Convert 1/2 Inches to MM - Accurate Calculator
Convert 1/2" to millimeters with high precision
Results at Different Precisions
1/2 inch = 12.7 mm exactly.
Exact result
Exact conversion: 1/2 × 25.4 = 12.7 mm.
Approximation
Common approximation: people may say about 13 mm in casual notes, but 12.7 mm is the exact value.
Fit caveat
Pipe, fittings, and lumber can use nominal sizes. A 1/2 inch label does not always mean the measured part is exactly 12.7 mm.
Pipe, fittings, and hardware
1/2 inch appears often in fittings, fasteners, and hardware references. Confirm whether the label is nominal or measured before matching metric parts.
Tape measure midpoint and woodworking
Half-inch marks are common layout references. Use 12.7 mm when translating a measured half-inch spacing into metric notes.
Nearby fractions give context: 3/8 inch is 9.525 mm, 5/8 inch is 15.875 mm, and 1/4 inch is 6.35 mm.
🔧 DIY & Hardware
For hardware and DIY projects, 1/2" equals 12.70 mm, which is essential when working with metric tools or international specifications.
⚙️ Engineering & Manufacturing
In engineering contexts, 1/2" converts to 12.700000 mm with high precision for accurate technical specifications.
Frequently Asked Questions
How many mm is 1/2 inch?
1/2 inch is 12.7 mm exactly.
Is 1/2 inch the same as 13 mm?
No. 1/2 inch is 12.7 mm. 13 mm is a rough nearby size and is 0.3 mm larger.
Why can 1/2 inch pipe be different from 12.7 mm?
Pipe and fitting labels are often nominal trade sizes, so the measured outside or inside diameter may not equal 12.7 mm.
What is 1/2 inch used for?
It is common in fittings, hardware, woodworking layout, and tape measure midpoint references.
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