How to use this calculator
- Enter or choose machine speed.
- Enter or choose feeders.
- Enter or choose needles.
- Enter or choose stitch length.
- Enter or choose yarn count.
- The production per hour updates as you type. Use Copy result or Share to keep it.
Method
Yarn m/min = RPM × Feeders × Needles × SL(mm) ÷ 1,000; kg/h = Yarn m/min × 60 × tex ÷ 1,000,000 × Efficiency
- SL
- stitch (loop) length in mm
- tex
- grams per 1,000 m; tex = 590.54 ÷ Ne = denier ÷ 9 = 1,000 ÷ Nm
Worked example
- Yarn per minute = 25 × 90 × 2,640 × 2.8 mm = 16,632 m.
- At 20 tex: 16,632 × 60 × 20 ÷ 1,000,000 = 19.958 kg/h.
- At 85%: 16.96 kg/h; over 24 h: 407.15 kg.
A 30″ 28G machine with 90 feeders at 25 RPM, 2.8 mm stitch length and 20 tex yarn makes about 17 kg an hour, 407 kg a day.
What the result means
Compare the result with actual roll weights. A consistent gap usually means the real efficiency or stitch length differs from the figure used.
Assumptions and limits
- Every feeder is active and knits on every needle (single jersey). For rib or interlock with two needle beds, enter the total needles that knit per feeder.
- Spandex or plated yarns need each yarn calculated separately and added.
- Does not include yarn waste or moisture regain.
Questions
How do I convert Ne to tex?
tex = 590.54 ÷ Ne, because Ne counts 840-yard hanks per pound.
Where do I get the stitch length?
Measure the yarn length in 100 needles of unravelled fabric, or use the setting from your knitting programme.