Convert common metal coating thickness units for paint, plating, galvanizing and other coating specifications.
Coating Thickness Conversion
The converter uses exact unit relationships. One mil equals 25.4 micrometres, while one millimetre equals 1,000 micrometres.
Ready to convert. Press Convert Coating Thickness.
Conversion Result
Converted Thickness
—
Micrometres
—
µm
Millimetres
—
mm
Mils
—
mil
Inches
—
in
Centimetres
—
cm
Coating Thickness Visualization
Coating thickness
Simplified metal substrate and coating cross-section
The illustration is conceptual and not to scale.
Common Unit Equivalents
Metric Units
1 millimetre1,000 µm
1 micrometre0.001 mm
1 centimetre10 mm
1 nanometre0.001 µm
Imperial Units
1 mil0.001 in
1 mil25.4 µm
1 inch1,000 mil
1 inch25,400 µm
All Unit Conversions
Unit
Symbol
Equivalent in µm
Equivalent in mm
Equivalent in mil
Equivalent in inches
Coating Thickness Formulas
The converter first converts the input to micrometres and then converts the result into the requested unit.
1 mm = 1,000 µm
1 mil = 25.4 µm
1 inch = 25,400 µm
1 cm = 10,000 µm
1 µm = 1,000 nm
Practical Coating Thickness Reference
Coating thickness is commonly specified in micrometres or mils depending on the industry, coating system and specification.
Thickness
Micrometres
Millimetres
Mils
0.5 mil
12.7 µm
0.0127 mm
0.5 mil
1 mil
25.4 µm
0.0254 mm
1 mil
2 mil
50.8 µm
0.0508 mm
2 mil
3 mil
76.2 µm
0.0762 mm
3 mil
5 mil
127 µm
0.127 mm
5 mil
10 mil
254 µm
0.254 mm
10 mil
20 mil
508 µm
0.508 mm
20 mil
40 mil
1,016 µm
1.016 mm
40 mil
Important Limitations
This tool performs mathematical unit conversion only.
It does not measure coating thickness.
It does not determine whether a coating meets a specification.
It does not calculate dry-film thickness from wet-film thickness.
It does not account for coating shrinkage or curing effects.
It does not determine paint coverage or spreading rate.
Actual coating inspection should use a suitable calibrated measurement method.
Project specifications and coating manufacturer requirements take precedence.
Use the converted value as a unit-reference result. For quality-control decisions, use the appropriate coating thickness measurement equipment and the applicable project or coating specification.
Frequently Asked Questions
What does the Metal Coating Thickness Converter do?
It converts coating thickness between micrometres, millimetres, mils, inches, centimetres and nanometres.
How many micrometres are in one mil?
One mil equals exactly 25.4 micrometres.
How many mils are in one millimetre?
One millimetre equals approximately 39.3701 mils.
How many micrometres are in one millimetre?
One millimetre equals exactly 1,000 micrometres.
Is a mil the same as a millimetre?
No. A mil is one thousandth of an inch, while a millimetre is a metric unit. One mil is approximately 0.0254 mm.
Can this tool measure coating thickness?
No. It only converts an existing thickness value between units.