3/8 as a Decimal

3/8 as a decimal is 0.375. Divide the numerator by the denominator - 3 ÷ 8 - and that's the answer. What's more useful than the answer alone is knowing why it comes out so clean, because that same reasoning tells you instantly whether any other fraction will terminate or repeat.

How to Convert 3/8 to a Decimal, Step by Step

Converting a fraction to a decimal always comes down to one operation: divide the top number (numerator) by the bottom number (denominator). For 3/8, that's 3 ÷ 8, using long division:

1. 3 doesn't divide evenly by 8, so start with “0.” and bring down a zero: 30 ÷ 8 = 3, remainder 6.
2. Bring down another zero: 60 ÷ 8 = 7, remainder 4.
3. Bring down another zero: 40 ÷ 8 = 5, remainder 0 - the division ends here.
4. Reading the digits back: 0.375.

You can check the answer in reverse: 0.375 × 8 = 3, which confirms 3/8 = 0.375.

A Faster Way: Skip Division Entirely

Long division isn't the only route. Since 8 fits evenly into 1000 (8 × 125 = 1000), you can multiply both the numerator and denominator by 125 instead: 3/8 becomes 375/1000, and 375/1000 is just 0.375 written out. No division required - only fractions with a denominator that divides evenly into 10, 100, 1000, or another power of 10 can use this shortcut, which is exactly what makes the next section worth understanding.

Is 3/8 a Terminating or Repeating Decimal?

3/8 is a terminating decimal - it ends cleanly rather than going on forever. Not every fraction is so tidy: 1/3, for example, becomes 0.3333… with no end. The rule that decides which one you get is the denominator's prime factors. If a fraction in its lowest terms has a denominator made up of only 2s and/or 5s, it terminates, because that denominator can always be scaled up into a power of 10 (exactly what the shortcut above does). 8 is 2 × 2 × 2 (2³), so 3/8 always lands on a clean, three-digit decimal. A denominator like 3, 6, or 7 carries other prime factors, which is why those produce repeating decimals instead. For a deeper walkthrough of both conversion methods, Math Is Fun's guide to converting fractions to decimals is a solid reference.

3/8 as a Percentage

Once you have the decimal, the percentage is one more step: multiply by 100. 0.375 × 100 = 37.5%, so 3/8 and 37.5% describe the same amount. You can verify this instantly with the Percentage Calculator's “what percent is X of Y” mode - enter 3 as the part and 8 as the whole, and it returns 37.5% directly.

Common Eighths as Decimals

Since 3/8 comes from the same family of eighths, here's the full set for quick reference:

Converting Any Fraction to a Decimal

So, 3/8 as a decimal is 0.375 - and now you know exactly why: divide numerator by denominator, and check whether the denominator's prime factors are only 2s and 5s to know if you'll land on a clean number or a repeating one. That same logic works for every fraction, not just eighths. Memorizing a few common denominators (halves, quarters, eighths, fifths, tenths) covers most everyday mental math.

For anything trickier - larger numbers, mixed numbers, or fraction arithmetic like 3/8 + 5/6 - skip the manual work and let a calculator handle the simplification and division for you.