How to estimate the thread usage.

There is no getting away from the fact that trying to estimate how much thread you need for a design is near impossible based on maths alone.
The only reliable guide to how much thread of each colour will be needed in a chart, is to stitch it.
And even then, different stitching styles, tensions, and wastage due to pulling out and rework, all contribute to the end result.
Some stitchers source 18 inch pre-packaged threads while others buy bulk spools or 8m Skeins.

Why is it complicated?
Embroidery floss usually comes in 6-stranded packaging, either in skeins, on spools, or ready cut.
When you stitch, you might have 1, 2,3 or more strands in the needle at once. (This is 1, 2, or 3 ply)
And you may mix and match within a design for effect.

So if you stitch a simple line of backstitch , one inch in length , without any of it going behind the cloth, you could start by assuming thats ‘one inch’ of floss.
But if you use 2 ply, there are actually two inches of floss used.

An 18 inch pre-pack of 6 stranded cotton contains 3 x 18inch lengths of 2ply
Or 6 x 18 inch lengths of 1 ply

In total,
108 inches of single ply floss.
54 inches of 2 ply
36 inches of 3 ply

Some people describe the amount of thread in inches, some in bundles, and some in skeins: any estimate always needs to be aware of the number of strands in use too.
The size of the stitches affects the ‘amount per stitch’, and the larger the stitch, the less is lost turning into a new direction, or around the back of the cloth.

It would seem there is no simple 100 stitches = this amount of thread, simply because you need to qualify what type of stitches (size, ply, wastage) and what type of ‘thread’ (length , bundle, skein...)

What can be done?

To get a feel for how much thread will be used,

• start by using 2 ply, and stitching a 10 x 10 area on your chosen material,
noting how many stitches-to-the-inch you are working.
(Ignore the h.p.i of the material, we are only concerned with how many stitches per inch)

That will generate 100 stitches.
• Look at the simple length of floss used.

If that was 36 inches, then each stitch took
36/100 inches = 0.36 inches of floss on average, assuming ideal stitching and no waste.
This is our ‘inches per stitch’ value, and we can start by multiplying that by the number of stitches of that colour in any chart.
(It will probably need to be increased to account for wastage, cut ends, rework etc.. the amount to increase by will be your decision.)

If we are using a mixture of 1,2, or 3 ply then it may make sense to
multiply the amount by the number of strands and express the length in terms of a single strand.
In that example, 100 stitches = 36 inches of 2 ply or
72 inches expressed in single ply
(e.g. If some of your work is single ply and some is 2 ply, then the 2 ply work will use thread at twice the rate of single ply.)

Our software allows you to adjust the estimation factor used for calculating the length needed.
We ask for the length per stitch, and this varies based on the stitches per inch.

At 14 stitches per inch, the value (as above) might be 0.36 per stitch per ply.
At 6 stitches per inch, the value might be 0.36 x 14 / 6 = 0.84 per stitch per ply.
But the further we move away from 14 stitches per inch, the less accurate that becomes, and so its a good idea to perform the 100 stitches using the stitch size you will actually be working with.

How many skeins?

Taking the length in single strands, to get the number of skeins:
Multiply the length of the skein by 6 to account for the 6 strands. (e.g. 8m x 6 = 48 metres)
If need be, change metres to inches (48 metres = 1889 inches)
Divide your estimated length of single ply by that figure. (e.g. 2500 inches / 1889 inches = 1.36 skeins)

If you prefer to work using ‘always 2 ply’ then your estimated length will have been 1250 inches of 2 ply.
The skein will be 8 x 3 metres = 24 metres of 2ply
The estimated number of skeins will be 1250/945 inches = 1.36 skeins

From the 2015 editions onwards, we offer more options for you to set the estimates more accurately.
In the preferences dialog, you can now set the values independently for your choice of stitches-per-inch.

After you have worked your estimation as above, enter your figures in our screen:

And if you want the thread estimate to go up by every strand you use, (e.g. 2 strands reports 10 inches, 3 strands reports 15 inches for the same number of stitches), then tick the ‘Multiply length by strands’ option.

Other opinions

Classic Cross Stitch (
Some of that information is copied below

An estimate as to how many stitches can be obtained from an 8 m skein of 6 ply floss for various stitches per inch on canvas, based on figures obtained for different stitch counts.

 Two Ply Count Generous Average Thrifty 18 1800 2000 2300 16 1600 1800 2050 14 1400 1600 1800 12 1200 1400 1550 3 Ply Count Generous Average Thrifty 12 800 900 1000 10 650 750 850 8 450 500 550

8m gives 24m of 2 ply.
24m = 944 inches

So , based on Average usage, these figures suggest a starting point of
18 .. 0.472 in per stitch
16 .. 0.5244 in per stitch
14 .. 0.59 in per stitch
12 .. 0.674 in per stitch

..before we make allowances for wastage.