How do I convert TPI to TPM?

Multiply turns per inch by 39.37. 20 TPI = 787.4 TPM.

How do I convert TPM to TPI?

Divide turns per metre by 39.37. 800 TPM = 20.3 TPI.

How is TPI calculated from the twist multiplier?

TPI = TM x square root of the English count (Ne). A 30 Ne yarn at TM 3.8 has 3.8 x 5.48 = 20.8 TPI.

Yarn Twist (TPI/TPM) Calculator

Convert TPI to TPM (x 39.37) and calculate yarn twist per inch and per metre from the twist multiplier and count, with typical twist multipliers for hosiery and warp yarn.

Twist multiplier (TM)Yarn count (Ne)

Twist

20.8TPI

Twist

819TPM

The formula

TPI = TM x sqrt(Ne); TPM = TPI x 39.37.

Worked example

Twist multiplier (TM): 3.8, Yarn count: 30 Ne. Result: Twist = 20.8 TPI; Twist = 819 TPM.

Assumptions

English (cotton) twist multiplier convention; typical TM: hosiery 3.2-3.8, warp 4.2-4.8.

Questions

How do I convert TPI to TPM?: Multiply turns per inch by 39.37. 20 TPI = 787.4 TPM.
How do I convert TPM to TPI?: Divide turns per metre by 39.37. 800 TPM = 20.3 TPI.
How is TPI calculated from the twist multiplier?: TPI = TM x square root of the English count (Ne). A 30 Ne yarn at TM 3.8 has 3.8 x 5.48 = 20.8 TPI.

In the platform

Intelactory records which yarn lot went into which fabric roll, dye batch and carton as the work happens, so a count or GSM question traces back to its source.

See lot traceability Pricing

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