value, and multiply by 100. A positive result is an increase and a negative result is a decrease.
Is a percentage calculator free to use?
Yes, True Calculator's percentage calculator is completely free with no sign-up, no app install and no usage limits.
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