40 centimeters to millimeters
40 centimeters = 400 millimeters
Rounded to a practical precision: 400 mm.
Guide & FAQHow the calculation works · Nearby values · About these units · Frequently asked questions
How the calculation works
One centimeter is 10 millimeters, so:
40 cm × 10 = 400 mmReversing it, 400 millimeters ÷ 10 returns 40 centimeters.
Nearby values
| Centimeters | Millimeters |
|---|---|
| 36 cm | 360 mm |
| 37 cm | 370 mm |
| 38 cm | 380 mm |
| 39 cm | 390 mm |
| 40 cm | 400 mm |
| 41 cm | 410 mm |
| 42 cm | 420 mm |
| 43 cm | 430 mm |
| 44 cm | 440 mm |
In everyday terms, 40 centimeters is about the long edge of a sheet of A4 paper.
About these units
Centimeter (cm) — A centimetre is one hundredth of a metre, the everyday metric unit for body measurements and small objects.
Millimeter (mm) — A millimetre is one thousandth of a metre and is the default unit on engineering drawings and rulers.
Frequently asked questions
How many millimeters is 40 centimeters?
40 centimeters is 400 millimeters.
How do I convert centimeters to millimeters myself?
Multiply by 10. To go back, divide by 10 — or multiply by 0.1.
Is this figure exact?
The conversion factor between the centimeter and the millimeter is fixed by definition. The figure above is rounded for readability; the converter carries full precision.
Convert other values
Full centimeters to millimeters converter · All length converters