number drill · nominal diameter

#25
drill bit size.

A #25 bit measures 0.1495 in across (3.797 mm).

The inch decimal is the published nominal designation; millimetres are a conversion.

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

#25 · number

0.1495 in

3.797 mm

Designation#25number

Inch decimal0.1495nominal

Metric conversion3.797millimetres

Where this size sits from 0 to 1 inch

#25 · 3.797 mm on a zero to 25.4 millimetre scale. Neighbor marks: 3.8 mm, #26.

0 25.4 mm

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Measured neighbors

What sits beside #25.

“Nearest” means nominal diameter only. It does not make a neighboring size acceptable for a tolerance, tapping, reaming, or fastener application.

Other naming systemsABSOLUTE DIAMETER DELTA

3.8 mmmetric 0.1496 inΔ +0.003 mm 3.7 mmmetric 0.1457 inΔ -0.097 mm 3.9 mmmetric 0.1535 inΔ +0.103 mm 5/32fractional 0.1563 inΔ +0.171 mm

Same seriesNEAREST NOMINAL ROWS

#26number 3.734 mmΔ -0.063 mm #24number 3.861 mmΔ +0.064 mm

Source record

ASME.

The standard text is paywalled. Number and letter series are cross-checked against public manufacturer charts; exact standard edition/page verification remains a release gate.

Open source record

#25drill bit size.

What sits beside #25.

ASME.

#25
drill bit size.