Convert 1 inch to millimeters
"Fractional Inches to Millimeters" Calculator
How many millimeters in 1 inch?
Answer
1″ = 25.4 mm
Exact: 1″ = 25.4 mm by definition (1959), and a ruler fraction converts without rounding. If the thread is marked G 1 (BSPP), its basic outside diameter is 33.249 mm (ISO 228-1): the inch size of a pipe thread is nominal.
1 ÷ 1 = 1; 1 × 25.4 = 25.4 mm
Neighbouring sizes
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See Also
- Inches to Meters - Convert Inches to Meters
- Inches to Millimeters - Convert Inches to Millimeters
- Meters to Inches - Convert Meters to Inches
- Millimeters to Inches - Convert Millimeters to Inches
- Inches to Centimeters - Convert Inches to Centimeters
- Centimeters to Inches - Convert Centimeters to Inches
- Millimeters to Fractional Inches - Convert Millimeters to Fractional Inches
- Mm to Cm - Convert Millimeters to Centimeters
- Cm to Mm - Convert Centimeters to Millimeters
- Cm to M - Convert Centimeters to Meters
- M to Cm - Convert Meters to Centimeters
Fractional Inches to Millimeters Conversion Table
FAQ
How many millimeters in 1 inch?
1″ = 25.4 mm
What is the formula to convert 1″ to millimeters?
The formula is: mm = (numerator ÷ denominator) × 25.4. For 1″: (1 ÷ 1) × 25.4 = 25.4 mm.
What is the nearest whole millimeter to 1″?
1″ = 25.4 mm; the nearest whole millimeter is 25 mm, 0.4 mm less.