What is 18/21 as a Decimal?

Fraction to Decimal Converter

What is 18/21 as a decimal?

Answer

Fraction 18/21 as a decimal is

0.857142

≈ 0.86 to hundredths

Repeating decimal: 18/21 = 6/7 · denominator 7 has the factor 7, not 2 or 5 · the bar marks the period 857142 — 6 digits repeat forever

remainder	×10	= digit × 21 + new remainder	digit
18	180	8 × 21 + 12	8
12	120	5 × 21 + 15	5
15	150	7 × 21 + 3	7
3	30	1 × 21 + 9	1
9	90	4 × 21 + 6	4
6	60	2 × 21 + 18	2

Remainder 18 is back after the 6th division → the 6 digits 857142 repeat: 0.857142.

Fraction 18/21 as a decimal is 0.(857142)

To convert 18/21 to a decimal, divide the numerator by the denominator: 18 ÷ 21 = 0.(857142).

In lowest terms its denominator 7 has the prime factor 7, so the division never ends: a remainder comes back and the same digits repeat forever.

Multiply by 100: 18/21 ≈ 85.71%.