Circular Mil to Square Millimeter Converter

Area Converter

20 units available

Decimals:

From

To

0.000507

1 cmil = 0.000507 mm²

Formula:

mm² = cmil × 0.0005067075

With your value: 1 cmil = 0.00050671 mm²

How big is that?

Everyday references on a logarithmic scale, all expressed in circular mil so you can sanity-check the result.

Your value1.00 cmil

Postage stamp (1.2e+6× your value)1.18e+6 cmil

A4 sheet (1.2e+8× your value)1.23e+8 cmil

Parking space (2.5e+10× your value)2.47e+10 cmil

Tennis court (5.1e+11× your value)5.15e+11 cmil

Football pitch (1.4e+13× your value)1.41e+13 cmil

Other Circular Mil to Square Millimeter conversions

2 cmil to mm² 3 cmil to mm² 4 cmil to mm² 5 cmil to mm² 6 cmil to mm² 7 cmil to mm² 8 cmil to mm²

Circular Mil to Square Millimeter Conversion Table

Circular Mil (cmil)	Square Millimeter (mm²)
0.5	0.000253
1	0.000507
2	0.001013
5	0.002534
10	0.005067
15	0.007601
20	0.010134
25	0.012668
50	0.025335
100	0.050671
250	0.126677
500	0.253354
1000	0.506707

Square Millimeter to Circular Mil Conversion Table

Square Millimeter (mm²)	Circular Mil (cmil)
0.5	986.762621
1	1,973.525241
2	3,947.050483
5	9,867.626207
10	19,735.252414
15	29,602.878621
20	39,470.504828
25	49,338.131035
50	98,676.262069
100	197,352.524139
250	493,381.310347
500	986,762.620695
1000	1,973,525.24139

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Circular Mil (cmil)

Area

Exact conversion

Derived from the square metre via the length definitions above.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

Square Millimeter (mm²)

Area

Exact conversion

Derived from the square metre via the length definitions above.

Source: NIST Special Publication 811, Guide for the Use of the International System of Units

National Institute of Standards and Technology (US) · Reviewed 2026-07-01

How to Convert Circular Mil to Square Millimeter

To convert from Circular Mil (cmil) to Square Millimeter (mm²), multiply the value by 0.0005067075.

Formula: mm² = cmil × 0.0005067075

Reverse: cmil = mm² × 1,973.52524139

Step-by-Step Example

Start with your value in Circular Mil. For example: 5 cmil
Multiply by the conversion factor: 5 x 0.0005067075
The result is: 0.002534 mm²

About Circular Mil

The circular mil (cmil) is a unit of area. One circular mil equals 5.067075 × 10^-10 square metres. UnitConvertLab converts it against every other area unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: area calculations, engineering and science, education.

About Square Millimeter

The square millimeter (mm²) is a unit of area. One square millimeter equals 1.000000 × 10^-6 square metres. UnitConvertLab converts it against every other area unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: area calculations, engineering and science, education.

Frequently Asked Questions

How many Square Millimeter are in 1 Circular Mil?

There are exactly 0.0005067075 Square Millimeter in 1 Circular Mil. This means the conversion factor from Circular Mil to Square Millimeter is 0.0005067075.

What is the formula to convert Circular Mil to Square Millimeter?

The formula to convert Circular Mil to Square Millimeter is: mm² = cmil × 0.0005067075. For example, to convert 10 Circular Mil to Square Millimeter, you would multiply 10 by 0.0005067075.

What is a Circular Mil?