Convert 30 mm to inches | 30 mm ≈ 1 1/8" | Calculator

Quick Answer: 30 mm = 1.1811 inches ≈ 1 316"

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30 mm = 1.1811 inches

30 mm ≈ 1 14 in (error: 5.83%)

30 mm ≈ 1 18 in (error: 4.75%)

30 mm ≈ 1 316 in (error: 0.54%)

30 mm ≈ 1 1/8" (error: 4.75%)

Quick calculation:

  1. 30 mm ÷ 25.4 = 1.1811"
  2. 1.1811 × 8 = 9.4 → round to 9
  3. Result: 9/8

1 1/8" / 3 cm on a Ruler

Imperial (inches)

1 1/8 in on a ruler 0 1 2 3 4 1 1/8 in

Metric (cm)

3 cm on a ruler 0 1 2 3 4 5 6 7 8 9 10 3 cm

The red markers show 30 mm as 1 1/8" (imperial) and 3 cm (metric).

Learn more about converting mm to fractional inches →

Similar MM to Inches Conversions

Values close to 30 mm for quick reference:

Millimeters Decimal Inches Fractional Inches
20 mm 0.7874″ 25/32″
22 mm 0.8661″ 55/64″
24 mm 0.9449″ 15/16″
26 mm 1.0236″ 1 1/32″
28 mm 1.1024″ 1 7/64″
30 mm 1.1811″ 1 3/16″
32 mm 1.2598″ 1 17/64″
34 mm 1.3386″ 1 11/32″
36 mm 1.4173″ 1 27/64″
38 mm 1.4961″ 1 1/2″
40 mm 1.5748″ 1 37/64″

See Also

Frequently Asked Questions

How much is 30 mm in inches?

30 millimeters equals 1.1811" (exactly 30 ÷ 25.4 inches).

How do I convert 30 mm to inches?

Divide millimeters by 25.4: 30 ÷ 25.4 = 1.1811 inches.

Is the conversion exact?

Yes. 1 inch = 25.4 mm exactly (1959 International Yard and Pound Agreement). All values on this page use this exact factor.

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30 mm to inches — 1.1811"

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All unit conversions on CoolConversion use conversion factors defined or documented by internationally recognised standards bodies (such as ISO and NIST), including both SI and non-SI units.

Conversion factors verified against NIST, BIPM, ISO 80000-3 1 inch = 2.54 cm by international agreement (1959). Last reviewed: March 2026
Adilson Fernandes By Adilson Fernandes
Tiago Fernandes Reviewed by Tiago Fernandes