Convert 1.5 Inches to MM - Accurate Calculator
Convert 1.5" to millimeters with high precision
Results at Different Precisions
🔧 DIY & Hardware
For hardware and DIY projects, 1.5" equals 38.10 mm, which is essential when working with metric tools or international specifications.
⚙️ Engineering & Manufacturing
In engineering contexts, 1.5" converts to 38.100000 mm with high precision for accurate technical specifications.
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Exact answer, measurement guidance, and nearby sizes
Direct answer and formula
1.5 inches is 38.1 mm exactly because the international inch is exactly 25.4 mm.
1 1/2 × 25.4 = 38.1 mm
Basis: 1 inch = 25.4 mm exactly (international inch definition)
Rounding, fractions, and tolerance
The converted value 38.1 mm is exact. To one decimal it is 38.1 mm; the nearest 0.5 mm is 38 mm (difference 0.1 mm), and the nearest whole millimeter is 38 mm (difference 0.1 mm). Rounded metric sizes are not interchangeable unless that difference fits the tolerance budget.
A nearby rounded size is acceptable only when its absolute difference is within the documented dimensional tolerance and all non-dimensional compatibility checks pass.
Fractional shop layout
Fractional shop layout is a useful context for 1.5 inches. The calculated counterpart is 38.1 mm. Use the exact metric value as the master reference and label any rounded field mark clearly.
- Use the exact metric value as the master reference and label any rounded field mark clearly.
- Rule graduation and pencil-line width limit practical placement.
Illustrative measurement workflow; it does not claim that this value is a standard product size.
Editorial measurement check
When dimensions form a chain, convert from the governing baseline instead of accumulating independently rounded segments.
Use the exact-derived decimal for specification work and reserve the nearby fraction or metric step for readable field notation.
Verify the final setting with the instrument or template used in the real workflow before releasing the dimension.
Nearby comparison and substitution boundary
Nearest-0.5-mm rounding maps exact results from 37.75 mm up to (but not including) 38.25 mm to 38 mm with half-up ties. Using 38 mm as a physical substitute changes this dimension by 0.1 mm; verify fit, thread, clearance, or process allowance as applicable.
Candidate: 38 mm; absolute difference: 0.1 mm.
Questions about this exact conversion
How do you convert 1.5 inches?
1.5 inches is 38.1 mm exactly because the international inch is exactly 25.4 mm.
When is a fractional or rounded value acceptable for 1.5 inches?
The converted value 38.1 mm is exact. To one decimal it is 38.1 mm; the nearest 0.5 mm is 38 mm (difference 0.1 mm), and the nearest whole millimeter is 38 mm (difference 0.1 mm). Rounded metric sizes are not interchangeable unless that difference fits the tolerance budget.
What should be checked in this fractional shop layout example?
Use the exact metric value as the master reference and label any rounded field mark clearly. Rule graduation and pencil-line width limit practical placement.
Is the closest rounded size interchangeable with 1.5 inches?
Nearest-0.5-mm rounding maps exact results from 37.75 mm up to (but not including) 38.25 mm to 38 mm with half-up ties. Using 38 mm as a physical substitute changes this dimension by 0.1 mm; verify fit, thread, clearance, or process allowance as applicable.