number drill · nominal diameter

#15
drill bit size.

A #15 bit measures 0.1800 in across (4.572 mm).

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

Diameter conversion cross-checked

Calibrated relative diameter · 1 in reference

#15 · number

0.1800 in

4.572 mm

Designation#15number

Inch decimal0.1800nominal

Metric conversion4.572millimetres

Where this size sits from 0 to 1 inch

#15 · 4.572 mm on a zero to 25.4 millimetre scale. Neighbor marks: 4.6 mm, #14.

0 25.4 mm

Show calibrated outline Open in Finder

Measured neighbors

What sits beside #15.

“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

4.6 mmmetric 0.1811 inΔ +0.028 mm 4.5 mmmetric 0.1772 inΔ -0.072 mm 4.7 mmmetric 0.1850 inΔ +0.128 mm 4.4 mmmetric 0.1732 inΔ -0.172 mm

Same seriesNEAREST NOMINAL ROWS

#14number 4.623 mmΔ +0.051 mm #16number 4.496 mmΔ -0.076 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

#15drill bit size.

What sits beside #15.

ASME.

#15
drill bit size.