How do you convert dots per inch to dots per millimeter?

To convert dots per inch (DPI) to dots per millimeter (dpmm), multiply the measurement in dots per inch by 0.03937 (dots per millimeter = dots per inch × 0.03937).

What is 5 dots per inch in dots per millimeter?

5 dots per inch (5 DPI) is equal to 0.19685 dots per millimeter (0.19685 dpmm).

Which is larger, 1 dot per inch (dpi / ppi) (DPI) or 1 dot per millimeter (dpmm)?

One dot per millimeter (dpmm) is larger than one dot per inch (dpi / ppi) (DPI). Specifically, 1 dpmm equals 25.4 DPI, while 1 DPI is 0.03937 dpmm.

How do I convert back from dots per millimeter (dpmm) (dpmm) to dots per inch (dpi) (DPI)?

To reverse the calculation from dpmm to DPI, multiply your dot per millimeter value by the inverse factor 25.4 (or divide by 0.03937). You can also click the Swap button in the tool above to flip directions in one click.

How many decimal places should I round DPI to dpmm results to?

For everyday comparisons and quick estimates, rounding to 2 decimal places is usually sufficient (for example, 5 DPI ≈ 0.20 dpmm). For engineering, laboratory, or machining specifications, select 4 or 6 decimals—or Scientific (10ⁿ) mode—in the calculator toolbar above.

Dots per Inch to Dots per Millimeter Converter

Enter the image resolution in dots per inch below to convert it to dots per millimeter.

Dots per Millimeter (dpmm) to Dots per Inch (DPI) (dpmm → DPI)

Convert Dots per Inch (DPI) to Dots per Millimeter (dpmm)

Enter a value in dots per inch (dpi) (DPI) to convert to dots per millimeter (dpmm) (dpmm).

Value (DPI)

From

Result

•

0.196850394dots per millimeter (dpmm)

5 DPI = 0.196850394 dpmm

Result updates automatically

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Suggested Conversions

Reference:NIST OWM (SI Units — Length)

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Dot per Inch to Dot per Millimeter Conversion Table

Table showing various dot per inch measurements converted to dots per millimeter. Click any preset value or arrow to load it into the converter.

Dots per Inch (DPI) (DPI)	Dots per Millimeter (dpmm) (dpmm)
1 DPI	0.0393701 dpmm
2 DPI	0.0787402 dpmm
2.5 DPI	0.0984252 dpmm
5 DPI	0.1968504 dpmm
10 DPI	0.3937008 dpmm
15 DPI	0.5905512 dpmm
20 DPI	0.7874016 dpmm
25 DPI	0.984252 dpmm
30 DPI	1.1811024 dpmm
50 DPI	1.9685039 dpmm

How to Convert Dots per Inch to Dots per Millimeter

To convert dots per inch to dots per millimeter, multiply the image resolution by the following conversion ratio: 0.0393701 dots per millimeter/dot per inch.

Since one dot per inch is equal to 0.0393701 dots per millimeter, you can use this simple formula to convert:

dots per millimeter = dots per inch × 0.0393701

The image resolution in dots per millimeter is equal to the image resolution in dots per inch multiplied by 0.0393701.

For example, here's how to convert 5 dots per inch to dots per millimeter using the formula above.

dots per millimeter = (5 DPI × 0.0393701) = 0.1968504 dpmm

How Many Dots per Millimeter Are in a Dot per Inch?

There are 0.0393701 dots per millimeter in a dot per inch, which is why we use this value in the formula above.

1 DPI = 0.0393701 dpmm|1 dpmm = 25.4 DPI

Our dot per inch to dot per millimeter calculator automatically converts your image resolution measurements with full decimal and scientific precision across US customary, imperial, and SI metric standards.

Dots per Inch and dots per millimeter are both units used to measure image resolution. Keep reading to learn more about each unit.

What Is a Dot per Inch?

A dot per inch is a unit of image resolution equal to 39.3700787 dots per meter (dpm), the base unit for image resolution. Standard display and print resolution unit (1 DPI ≈ 39.37 dots/m). [1]

The dot per inch is classified as a US customary unit of image resolution. Dots per Inch can be abbreviated as DPI; for example, 1 dot per inch can be written as 1 DPI.

When working with dots per inch (DPI) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.

In practice, dots per inch (DPI) are widely used across standard image resolution applications within US customary workflows, engineering documentation, and technical data sheets.

Learn more about dots per inch in our Digital Image Resolution Converter.

What Is a Dot per Millimeter?

A dot per millimeter is a unit of image resolution equal to 1,000 dots per meter (dpm), the base unit for image resolution. Thermal label printer resolution unit (1 dpmm = 25.4 DPI). [2]

The dot per millimeter is classified as a metric and SI-compatible unit of image resolution. Dots per Millimeter can be abbreviated as dpmm; for example, 1 dot per millimeter can be written as 1 dpmm.

When working with dots per millimeter (dpmm) in formulas or technical specifications, always verify whether your target system uses SI metric, US customary, or British imperial standards.

In practice, dots per millimeter (dpmm) are widely used across large-scale industrial, bulk, and macro-level image resolution specifications within SI metric workflows, engineering documentation, and technical data sheets.

Learn more about dots per millimeter in our Digital Image Resolution Converter.

When converting image resolution between dots per inch (DPI) and dots per millimeter (dpmm), keep full floating-point precision (1 DPI = 0.0393701 dpmm; 1 dpmm = 25.4 DPI) during intermediate calculations and round only the final dot per millimeter figure to match your instrument tolerance.

More Dot per Inch & Dot per Millimeter Conversions

Need to calculate in the opposite direction? Use our dots per millimeter (dpmm) to dots per inch (dpi) calculator to switch your starting unit immediately. You can also explore related tools such as converting dots per millimeter (dpmm) to dots per inch (dpi), converting dots per meter to dots per millimeter (dpmm), or converting dots per inch (dpi) to dots per meter.

Convert from Dots per Inch

Convert to Dots per Millimeter

Frequently Asked Questions

There are 0.03937 dots per millimeter (dpmm) in 1 dot per inch (DPI). Conversely, 1 dot per millimeter (dpmm) is equal to 25.4 dots per inch (DPI).

Digital Image Resolution Converter

Quick Info

Direct Factor: 1 dot per inch (dpi / ppi) (DPI) equals 0.03937 dots per millimeter (dpmm) (dpmm).
Inverse Factor: 1 dot per millimeter (dpmm) equals 25.4 dots per inch (dpi) (DPI).
Formula: dots per millimeter (dpmm) = dots per inch (dpi) ÷ 25.4.
Verified Precision: Anchored to official NIST SP 811 and ISO/IEC 80000 standards.

Units Comparison

Dot per Inch (DPI / PPI) (DPI)

Standard display and print resolution unit (1 DPI ≈ 39.37 dots/m).

Dot per Millimeter (dpmm)

Thermal label printer resolution unit (1 dpmm = 25.4 DPI).

Dot per Meter (dpm)

SI spatial resolution unit (dots or pixels per meter).

References

[1]NIST OWM · SI Units — Length
Source
[2]BIPM · SI Base Unit: Metre (m)
Source
[3]NIST HB 133 · NIST Handbook 133 (2019 Ed.)
Source

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References

NIST · BIPM · ISO

[1]
NIST OWM (SI Units — Length)·Digital Image Resolution Metrology Standard — Dots per Inch (DPI) (DPI) to Dots per Millimeter (dpmm) (dpmm)
NIST OWM Standard
[2]
BIPM (SI Base Unit: Metre (m))·Unit Specifications: Dot per Inch (DPI / PPI) (DPI) & Dot per Millimeter (dpmm)
BIPM Specification
[3]
NIST HB 133 (NIST Handbook 133 (2019 Ed.))·Conversion Factors & Mathematical Basis (DPI to dpmm)
NIST HB 133 Reference

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