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TPM to TPI converter
To convert TPM to TPI, multiply by 0.0254 (or divide by 39.37). So 800 TPM is 20.32 TPI, and 20 TPI is 787.4 TPM.
Type in either box; the other updates.
Formula
TPI = TPM × 0.0254 · TPM = TPI × 39.37
One inch is exactly 0.0254 m, so turns per inch are turns per metre multiplied by 0.0254.
Example: A ring-spun yarn twisted at 800 TPM: 800 × 0.0254 = 20.32 TPI.
TPM to TPI chart
| TPM | TPI |
|---|---|
| 200 | 5.08 |
| 300 | 7.62 |
| 400 | 10.16 |
| 500 | 12.7 |
| 600 | 15.24 |
| 650 | 16.51 |
| 700 | 17.78 |
| 750 | 19.05 |
| 800 | 20.32 |
| 850 | 21.59 |
| 900 | 22.86 |
| 1,000 | 25.4 |
| 1,100 | 27.94 |
| 1,200 | 30.48 |
TPI to TPM chart
| TPI | TPM |
|---|---|
| 5 | 196.85 |
| 10 | 393.7 |
| 12 | 472.44 |
| 15 | 590.55 |
| 18 | 708.66 |
| 20 | 787.4 |
| 22 | 866.14 |
| 25 | 984.25 |
| 30 | 1181.1 |
Questions buyers ask
Is TM the same as TPM?
No. TM usually means twist multiplier (TPI ÷ √Ne). Use the twist multiplier calculator for that.
Which unit do Indian mills quote?
Both appear. Spec sheets often give TPI for cotton counts and TPM for filament and technical yarns.
Related tools
Twist calculator · Twist multiplier calculator · Yarn count converter · All free tools
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