Convert 1 1/2 Inches to MM - Accurate Calculator
Convert 1 1/2" to millimeters with high precision
Results at Different Precisions
🔧 DIY & Hardware
For hardware and DIY projects, 1 1/2" equals 38.10 mm, which is essential when working with metric tools or international specifications.
⚙️ Engineering & Manufacturing
In engineering contexts, 1 1/2" 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 1/2 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.
Model envelope check
Use 1 1/2 inches in this model envelope check workflow: an inch-dimensioned model envelope must be checked against a metric build or work area. Here the metric/imperial counterpart is 38.1 mm. Convert every axis and retain margin for placement, supports, or clamps.
- Convert every axis and retain margin for placement, supports, or clamps.
- A mathematical fit at zero margin is not a practical fit.
Illustrative measurement workflow; it does not claim that this value is a standard product size.
Editorial measurement check
Treat the source dimension as a controlled observation; preserve whether it represents a minimum, maximum, target, or nominal label.
A nearby catalog or tool size is only a candidate for review; numerical proximity does not establish interchangeability.
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
What is 1 1/2 inches in the other unit?
1 1/2 inches is 38.1 mm exactly because the international inch is exactly 25.4 mm.
Is the displayed result for 1 1/2 inches exact or rounded?
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 can conversion alone not decide in this example?
Convert every axis and retain margin for placement, supports, or clamps. A mathematical fit at zero margin is not a practical fit.
What is the nearby-size boundary for 1 1/2 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.