Quick answer
Percent increase = (new − old) ÷ old × 100. Rising from 50 to 75 is a 50% increase, a difference of 25.
Enter the original and new values. The calculator returns the percentage increase and the difference.
Related tools: Percent Decrease Calculator: Percentage decrease between two values. Percent Difference Calculator: Symmetric percent difference between two values. Percentage Change Calculator: Find the percentage increase or decrease from an old value to a new value.
How to use the Percent Increase Calculator
- Enter original value (above 0).
- Enter new value.
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Original value | A number | > 0 |
| New value | A number | — |
Formula and method
Formula
increase % = (new − old) ÷ old × 100
IEEE-754 double precision; shown to at most 6 decimal places.
The new value must be higher than the original; otherwise use the percentage change calculator.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Original value = 50; New value = 75.
| Result | Value |
|---|---|
| Percentage increase | 50 % |
| Difference | 25 |
Example 2
Inputs: Original value = 80; New value = 100.
| Result | Value |
|---|---|
| Percentage increase | 25 % |
| Difference | 20 |
The first line is the headline result (percentage increase). Below it the percent Increase Calculator lists difference, which describe the same case from other angles. IEEE-754 double precision; shown to at most 6 decimal places.
Reading the result
The increase of 25 is half of the original 50. A 100% increase doubles a value. Prices rising 50% then falling 50% do not return to the start: 75 × 0.5 = 37.5.
Where this estimate stops applying
The original must be positive and the new value above it; for drops use the Percent Decrease calculator. Percent increase can exceed 100%, for example 10 to 50 is 400%.
How the result changes with new value
Holding every other input at the first worked example, this table changes only new value. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| New value | Percentage increase | Difference |
|---|---|---|
| 75 | 50 % | 25 |
| 150 | 200 % | 100 |
| 300 | 500 % | 250 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Original value: entering "0" shows "Original value must be greater than 0." beside that field and no result.
- New value: entering "5" shows "The new value must be higher than the original." beside that field and no result.
Choosing between the Percent Increase Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Percent Decrease Calculator](/math/percent-decrease-calculator/) | original value and new value | Percentage decrease |
| [Percent Difference Calculator](/math/percent-difference-calculator/) | value 1 and value 2 | Percent difference |
| [Percentage Change Calculator](/math/percentage-change-calculator/) | old value and new value | Percentage change |
| [Reverse Percentage Calculator](/math/reverse-percentage-calculator/) | final amount, percentage applied and it was | Original amount |
| [Percent Off Calculator](/math/percent-off-calculator/) | original price and discount | Sale price |
Background: rounding and basic arithmetic
Rounding to a place looks at the digit just to its right: 0 to 4 rounds down and 5 to 9 rounds up (the half-up convention, so 2.5 becomes 3). Rounding 838.274 gives 800 to the nearest hundred, 840 to the nearest ten and 838 to the nearest one.
Some systems use banker's rounding (half to even), which sends 2.5 to 2 and 3.5 to 4; check which convention your task requires, and round only at the end of a multi-step calculation.
Assumptions and limitations
- Original must be positive
- New value must exceed original
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for original value and new value to confirm this.
Frequently asked questions
What is 20 to 30 as a percent increase?
20 to 30 is (30 − 20) ÷ 20 = 50% higher.
How do I get the new value?
Multiply by (1 + percent/100).
What if the original is zero?
It is undefined: dividing by an original of zero has no meaning, so the calculator rejects it.
What does the Percent Increase Calculator calculate?
Percentage increase between two values. It returns Percentage increase and Difference.
What formula does the Percent Increase Calculator use?
increase % = (new − old) ÷ old × 100. The new value must be higher than the original; otherwise use the percentage change calculator.
What do I need to enter in the percent Increase Calculator?
You enter Original value and New value.
How is the result rounded or limited?
IEEE-754 double precision; shown to at most 6 decimal places. Original must be positive.
What are the limits of this calculator?
Original must be positive. New value must exceed original.
What is an example of a percent Increase result?
With original value 50 and new value 75, the percentage increase is 50 %.
Related calculators
- Percent Decrease Calculator — Percentage decrease between two values.
- Percent Difference Calculator — Symmetric percent difference between two values.
- Percentage Change Calculator — Find the percentage increase or decrease from an old value to a new value.
- Reverse Percentage Calculator — Work backwards from a final amount to the original value before a percentage increase or decrease.
- Percent Off Calculator — Find the sale price and savings after a percentage discount.
- Percent Error Calculator — Compare a measured value with the true value.
- Decimal to Percent Calculator — Convert a decimal to a percentage.
- Percent to Fraction Calculator — Convert a percentage to a simplified fraction.
Sources
- OpenStax, Prealgebra 2e (Rice University): fractions, decimals, percents, ratios and rounding
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.