How to Calculate Percentage Increase: A Step-by-Step Guide
Adds a percentage to a number.
These calculations come up in school, at work and in daily life, from PSLE and O-Level practice to measuring a room for new flooring. Doing them by hand builds understanding, and a calculator lets you check the answer instantly.
What you need
- Starting value
- Increase (%)
Step by step
- Enter the starting value.
- Enter the increase (%).
- The results update as you type, or press Calculate.
- Read the new value first, then the supporting figures below it.
The formula
New = value × (1 + p/100).
Worked example
For example, with these inputs:
- Starting value: 250
- Increase (%): 12
the calculator returns:
- New value: 280
- Increase: 30
A second example
Now change the inputs to:
- Starting value: 312
- Increase (%): 12
the calculator returns:
- New value: 349.44
- Increase: 37.44
Practical tips
- Round only at the final step to avoid accumulated rounding errors.
- For exam work, show your method; marks are often given for working, not just the answer.
- Write down the formula before plugging numbers in; it prevents mixing up variables.
- Check your answer by working backwards from the result.
Background
A quick mental estimate before calculating is a powerful check. If a room's floor area comes out at 4,000 square metres or a percentage comes out above 100% when it should not, you know to look again.
These calculations appear throughout the Singapore syllabus, from primary school percentages and fractions to secondary school algebra and geometry. Understanding the formula makes problem sums easier because you can recognise which quantity is missing.
Rounding is a common source of small errors. Keep full precision during intermediate steps and round only the final answer to the number of decimal places or significant figures the question asks for.
Related calculations
- Volume of a Square Pyramid Calculator: Calculates the volume of a square pyramid from the measurements you enter.
- Volume of a Hemisphere Calculator: Calculates the volume of a hemisphere from the measurements you enter.
- Surface Area of a Cube Calculator: Calculates the surface area of a cube from the measurements you enter.
- Surface Area of a Cuboid Calculator: Calculates the surface area of a cuboid from the measurements you enter.
Want to skip the arithmetic? The free Percentage Increase Calculator does all of this instantly and updates as you type.
Run your own numbers: Percentage Increase Calculator