Percentage Calculator
How to calculate percentages
A percentage is just a number out of 100. The calculator above handles the three things people need most: finding a percentage of a number, working out what percentage one number is of another, and the percentage change between two numbers.
The three formulas
Worked examples
- 15% of 200 = (15/100) × 200 = 30.
- 30 is what % of 200 = (30/200) × 100 = 15%.
- Change from 200 to 250 = ((250 − 200)/200) × 100 = +25%.
Everyday uses
- Discounts: a 30% discount on ₹2,000 saves ₹600, so you pay ₹1,400.
- Marks: 420 out of 500 = 84%.
- Tips and GST: add 18% to a bill, or find a 10% service charge.
- Growth: salary rising from ₹40,000 to ₹46,000 is a 15% hike.
Percentage increase vs decrease
A common trap: a 50% rise followed by a 50% fall does not bring you back to the start. ₹100 up 50% is ₹150; down 50% is ₹75 — a net loss. That is because each percentage is taken on a different base. The calculator's "% change" mode handles this correctly for any two values.
Frequently asked questions
How do I find X% of a number?
Divide X by 100 and multiply by the number. 15% of 200 = 0.15 × 200 = 30.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. 30 of 200 = 15%.
How do I calculate percentage change?
(New − Old) / Old × 100. A positive result is an increase, negative a decrease.
How do I convert marks to a percentage?
Divide marks obtained by total marks and multiply by 100.
Does a 50% rise then 50% fall return to the start?
No — you end lower, because each percentage applies to a different base.
Source: standard percentage mathematics. ComplyKraft is independent; this is general educational information.