Stitches per inch to millimeters per stitch
Type a value in SPI to get it in mm instantly.
2.117mm
That's 1.41× as long as fine fabric, while a standard seam is 1.18× longer.
Convert the other way: mm to SPI
What it means
How long is that stitch?
For straight stitch. Thread tension and fabric thickness change the stitch you actually get by a little.
The math
How to convert SPI to mm
mm per stitch = 25.4 ÷ SPI; SPI = 25.4 ÷ mm.
Example: 12 SPI = 2.11667 mm.
Every unit
That stitch in every unit
Tables
SPI to mm conversion table
| SPI | mm |
|---|---|
| 5 SPI | 5.08 mm |
| 6 SPI | 4.23333 mm |
| 7 SPI | 3.62857 mm |
| 8 SPI | 3.175 mm |
| 9 SPI | 2.82222 mm |
| 10 SPI | 2.54 mm |
| 11 SPI | 2.30909 mm |
| 12 SPI | 2.11667 mm |
| 14 SPI | 1.81429 mm |
| 16 SPI | 1.5875 mm |
| 18 SPI | 1.41111 mm |
| 20 SPI | 1.27 mm |
mm to SPI conversion table
| mm | SPI |
|---|---|
| 1.27 mm | 20 SPI |
| 1.41 mm | 18.0142 SPI |
| 1.59 mm | 15.9748 SPI |
| 1.81 mm | 14.0331 SPI |
| 2.12 mm | 11.9811 SPI |
| 2.31 mm | 10.9957 SPI |
| 2.54 mm | 10 SPI |
| 2.82 mm | 9.00709 SPI |
| 3.18 mm | 7.98742 SPI |
| 3.63 mm | 6.99725 SPI |
| 4.23 mm | 6.00473 SPI |
| 5.08 mm | 5 SPI |
Quick answers
Quick answers
- How many mm is 1 SPI?
- 1 SPI is 25.4 mm.
- How many mm is 10 SPI?
- 10 SPI is 2.54 mm.
- How many mm is 12 SPI?
- 12 SPI is 2.11667 mm.
The units
About these units
Stitches per inch (SPI)
How many stitches fit in an inch.
Millimeters per stitch (mm)
Stitch length as machines set it.
Keep going