Percentage Tricks & Shortcuts

Master Percentages Faster 

Discover smart percentage tricks and shortcuts that make percentage calculations simple, quick, and easy to understand. 

Trick 1: Percentage ↔ Fraction Conversion

Start with the most useful conversions.

5% = 1/20            10% = 1/10         12.5% = 1/8
16⅔% = 1/6         20% = 1/5           25% = 1/4
33⅓% = 1/3         37.5% = 3/8        50% = 1/2
62.5% = 5/8         66⅔% = 2/3        75% = 3/4
80% = 4/5

Example:
37.5% of 640 = 3/8 × 640 = 240

Trick 2: Find a Percentage Quickly

Use fraction conversion for fast mental calculations.

Example: Find 12.5% of 480.

12.5% = 1/8

480 ÷ 8 = 60

Answer: 60

Trick 3: Percentage of a Percentage

Calculate one percentage of another percentage.

Example: Find 20% of 30% of 500.

30% of 500 = 150

20% of 150 = 30

Answer: 30

Trick 4: Percentage Increase or Decrease

Understand the basic percentage change.

Example: A price increases from ₹200 to ₹250.

Increase = 250 − 200 = 50

Percentage increase = 50/200 × 100 = 25%

Answer: 25% increase

Trick 5: Successive Percentage Change

For successive changes:

Net change = a + b + ab/100

Use a negative sign for a decrease.

Example: Increase by 20%, then decrease by 10%.

20 − 10 − 2 = 8% increase

Answer: 8% increase

Trick 6: Reverse Percentage

Find the original value when the final value is known.

Example: A number is increased by 25% and becomes 500.

Original = 500 × 100/125
= 400

Answer: 400

Trick 7: Percentage Comparison

Remember that "more than" and "less than" use different bases.

Example: A is 25% more than B.

Take B = 100.

A = 125.

B is less than A by:

25/125 × 100 = 20%

Answer: B is 20% less than A

Trick 8: Expenditure–Consumption

Keep expenditure constant when price changes.

Example: Price increases by 20%. What percentage should consumption decrease?

Required decrease:

20/120 × 100 = 16⅔%

Answer: 16⅔% decrease

Trick 9: Population Growth

Apply successive percentage growth.

Example: Population increases by 10% every year. Find the increase after 2 years.

10 + 10 + (10 × 10)/100
= 20 + 1
= 21%

Answer: 21% increase

Trick 10: Marks & Percentage

Use percentage differences to quickly find total marks.

Example: One student gets 40% and fails by 20 marks. Another gets 50% and passes by 30 marks.

Difference in percentage = 10%

Difference in marks = 20 + 30 = 50

10% = 50

100% = 500

Answer: Maximum marks = 500

Trick 11: Equal Percentage Increase and Decrease

An equal increase and decrease don't cancel.

Example: A price increases by 20% and then decreases by 20%.

Take original = 100.

100 → 120 → 96

Loss = 4

Answer: 4% decrease

Trick 12: Percentage Change in Profit/Loss

Connect percentage changes with profit and loss.

Example: An article costing ₹500 is sold for ₹600.

Profit = 600 − 500 = 100

Profit% = 100/500 × 100 = 20%

Answer: 20% profit