📏 Inch Fraction Calculator — Decimal, Fraction & MM Conversion

0.375 inches is exactly 3/8 of an inch — the 6th mark on a tape measure's 1/16 scale. In millimeters it is 9.525 mm. This is one of the most common decimals in woodworking because a standard saw kerf is 1/8 inch and three kerf-widths of layout land on 0.375.

0.625 inches is exactly 5/8 of an inch — the 10th mark on a 1/16 tape scale, or 15.875 mm. Quick trick: the digits past the decimal map to eighths — .625 is 5/8, .375 is 3/8, .875 is 7/8 — because each 0.125 step is one eighth.

0.875 inches is exactly 7/8 of an inch — the 14th mark on a tape measure, 22.225 mm. It reads as 'seven eighths' everywhere in the shop: 7/8" spindle, 7/8" chisel, 7/8" drill bit are all 0.875 in decimal drawings.

0.1875 inches is exactly 3/16 of an inch — the 3rd mark on a 1/16 tape scale, or 4.763 mm. It is half of 3/8, which makes it a common half-step in plywood edge details and reveal gaps.

0.3125 inches is exactly 5/16 of an inch — 7.938 mm. On a 1/16 tape it sits between the 5th mark (5/16 = 0.3125 exactly on the 1/32 scale) and reads as five-sixteenths: halfway between 1/4 and 3/8.

0.6875 inches is exactly 11/16 of an inch — 17.463 mm. If you searched 'what is 11 16', this is the same number: 11/16" = 0.6875" = 17.46 mm. It is one mark past 5/8 and one short of 3/4 on the tape.

0.8125 inches is exactly 13/16 of an inch — 20.638 mm. Like all the .XX25/.XX75/.XX125/.XX875 decimals, it is an odd sixteenth: 13/16 sits one mark past 3/4 on a standard tape.

0.90625 inches is exactly 29/32 of an inch — or 58/64 if your scale reads in 64ths. In millimeters that is 23.019 mm. It falls one 64th short of 59/64 and one full 32nd below 15/16, so read it as 29/32 on a machinist rule and 'just shy of 15/16' on a tape.

0.21875 inches is exactly 7/32 of an inch — 5.556 mm. This number matters to plywood buyers: it is the actual thickness of nominal 1/4" plywood, sanded. So a '1/4-inch' sheet measures 0.21875" and 7/32" bits and rebate setups match it exactly.

0.46875 inches is exactly 15/32 of an inch — 11.906 mm. It is the true thickness of nominal 1/2" sanded plywood, which is why 15/32" and 'half-inch ply' appear interchangeably on architectural specs.

Searches for '9375 in inches' almost always mean 0.9375", which is exactly 15/16 of an inch — the 15th mark on a tape, 23.813 mm. Likewise 5625 means 0.5625" = 9/16" (the 9th mark, 14.288 mm). The pattern: these are 1/64-family decimals — 0.9375 = 60/64, 0.5625 = 36/64.

On the 1/16 scale: .375 is the 6th small mark, .625 is the 10th, and .875 is the 14th. Mnemonic: the mark number is the fraction's numerator times two when the fraction is in eighths — 3/8 → mark 6, 5/8 → mark 10, 7/8 → mark 14. Values like .38 land a hair past the 6th mark, close enough that 3/8 is the reading.

0.125 inches is exactly 1/8 of an inch — the 2nd mark on a 1/16 tape, 3.175 mm. It is the standard circular-saw kerf, which is why kerf-bending layouts for plywood default to a 1/8-inch groove width.

Divide by 25.4. 1.6 mm = 0.063", which rounds to 1/16" (0.0625"); 7.5 mm = 0.295", which rounds to 19/64" (0.2969"). Neither lands exactly on a common fraction — metric sheet goods sit between imperial graduations — so pick the nearest fraction and verify with a test cut.

Multiply the decimal by 25.4. 17/64" = 0.265625" = 6.747 mm; 25/64" = 0.390625" = 9.922 mm; 0.375" = 9.525 mm exactly. For any fraction: numerator ÷ denominator × 25.4 — the converter above does it to three decimals.

3/8 is bigger. As decimals, 3/8 = 0.375 and 5/16 = 0.3125 — a difference of 1/16 inch (1.588 mm). The quick fraction trick without converting: cross-multiply 3×16 = 48 versus 5×8 = 40; since 48 > 40, 3/8 wins. The Compare tab above runs this for any pair.

Sanding. Plywood is rough-pressed slightly over nominal, then belt-sanded to a controlled thickness below nominal so panels stack predictably — 3/4" comes off the line at 23/32" (0.719", 18.3 mm), 1/2" at 15/32", 1/4" at 7/32". Un-sanded construction sheathing skips the pass and runs closer to full nominal. Design joinery to the actual number in the table above, not the label.