Millimetres per Year to Inches per Year (mm/y to ipy)
1 millimetre per year (mm/y) = 0.03937007874 inches per year (ipy). 1 ipy = 25.4 mm/y. Example: 15 mm/y = 15 × 0.03937007874 = 0.5905511811 ipy.
Also searched as millimetres per year to ipy, millimetres per year in ipy, millimetres per year into inches per year, mm/y to ipy, mm/y in inches per year, mm/y into inch per year, millimetre per year to inch per year, mm/y to inches per year converter, millimeters per year to inches per year and how many inches per year in a millimetre per year.
1 mm/y = 0.03937007874 ipy
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk millimetre per year to inch per year converter to paste a column from Excel.
How to Convert Millimetre per Year to Inch per Year
- 1 mm/y = 0.03937007874 ipy
- 1 ipy = 25.4 mm/y
- Example: convert 15 mm/y to ipy: 15 mm/y = 15 × 0.03937007874 ipy = 0.5905511811 ipy
Formula
ipy = mm/y × 0.03937007874016
or ipy = mm/y ÷ 25.4
Derivation from SI units:
- Thickness loss in millimetres per year of exposure (the reference unit for corrosion rate)
- 1 ipy = 25.4 mm/y = 1000 mpy (exact)
Both units are defined exactly, so the factor is exact. Millimetre per Year definition: millimetre per year; Inch per Year definition: inch per year.
Worked examples
- A reading of 0.05 mm/y converts to 0.001968503937 ipy.
0.05 mm/y × 0.03937007874 = 0.001968503937 ipy - A value of 0.5 mm/y is 0.01968503937 ipy.
0.5 mm/y × 0.03937007874 = 0.01968503937 ipy
Millimetre per Year to Inch per Year conversion table
| Millimetres per Year (mm/y) | Inches per Year (ipy) |
|---|---|
| 0.001 mm/y | 0.00003937007874 ipy |
| 0.01 mm/y | 0.0003937007874 ipy |
| 0.025 mm/y | 0.0009842519685 ipy |
| 0.05 mm/y | 0.001968503937 ipy |
| 0.1 mm/y | 0.003937007874 ipy |
| 0.13 mm/y | 0.005118110236 ipy |
| 0.25 mm/y | 0.009842519685 ipy |
| 0.5 mm/y | 0.01968503937 ipy |
| 1 mm/y | 0.03937007874 ipy |
| 1.27 mm/y | 0.05 ipy |
| 5 mm/y | 0.1968503937 ipy |
Where it's used
Millimetres per Year are used for corrosion coupon and weight-loss tests, while inches per year appear in older corrosion resistance tables. Both measure corrosion rate (thickness loss per year), so the conversion is a fixed factor.
Millimetre per Year to other corrosion rate units
| Conversion | 1 mm/y equals |
|---|---|
| millimetre per year to inch per year | 0.03937007874 ipy |
| millimetre per year to mil per year | 39.37007874 mpy |
| millimetre per year to micrometre per year | 1000 µm/y |
Frequently asked questions
How many inches per year are in 1 millimetre per year?
1 mm/y = 0.03937007874 ipy.
How do I convert millimetres per year to inches per year?
Multiply the value in mm/y by 0.03937007874, or divide it by 25.4. For example, 15 mm/y × 0.03937007874 = 0.5905511811 ipy.
Is the mm/y to ipy conversion exact?
Yes. Both units are defined exactly, so the ratio is exact; its decimal form does not terminate and is shown here to 10 significant figures (more with the precision selector).
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology .
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "inch".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Millimetres per Year to Inches per Year (mm/y to ipy). Retrieved October 25, 2026, from https://scientificconverters.com/corrosion-rate/millimeters-per-year-to-inches-per-year/
IEEE
Scientific Converters, "Millimetres per Year to Inches per Year (mm/y to ipy)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/corrosion-rate/millimeters-per-year-to-inches-per-year/