What is 20% of 30?
The answer is 6.
Result Explanation
20% of 30 = 6. Because 20% is one fifth, you can also do 30 ÷ 5 = 6. If you mean 20% off 30, then 6 is the discount and the new total is 24 (use the discount calculator for before/after).
If you’re comparing two values (not taking a slice of one number), use the percentage change calculator. For reverse problems like “30 is 20% of what?”, use the reverse percentage calculator.
Why Six Lines Up with Three Tens
Taking a fifth of thirty removes the factor of five from thirty’s 2 × 3 × 5 skeleton and leaves 2 × 3 = 6. That is the same product you get from doubling 10% of 30 (3), which shows two independent mental routes converging on one till-friendly integer.
Compared with 20% of 20 (4), adding ten to the base adds two pounds to the fifth—linear scaling again. If someone moves a quote from twenty to thirty pounds at the same twenty-percent rate, the fee or discount chunk grows by exactly two.
Mental Maths Shortcuts for 20% of 30
Fastest: 30 ÷ 5 = 6.
- 10% of 30 = 3; double → 20% = 6.
- Three tens: 20% of 10 = 2 each → 2 + 2 + 2 = 6.
From 25% of 30 = 7.5, subtract 5% of 30 = 1.5 to return to 6—useful if your head anchors on quarters first.
Real-World Examples
Example 1: Twenty percent off a £30 shirt
The markdown is £6 and you pay £24 if nothing else is stacked on the ticket.
Example 2: Class trip kitty
If thirty pupils each put in a pound and the organiser sets aside 20% of the £30 float for first aid snacks, that reserve is £6, leaving £24 for transport lines if the rule is strict.
Example 3: Streaming add-on
A bolt-on quoted as 20% of a £30 bundle component costs £6; the remainder of that component’s headline would be £24 only if the wording describes a discount, not a surcharge on top.
Example 4: Order-of-magnitude check
Ten times the base moves you to 20% of 300 (60). If your spreadsheet shows 600 or 0.6 instead, you have likely misplaced the decimal tied to the percent conversion.
Common Mistakes
- Quoting £24 when the exam line asked only for twenty percent of £30—twenty-four is the post-discount amount, not the discount.
- Multiplying 20 × 30 without dividing by a hundred, then staring at 600.
- Dividing 30 by 20 and treating 1.5 as if it were a percentage answer—wrong operation entirely.
- Confusing 20% of 30 with “30 is 20% of what?”—that reversed setup needs 30 ÷ 0.2 = 150.
- Reading 0.2% of thirty as twenty percent, which shrinks the true slice toward zero.
Related Links
FAQ
What is 20% of 30?
20% of 30 is 6.
How do you calculate 20% of 30?
Multiply 30 by 0.2, or divide 30 by 5 because 20% is one fifth.
What is 20% off 30?
20% off 30 is a reduction of 6, leaving 24.