Exact inch to millimeter reference

7/8 inch to mm: 22.2250 mm

Convert 7/8 inch to millimeters for CNC setup sheets, drawings, inspection notes, and supplier communication. The formula uses the exact international inch standard.

Answer first

7/8 inch =

22.2250 mm

2 decimals: 22.23
3 decimals: 22.225
4 decimals: 22.2250

Formula and precision policy

mm = inch × 25.4 → 0.875 × 25.4 = 22.2250 mm

The exact conversion uses 1 inch = 25.4 mm. This page displays 22.2250 mm by default. For CNC, inspection, RFQ, or supplier documents, keep the precision required by the drawing, tolerance block, process plan, or inspection equipment.

Equivalent forms

7/8 inch = 0.875 inch
0.875 inch × 25.4 = 22.2250 mm
22.23 mm rounded to 2 decimals; 22.225 mm rounded to 3 decimals

Nearby inch to mm values

Value	Decimal inch	Millimeters	Reference
3/4 inch	0.75	19.0500 mm	Open page
5/8 inch	0.625	15.8750 mm	Open page
1/2 inch	0.5	12.7000 mm	Open page
1-1/4 inches	1.25	31.7500 mm	Open page
7/16 inch	0.4375	11.1125 mm	Open page
3/8 inch	0.375	9.5250 mm	Open page

Manufacturing context and caveat

A 7/8 inch dimension may affect tooling, clearance, or stock planning. Confirm the required tolerance and measurement method separately.

Reference-only caveat: this conversion does not certify tolerance, fit, pressure, load, code compliance, material equivalence, or interchangeability. Confirm the controlling drawing, standard, supplier data, and engineering approval before manufacturing.

FAQs

How many millimeters is 7/8 inch?

7/8 inch equals 22.2250 mm using the exact conversion factor 1 inch = 25.4 mm.

What formula converts 7/8 inch to mm?

Use mm = inch × 25.4. For this page, 0.875 × 25.4 = 22.2250 mm.

Should I round 22.2250 mm for CNC or inspection work?

Use the precision required by the drawing, process plan, or inspection method. This page shows 22.23 mm, 22.225 mm, and 22.2250 mm so you can choose the appropriate display precision.

Is 7/8 inch the same as 0.875 inch?

Yes. 7/8 inch is represented here as 0.875 inch before multiplying by 25.4 to get millimeters.

Can this conversion decide fit, tolerance, or replacement parts?

No. This is a reference unit conversion only. Confirm drawing tolerances, standards, material specifications, supplier certificates, and engineering approval before manufacturing or substituting parts.