Convert Mils per Year to Inches per Year (mpy to ipy)
1 mil per year (mpy) = 0.001 inches per year (ipy). 1 ipy = 1000 mpy. Example: 15 mpy = 15 × 0.001 = 0.015 ipy.
Also searched as mils per year to ipy, mils per year in ipy, mils per year into inches per year, mpy to ipy, mpy in inches per year, mpy into inch per year, mil per year to inch per year, mpy to inches per year converter and how many inches per year in a mil per year.
1 mpy = 0.001 ipy
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk mil per year to inch per year converter to paste a column from Excel.
How to Convert Mil per Year to Inch per Year
- 1 mpy = 0.001 ipy
- 1 ipy = 1000 mpy
- Example: convert 15 mpy to ipy: 15 mpy = 15 × 0.001 ipy = 0.015 ipy
Formula
ipy = mpy ÷ 1000
Derivation from SI units:
- 1 mpy = 0.001 in per year = 0.0254 mm/y (exact)
- 1 ipy = 25.4 mm/y = 1000 mpy (exact)
- 1 mpy = 0.0254 mm/y ÷ 25.4 mm/y per ipy = 0.001 ipy
Both units are defined exactly, so the factor is exact. Mil per Year definition: mil per year; Inch per Year definition: inch per year.
Worked examples
- A reading of 2 mpy converts to 0.002 ipy.
2 mpy × 0.001 = 0.002 ipy - A value of 10 mpy is 0.01 ipy.
10 mpy × 0.001 = 0.01 ipy
Mil per Year to Inch per Year conversion table
| Mils per Year (mpy) | Inches per Year (ipy) |
|---|---|
| 0.1 mpy | 0.0001 ipy |
| 0.5 mpy | 0.0005 ipy |
| 1 mpy | 0.001 ipy |
| 2 mpy | 0.002 ipy |
| 3 mpy | 0.003 ipy |
| 5 mpy | 0.005 ipy |
| 10 mpy | 0.01 ipy |
| 20 mpy | 0.02 ipy |
| 50 mpy | 0.05 ipy |
| 100 mpy | 0.1 ipy |
Where it's used
Mils per Year are used for US oil, gas and process industry corrosion monitoring, 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.
Mil per Year to other corrosion rate units
| Conversion | 1 mpy equals |
|---|---|
| mil per year to inch per year | 0.001 ipy |
| mil per year to millimetre per year | 0.0254 mm/y |
| mil per year to micrometre per year | 25.4 µm/y |
Frequently asked questions
How many inches per year are in 1 mil per year?
1 mpy = 0.001 ipy.
How do I convert mils per year to inches per year?
Multiply the value in mpy by 0.001, or divide it by 1000. For example, 15 mpy × 0.001 = 0.015 ipy.
Is the mpy to ipy conversion exact?
Yes. Both units are defined exactly, and 1 mpy is exactly 0.001 ipy.
Sources
- 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, "mil".
- 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). Convert Mils per Year to Inches per Year (mpy to ipy). Retrieved October 25, 2026, from https://scientificconverters.com/corrosion-rate/mils-per-year-to-inches-per-year/
IEEE
Scientific Converters, "Convert Mils per Year to Inches per Year (mpy to ipy)," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/corrosion-rate/mils-per-year-to-inches-per-year/