Enter a starting value and a percentage to instantly calculate the new value after the increase and the exact amount added.
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The formula has two parts. First, find the increase amount by multiplying the original value by the percentage divided by 100. Then add it to the original.
Increase amount = Original value × (Percentage ÷ 100)
New value = Original value + Increase amount
Or equivalently: New value = Original value × (1 + Percentage ÷ 100)
For example, increasing 500 by 20% means multiplying 500 by 0.20 to get 100, then adding that to 500 for a result of 600. The multiplier shortcut is 500 × 1.20 = 600.
Adding a percentage to a number comes up in surprisingly many contexts. Salary negotiations often involve a proposed raise like "5% increase on your current base." Retail pricing uses it when applying a markup or adding sales tax. Investment growth projections require repeated percentage additions — if your portfolio returned 8% this year, you need to add 8% to last year's value to find the new balance.
In business, price increases are typically communicated as percentages. Knowing the actual dollar amount behind "a 12% supplier price hike" tells you the real cost impact. This calculator does that conversion instantly.
"Percentage increase" adds a known percentage to a starting number (e.g., "add 15% to 200"). "Percentage change" compares two values and finds the percentage between them (e.g., "200 to 230 is a 15% change"). They use the same underlying math but answer different questions.
This calculator handles the first case: you know the original value and the percentage, and you want the result. If you already have two values and need to find the percentage between them, you want a percentage change calculator instead.
For a 10% increase, move the decimal point one place left and add that to the original. For 5%, halve the 10% result. For 1%, move the decimal two places left. These building blocks let you estimate most common percentages in your head.
Example: 15% of 800. 10% is 80, 5% is 40, so 15% is 120. The new value is 920. For exact figures or less round numbers, the calculator above saves you the arithmetic.
Multiply 500 by 20/100 (which is 0.20) to get the increase amount: 100. Add that to 500 and you get 600. The shortcut: 500 × 1.20 = 600.
Yes. A 20% increase on −500 gives −500 + (−500 × 0.20) = −500 + (−100) = −600. The value moves further from zero in the negative direction, which is mathematically correct: the magnitude increases by 20%.
A 200% increase on 50 means 50 × 2.00 = 100 added to the original, giving 150. The new value is three times the original (the original plus twice the original). Any percentage above 100% means the increase alone exceeds the starting value.
No. If you increase 100 by 25% you get 125. Decreasing 125 by 25% gives 93.75, not 100. This happens because the 25% decrease is calculated on the larger number (125), so it removes more than was added. The round-trip is never neutral unless the percentage is 0%.
To add a percentage in Excel, put the original value in A1 and the percentage in B1 (as a whole number like 20). In C1, enter: =A1*(1+B1/100). This gives the new value. For the increase amount alone, use =A1*B1/100.
This calculator is for general informational purposes. Verify critical financial, tax, or business calculations independently. Results are computed client-side — no data is sent or stored.