# How to Estimate Sewing Time by Machine RPM?

Are you looking for a way to estimate how much time should be taken by a sewing operator to sew a specific length of seam? Read this article to know the method for estimating sewing time.

Machine RPM (revolution per minute) decides how much (minimum) time is required to sew a specific length of seam with specific Stitch per Inch (SPI). If you only consider on the machine time then use the following formula for calculation.

Machine cycle time = SPI X Seam Length (in inch)/machine RPM

How?
SPI specifies number of stitches (needle dips) in each inch of the seam and
RPM specifies how many times a needle dips through fabric per minutes.

A specific seam length gives you how many stitches required to sew complete seam. Use simple mathematics to find machine time required to sew a certain length of fabric.

See the Example:

Machine RPM 2000 (Take a lock stitch Machine), required stitch per inch is 10 and you have to sew 50 inches straight seam (suppose a superimposed seam). So, to sew 50 inches length of a seam total stitches (needle dips) needed = 50 X 10 stitches = 500 stitches

As per machine RPM, machine can make 2000 stitches per minute at its maximum speed. So, to make 500 stitches machine will need only 15 seconds (provided that no stopping during stitching complete 50 inches seam). Now you got the idea. If you think your machine is running at 1000 RPM then in this case machine time will be 30 seconds.

You may think that when sewing a garment operator can’t make it in a single burst. The above formula gives you clear information about the minimum time is needed to machine time if we ignore all other factors.