How do I estimate remaining yarn length by weight?

Subtract container tare from measured gross mass to get net yarn mass. Divide net mass by the original skein’s yarn-only mass, then multiply by its original length. A 100 g skein labeled 200 m gives 50 m remaining when net yarn mass is 25 g.

How should I enter container tare?

Enter the mass of anything supporting the yarn on the scale, such as a bowl or core, in the same units as gross mass. Gross mass of 35 g minus a 10 g container gives 25 g of yarn. If your scale already zeroed the container, enter tare 0 to avoid subtracting twice.

Can I mix grams, ounces, metres and yards?

Yes. Original mass and measured mass may use grams or avoirdupois ounces independently. Original and output length may use metres, yards or feet. The calculator uses exact unit definitions internally. Changing an input unit reinterprets the unchanged number; changing output length units converts results.

Why can the estimate exceed the original skein length?

Net yarn mass may exceed the original mass because of a unit or measurement mistake, a container that was not excluded, or multiple skeins. The calculator flags this and retains the proportional result rather than capping it. The visual bar stops at 100%, but the numeric percentage and length do not.

Does tare apply to the comparison table?

No. Comparison entries are net yarn masses that already exclude containers. Each is multiplied by the same length-per-mass ratio, without subtracting tare again. Enter up to 20 values; duplicate masses appear once.

Can this tell me how much yarn a garment needs?

No. It estimates length from measured mass assuming uniform linear density. It does not use garment-size, stitch, gauge or project-consumption tables. Yarn thickness variation, moisture and measurement accuracy affect the estimate.

How precise are the calculations and exports?

Inputs support six decimal places and values up to 1,000,000 in their selected units. Arithmetic and unit conversions use exact fractions; displayed estimates round to six decimal places. Tiny positive values may display as zero. CSV includes the measured result, all comparisons and exact output-length fractions; TXT includes input measurements and tare. Inputs stay local and are not saved automatically.

Yarn Length Calculator

Use a known skein’s mass and length to estimate yarn remaining on your scale. Subtract container tare, compare net masses, and export estimates in metres, yards or feet.

Original skein

Full skein yarn massFull skein mass unitsOriginal yarn lengthOriginal length units

Use the yarn-only mass and corresponding length for the same original skein. Exclude its label, wrapper, core and container. You can enter label values or your own measurements; the estimate inherits their accuracy.

Remaining yarn on the scale

Measured gross massMeasured mass unitsContainer tareResult length units

Gross mass includes the remaining yarn and anything supporting it on the scale. Enter that support’s mass as tare. If the scale is already zeroed with the container, use tare 0 here. Gross and tare use the same units.

Changing an input unit reinterprets its unchanged number; changing result length units converts outputs. Values support six decimal places and up to 1,000,000 selected units. Original mass and length must be positive; gross and tare may be zero.

Comparison net yarn masses (g)

Enter up to 20 net yarn masses separated by commas or spaces. These already exclude containers; tare is not subtracted again. Repeated masses appear once. Leave blank for no comparisons.

Estimated remaining length50m

Net yarn mass25g after tare

Length per unit mass2m / g

Proportion of the original skein

25% of original yarn mass

100% is the original skein mass. The bar is capped at 100%; the numeric result is not. With uniform length per unit mass, the same proportion applies to length.

Net mass = 25 − 0 = 25 g
Length estimate = net mass ÷ full yarn mass × original length
≈ 25 ÷ 100 × 200 = 50 m

The calculation above converts full mass to g and original length to m. Displayed values round to six decimal places; calculations use unrounded fractions. Tiny positive estimates can display as zero. Yarn thickness changes, moisture, labels and scale precision can affect the physical estimate.

Compare net yarn masses

Net mass (g)	Estimated length (m)	Original mass (%)
0	0	0
10	20	10
25	50	25
50	100	50
75	150	75
100	200	100

Scroll horizontally on narrow screens. Every row uses the same original mass-to-length ratio. These comparisons do not estimate the yarn needed for a garment or project.

Calculation summary

Yarn length estimate
Full skein yarn mass: 100 g
Original yarn length: 200 m
Gross mass: 25 g
Container tare: 0 g
Net yarn mass: 25 g
Estimated remaining length: 50 m
Length per unit mass: 2 m/g
Net mass / full yarn mass: 25%
Exact remaining length (m): 50/1

Comparison net mass (g) | Estimated length (m) | Percent of full mass
0 | 0 | 0%
10 | 20 | 10%
25 | 50 | 25%
50 | 100 | 50%
75 | 150 | 75%
100 | 200 | 100%

Assumes uniform yarn length per unit mass and accurate measurements. Exact decimal arithmetic and unit factors; displayed estimates round to six decimal places. No garment or project-consumption recommendation.
Comparison masses already exclude containers; tare is not subtracted again.

CSV includes the measured result, every comparison and exact length fractions in the selected output units. TXT includes the input measurements and tare.

Assumes uniform yarn length per unit mass and accurate measurements. Exact decimal arithmetic and unit factors; displayed estimates round to six decimal places. No garment or project-consumption recommendation. Inputs stay in your browser and are not automatically saved.

Common questions

How do I estimate remaining yarn length by weight?: Subtract container tare from measured gross mass to get net yarn mass. Divide net mass by the original skein’s yarn-only mass, then multiply by its original length. A 100 g skein labeled 200 m gives 50 m remaining when net yarn mass is 25 g.
How should I enter container tare?: Enter the mass of anything supporting the yarn on the scale, such as a bowl or core, in the same units as gross mass. Gross mass of 35 g minus a 10 g container gives 25 g of yarn. If your scale already zeroed the container, enter tare 0 to avoid subtracting twice.
Can I mix grams, ounces, metres and yards?: Yes. Original mass and measured mass may use grams or avoirdupois ounces independently. Original and output length may use metres, yards or feet. The calculator uses exact unit definitions internally. Changing an input unit reinterprets the unchanged number; changing output length units converts results.
Why can the estimate exceed the original skein length?: Net yarn mass may exceed the original mass because of a unit or measurement mistake, a container that was not excluded, or multiple skeins. The calculator flags this and retains the proportional result rather than capping it. The visual bar stops at 100%, but the numeric percentage and length do not.
Does tare apply to the comparison table?: No. Comparison entries are net yarn masses that already exclude containers. Each is multiplied by the same length-per-mass ratio, without subtracting tare again. Enter up to 20 values; duplicate masses appear once.
Can this tell me how much yarn a garment needs?: No. It estimates length from measured mass assuming uniform linear density. It does not use garment-size, stitch, gauge or project-consumption tables. Yarn thickness variation, moisture and measurement accuracy affect the estimate.
How precise are the calculations and exports?: Inputs support six decimal places and values up to 1,000,000 in their selected units. Arithmetic and unit conversions use exact fractions; displayed estimates round to six decimal places. Tiny positive values may display as zero. CSV includes the measured result, all comparisons and exact output-length fractions; TXT includes input measurements and tare. Inputs stay local and are not saved automatically.