15% of 240 is 36. The calculator handles other everyday questions too: what percent one number is of another, how much a value changed in percent, and what a price becomes after adding or removing a percentage. Choose a mode above and enter two numbers.
Percent of a number
Multiply the number by the percentage divided by 100. For 15% of 240, that means 240 times 0.15, which gives 36. It suits tips, discounts and shares of a total.
What percent one number is of another
Divide the first number by the second, then multiply by 100. A score of 36 out of 240 is 15%. Budgets and group shares work the same way. Enter the part as X and the whole as Y.
Percentage change
Subtract the old value from the new one, divide by the old value and multiply by 100. Going from 80 to 100 is a rise of 25%. Going from 100 back to 80 is a drop of 20%. The two directions differ, which catches many people off guard.
Adding a percentage
Multiply the amount by one plus the percentage. Adding 13% HST to $100 means multiplying by 1.13, which gives $113. Sales tax, markups and raises all work like this. The mode “Add X% to Y” does it for you.
Subtracting a percentage
Multiply by one minus the percentage instead. A 30% discount on $120 leaves 70% of the price, or $84. That beats working out the discount and then subtracting it. The “Subtract” mode checks a sale price quickly.
Common mistakes
Raise a price by 20%, then cut it by 20%, and you end up 4% lower than you began. Percentage points cause trouble as well. A rate moving from 4% to 5% is one point, yet it is a 25% increase.
Tips and shares
For a 15% tip on a $64 restaurant bill, take 10% and add half of it to get $9.60. Splitting a bill means dividing the total by the number of people. A share of a budget needs the second mode, with the part and the whole. Small checks like these save time every day.
Finding the price before tax
A receipt shows $113 after 13% HST. Taking 13% off that total gives $98.31, which is wrong. The tax was added to the smaller amount, so divide by 1.13 instead and you get $100. Any time a percentage was added, divide to undo it. This is a frequent slip when checking receipts.
Rounding
Rounded percentages often add up to 99% or 101%, and that is normal. With money, round to the nearest cent at the end rather than at each step. The calculator keeps full precision throughout and rounds only what it displays.
Percentages in daily life in Toronto
Toronto shoppers meet 13% HST on most purchases, tips of 15% to 20% and rent that can rise by a set percentage each year. Comfort with percentages lets you check a bill, weigh a raise against rising prices and see what a rent increase really costs.
Where to go next
The discount calculator works out a sale price and its tax. Add sales tax with the GST and HST calculator, or look at a raise in the salary increase calculator.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage divided by 100.
How do I find percentage change?
Subtract the old value from the new one, divide by the old value and multiply by 100.
How do I add a percentage to a price?
Multiply the price by one plus the percentage as a decimal.
What is 15% of 240?
36.
Why is a 20% rise then a 20% fall not zero?
Because the fall applies to the larger amount. You end 4% lower.
What is the difference between percent and percentage points?
Points measure the gap between rates. Percent measures relative change.
Sources and updates
Last reviewed: . Full disclaimer. How we build calculators. Editorial policy.
Estimate only. This calculator gives general information for planning. It is not tax, legal or financial advice, and it is not affiliated with the City of Toronto, MPAC or the Canada Revenue Agency. Results depend on the numbers you enter and may differ from official amounts. Check official sources or a qualified professional before you decide.