Millimeters to Inches Converter
Convert millimeters to inches instantly with this free millimeters to inches converter. Enter any value to get an accurate length conversion, plus the formula, the conversion factor and a full reference table.
What is 1 millimeter in inches?
1 millimeter is equal to 0.039370079 inches.
1 ÷ 25.4 = 0.039370079 inches
1 millimeter = 0.0393700787 inches
Millimeters to Inches formula
in = mm ÷ 25.4
The millimeters to inches conversion factor is 0.03937007874, which is exact by definition. 1 millimeter = 0.03937007874 inches, and 1 inch = 25.4 millimeters.
Worked examples
- 2 millimeters = 0.078740157 inches — 2 ÷ 25.4 = 0.078740157 inches
- 6 millimeters = 0.236220472 inches — 6 ÷ 25.4 = 0.236220472 inches
- 10 millimeters = 0.393700787 inches — 10 ÷ 25.4 = 0.393700787 inches
Millimeters to Inches conversion table
Every value below is calculated with the exact conversion factor and rounded for display.
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 mm | 0.03937008 in |
| 2 mm | 0.07874016 in |
| 3 mm | 0.11811024 in |
| 4 mm | 0.15748031 in |
| 5 mm | 0.19685039 in |
| 6 mm | 0.23622047 in |
| 7 mm | 0.27559055 in |
| 8 mm | 0.31496063 in |
| 9 mm | 0.35433071 in |
| 10 mm | 0.39370079 in |
| 12 mm | 0.47244094 in |
| 15 mm | 0.59055118 in |
| 20 mm | 0.78740157 in |
| 25 mm | 0.98425197 in |
| 30 mm | 1.1811024 in |
| 50 mm | 1.9685039 in |
| 75 mm | 2.9527559 in |
| 100 mm | 3.9370079 in |
| 500 mm | 19.685039 in |
| 1,000 mm | 39.370079 in |
When you need to convert millimeters to inches
- Buying furniture, TVs or appliances listed in one system and fitting them into a room measured in the other.
- Following building plans, sewing patterns or DIY instructions written abroad.
- Reading height, screen size or luggage limits when travelling between the US and the rest of the world.
Getting a feel for the scale
A converted number is easier to trust when you can picture it. These reference points let you sanity-check the result at a glance.
Millimeter (mm)
- A credit card is 0.76 mm thick
- A UK 1p coin is about 1.5 mm thick
Inch (in)
- A US quarter is about 1 inch across
- Standard printer paper is 8.5 inches wide
Common mistakes to avoid
- Dividing when you should multiply. Because 1 millimeter = 0.03937 inches, the answer should be smaller than the number you started with.
- Rounding too early. Convert first at full precision, then round the final answer to the precision the task actually needs.
How precise does the answer need to be?
For everyday measurements round to the nearest whole unit or to one decimal place. Machining, sewing and construction usually need at least two decimals — and it is worth measuring in the target unit directly when tolerance matters.
How these units are defined
- Millimeter (mm): One thousandth of a meter; the standard fine unit on metric rulers. This unit's relationship to the SI base unit is exact by definition, so no rounding enters the conversion factor.
- Inch (in): Exactly 25.4 millimeters; the base small unit of US customary and Imperial length. This unit's relationship to the SI base unit is exact by definition, so no rounding enters the conversion factor.
Related conversions
Frequently asked questions
- What is 1 millimeter in inches?
- 1 millimeter is equal to 0.039370079 inches.
- How many millimeters are in one inch?
- There are 25.4 millimeters in 1 inch.
- How do you convert millimeters to inches?
- Multiply the number of millimeters by 0.039370079 — or use the formula in = mm ÷ 25.4.
- What is 6 millimeters in inches?
- 6 millimeters is 0.236220472 inches. 6 ÷ 25.4 = 0.236220472 inches.
- Is the millimeters to inches conversion exact?
- Yes. The relationship is fixed by definition, so 0.03937007874 is an exact conversion factor — only the displayed result is rounded.