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Percentage Increase Calculator

Find how far a value rose or fell in percent — price hikes, salary raises, discounts and investment returns. Enter the old and new numbers; the calculator shows the change and the formula.

How percentage increase works

The formula is simple: subtract the old value from the new value, divide by the old value, and multiply by 100. A price that moves from $50 to $65 is (65 − 50) ÷ 50 × 100 = a 30% increase. Use the percentage calculator above in "Percent change" mode — it shows the formula with your numbers, so the result is always verifiable. A negative answer means a decrease: $80 down to $60 is −25%.

Discounts are just negative increases

A "25% off" sale is a −25% change. Enter the original price and the sale price to confirm the discount is what the sign claims — retailers occasionally round in their favor. The same mode checks markups: buy at $40, sell at $55, and you have added a 37.5% margin.

Common uses: pay rises, rent and returns

Percentage increase is the language of money over time. A $3,000 salary rising to $3,240 is an 8% raise. Rent going from $1,200 to $1,320 is a 10% increase — worth knowing before you sign. An investment growing from $1,000 to $1,150 returned 15%. Landlords, employers and investors all quote changes this way, so reading the numbers correctly protects your wallet. Because the calculator accepts decimals, figures like $1,299.99 work without rounding first.

Watch the starting point

Percent change needs a starting value greater than zero — dividing by zero is undefined, so the tool will ask you to enter one. Also note that increases and decreases do not cancel symmetrically: up 50% then down 50% does not return you to the start ($100 → $150 → $75). For plain "what percent is X of Y" questions, use the percent calculator instead.

Private by design

Pay figures and prices stay on your device. All calculation happens locally in your browser; nothing is uploaded or tracked.

Frequently asked questions

How do you calculate percentage increase?

Subtract the old value from the new value, divide by the old value, and multiply by 100. From $50 to $65: (65 − 50) ÷ 50 × 100 = a 30% increase.

How do I work out a discount as a percent?

Use the same percent-change mode: enter the original price and the sale price. A drop from $80 to $60 shows as −25%, i.e. 25% off — handy for checking sale signs.

What does a negative result mean?

A decrease. The sign tells the direction: positive is an increase, negative is a decrease. Going from 200 to 150 is a −25% change.

Why can't the starting value be zero?

Percent change divides by the starting value, and division by zero is undefined. Enter a starting value greater than zero.

Is my data uploaded anywhere?

No. The calculation runs entirely in your browser — prices and salaries stay on your device.

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