Decimal
0.2 × 15 = 3
Fraction
⅕ of 15 = 3
Equation
(20 ÷ 100) × 15 = 3
How to calculate 20% of 15
Two steps — convert to a decimal, then multiply.
- 1
Convert the percentage to a decimal
20 ÷ 100 = 0.2
- 2
Multiply the original number by the decimal
0.2 × 15 = 3
Where 20% of 15 comes up in practice
A 20% tip on a $15 restaurant bill comes out to $3.00, bringing the total to $18.00.
How to read this number
- 20% is the modern US standard tip for good service — $3.00 on a $15.00 bill brings the total to $18.00.
Mental math shortcut
⅕ — divide by 5. Or take 10% and double it.
The same calculation, expressed three ways
Knowing one of these gives you the other two — handy when a problem is phrased differently to what you typed.
- 3 is 20% of 15
- 3 out of 15 = 20%
- 20% off $15.00 = $12.00
Frequently asked
Common follow-up questions for 20% of 15.
Yes — multiplying by the decimal form (0.2) is exactly what "20% of 15" means. 15 × 0.2 = 3.
20% equals ⅕. So ⅕ of 15 = 3, which is the same answer reached the long way.
⅕ — divide by 5. Or take 10% and double it. For 20% of 15 that gives 3 directly.
The number is 15. To work it out, divide 3 by 0.2: 3 ÷ 0.2 = 15.
Total = $18.00. The bill ($15) plus a 20% tip ($3.00) = $18.00.
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Use the full Percentage Calculator — five modes including reverse calculations, percentage change, and percentage difference.
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