Percentage Calculator – Calculate Discounts, Increases, Decreases & Percentages

Percentage difficulties need not be difficult. This guide shows you how to compute a fraction of a number, figure what percentage one number is of another, calculate an original amount, calculate an increase or decrease and calculate VAT. Each part has the formula, steps and real world examples.

What does % mean?

A percentage is a number written as a fraction of 100. The word derives from the Latin per centum, which means “out of one hundred.” So 30% means 30 out of every hundred.

All the examples in this guide are just the same notion, looked at in different ways: Share (30% of 200), Percentage (30 is what percent of 200?), Base value (30 is 15% of what?), Increase/decrease, or Price + tax. Select the calculation you want to perform, enter your numbers and read off the result.

Using the calculator

1. Choose a calculation type from the menu: amount, percentage, base value, increase/decrease or VAT.
2. Enter the two values you know already.
3. Choose Calculate.
4. Read the answer, the formula and the working step by step.

Common percentage calculations

1. To find a percentage of a number

This is what most people mean when they look for “what is 20 percent of 50” or “how do I calculate a percentage of a price.” You know the total and the rate and you want the amount.

Also Searched: percentage amount calculator, what is x% of y, calculate a percentage of a number.

Some examples of:

• Restaurant tipping: 20pc on €45 bill
• Taxes and commissions: VAT on an item of €80, Commission on a transaction of €15,000, at 6%
• How much is 25% more flour than 200 g when adjusting a recipe?
• Exam marks: what is 75 percent of 80 points?
• Discounts, memberships and incentives: 30% off €90, 15% off a €40 gym membership, 10% off €65 with a loyalty card or 5% payback on a €200 purchase
• Doses and mixtures: 10 per cent of 500 ml solution

Try your own numbers by selecting “What is P% of G?” from the dropdown.

2. To Find what percent one number is of the other

This is for when you have a pair of numbers and want to know how they compare, the typical X out of Y question. People seek it as “what percentage is X of Y” or “convert a fraction to a percentage”.

Also found in: X% of Y, convert points to a percent, calculate a percentage from a ratio.

Examples:

• How to change a test grade to an actual grade: 72/90
• Spending check: €340 of €500 Budget
• Attendance or completion rate: 22 out of 30 days
• Reading survey results: 45 of 300 persons
• Election Results: 1,200 out of 5,000
• Sports victory rate: 9 victories in 12 games
• Common measurements: 43 out of 100, 3 out of 8 l, or 50 g of sugar in a 400 g mixture

3. Restoring to the original (base) value

Sometimes you know a part and its percent but not the complete. This is a reverse calculation. Maybe you searched for “X is Y percent of what number” or “find the original price before a discount.”

Also Known As: original price calculator, reverse percentage calculator, how to find the whole from a part.

Examples:

• Original price was €42 reduction was 30% off. What was the sale price?
• Total behind a deposit: 8,000 euro is 20% of the total amount, thus what is the entire amount?
• Estimating totals from a sample: 12 things is 25% stock, or 45 persons is 15% participants
• Working backward from a bill: A €6 tip was 10%. What was the bill? What was the initial price if the price after a 15% discount is €68?
• Voucher codes: you saved €25 with 20% voucher what was the original price?

4. Raising or lowering a figure by a percentage

It works both ways. Adding a percentage (surcharge, raise, price hike) or deleting one (discount, price decrease). Typical searches are: “add 15 percent to 200” and “20 percent discount calculator.”

Available also as: percent discount calculator, add percentage to a number, fee and discount calculator.

Samples:

• Additional charges and markups: 12% service fee on €60, 7% delivery cost on €50, or 15% markup on wholesale pricing
• Weight goals: lose 5% of 80 kg
• Buy one jacket get one free, 20% off a €120 jacket, 40% off in the Black Friday sale, or take an additional 10% off an already reduced price
• Regular fee increases: 8% increase in monthly fee or 6% increase in school costs

5. Percentage difference between two values

You know the initial and final figures and want the % increase or decrease. This is what you will look for: “percentage change from X to Y” or “by what percent did the price go up?”

Also try: percent change calculator, % change between 2 numbers.

Examples:

• Rent or membership increases compared to last year: rent increasing from €800 to €850
• Weight loss: 80 kg to 74 kg
• Price increases: gas from €1.50 to €1.80, anything from €50 to €65 or an electricity bill from €60 to €75
• Population or Staff increase: Increase in population from 20,000 to 21,500
• Growth numbers: followers growing from 1,000 to 1,500, or downloads growing from 500 to 800

6. VAT calculation

This is a more specialized but extremely typical computation, adding VAT to a net price to get the final amount, or subtracting VAT from a price that already contains it. It is searched as “VAT calculator net to gross” or “how much VAT is in this price”. A VAT calculator shows net, VAT and gross figures side-by-side.

Other searches: add VAT to a price, remove VAT from a price, net-gross VAT calculator.

Examples:

• Invoicing: 19% VAT on a €100 net price
• Receipts: how much VAT is there on a €238 total price?
• Freelancer and small business: Charging VAT on your service invoices
• Restaurant bills: does a bill of €45 already include VAT?
• Online orders: VAT on €60 order
• Shopping abroad: comparing net and gross pricing or quoting a net offer as a VAT inclusive price for a customer

The Three Principles

The rule of three helps you solve problems where you know three values and need to find a fourth. For example: you get €120 for 8 hours, how much do you get for 5 hours? Percentages work the same manner, but one of the variables is always fixed at 100. The calculator supports all these instances: percent of a number, what percent is a number of another, what number is a percentage of a value.

For instance:

• What is 20% of 90 €? → €18
• Tip 20% on a €45 check? ← €9
• What percent is 72 out of 90? → 80%
• 45 is what percent of 30? → 150%
• You spent €68 with a 15% discount. How much was that at first? → €80
• 19% VAT on €100 is €119. What do you get? → €119

Enter your own numbers into the calculator to get the answer and full functionality.

The seven formulas

Formula 1: What is p% of G? (find the amount)

Formula 2: What percent is Y of X? (find the percentage)

Formula 3: X is p% of what? (find the base value)

Formula 4: Increase by p%

Formula 5: Decrease by p%

Formula 6: Percentage change

Formula 7: VAT

Net to gross: Gross = Net + (Net × VAT rate ÷ 100)

Gross to net: Net = Gross ÷ (1 + VAT rate ÷ 100)

A real-life example: from discount to checkout

Here is how the formulas work together in one story. Sarah sees a jacket that used to cost €120 and is now 20% off.

• Step 1: Find the sale price (decrease formula).
  120 − (120 × 20 ÷ 100) = 120 − 24 = €96
• Step 2: Add 19% VAT (VAT formula).
  96 + (96 × 19 ÷ 100) = 96 + 18.24 = €114.24

  Sarah pays €114.24 at the till.

• Step 3: Check how much she saved (percentage formula).
  (24 ÷ 120) × 100 = 20% ✓
• Step 4: A friend asks the price without VAT (gross to net).
  114.24 ÷ 1.19 = €96 ✓, which matches Step 1.
• Step 5: Six months later the jacket costs €108. What is the change from €114.24?
  ((108 − 114.24) ÷ 114.24) × 100 ≈ −5.46%, so the price went down by about 5.5%.

Want to try a scenario like Sarah's with your own numbers? The calculator runs each of these steps for you.

Percentages work in every currency

Percentage math doesn't depend on currency. Dollars, pounds, euros or rupees, the formula is the same.

Universal formula: Result = Amount × Percentage ÷ 100

• 20% of €100 = €20
• 20% of $100 = $20
• 20% of £100 = £20
• 20% of ₹100 = ₹20

Percent, decimal and fraction conversion chart

Why talents are more important than you think %

You see percentages on price tags, payslips, bank statements and in the headlines. That’s why ‘percent calculator’ is one of the most searched resources online – people usually want a real response, not a formula.

Where we see them in everyday life:

• Shopping: “20% off” vs “30% off the second item” in any currency.
• Money: “4.5% savings interest”, “12% effective yearly rate”, or “€85 tax deducted.” You can only tell if these are good or bad by finding out what the exact amount is.
• News: Unemployment is up 2 percentage points, inflation is at 3.4%, or 45% approve. Those numbers are meaningless if you can’t tell a percent from a percentage point, or do the math yourself.
• The usual trap: 20% raise, 20% reduction, and you're not back where you started.

Common errors in percentage calculations

• Adding 20% then deleting 20% doesn't get you back to the start.
  €100 + 20% = €120. €120 − 20% = €96 not €100.
• A percent is not the same as a percentage point.
  So if an interest rate goes from 5% to 7%, that is 2 percentage points. But it is a 40% increase relative to the original 5%.
• Two discounts in a row get you less than you expect.
  If you have a 20% off and then a 10% off, the 10% is off the price after the 20% has been taken off, not the original price.
• “20% of 90” and “20% off 90” are not the same.
  20% of €90 is €18, and 20% off €90 is a new price of €72.
• VAT is not taken off by deducting a percentage.
  So 19% cannot be deducted if the price is inclusive of 19% VAT. You divide over 1.19.

Frequently asked questions

1. How can I get the original pricing before the discount?

Divide the discounted price by (1 - discount as a decimal).
Formula: Original = Sale price / (1 - discount%)
68€ paid after 15 % discount . So 68 ÷ 0.85 equals 80€ .

2. Write the formula of successive discount.

Apply the first discount, then apply the second discount on the new price, already discounted, not the original price.
Example: €100 item, 20% reduction, then another 10% off: €100 → €80 → €72. It doesn't just become €70, which is what you would get if you just added 20 and 10.

3. Can a percentage be less than zero? What does it mean?

Yes. A negative percentage indicates a reduction. −10% means 10% less. −50% meaning it 's been cut in half .

4. How do I change a percentage to a decimal or fraction?

If decimal, divide by 100 For a fraction , put the number over 100 and reduce .
75% = 0.75 = 3/4

5. How can I compute percentage growth over a number of years? (compound interest)

The formula is: Beginning value * (1 + rate) ^ number of periods.
Example: 1000 euro growth 5% for 3 years → 1.000 * 1.05 ^ 3 = ~ 1157.62 euro.

6. What is the equation for percent error?

Take the real amount and subtract the estimated value from it . Divide that by the actual value and multiply by 100 .
Formula: Percentage error = (Estimated – Actual)/Actual *100

7. What is the rule of three and what does it have to do with percentages?

It’s a way to find an unknown value when you have three related known values, by putting up a proportion. Percentages are one of these when one side is fixed at 100%.
Example: if 8 hours pay €120, then 5 hours pay is (120 ÷ 8) x 5 = €75.

Related tools and calculators

• VAT calculator – convert easily between net and gross amounts
• Percentage increase calculator – work out increases and growth
• Percentage decrease calculator – work out decreases and reductions
• Percentage difference calculator – find the percentage difference between two numbers
• Discount calculator – work out savings and the final discounted price
• Tip calculator – split the tip and the bill
• Compound interest calculator – see how wealth and returns grow
• Money math calculator – find the discount amount and the payment due date
• Decimal to percent calculator – convert decimals to percentages
• Fraction to percent converter – turn fractions into percentages
• Percent to fraction converter – turn percentages into fractions
• Fraction calculator – all kinds of fraction calculations

Last updated: 30 July 2026