Grainline Shrinkage Adjustment Calculator
Shrinkage is not the same in both directions. On a fabric losing 5% lengthwise (warp) and 3% crosswise (weft), a piece that has to finish at 100 × 50 cm is cut at 100 ÷ 0.95 = 105.3 cm by 50 ÷ 0.97 = 51.5 cm. That is 5.3 cm going into the wash lengthwise — and adding 5% instead, for 105 cm, comes out slightly short. The correct operation is to divide, not to add.
Your numbers
Cut length
105.3cm
Cut width
51.5cm
Extra to buy
5.3cm
Formula
Cut length = Finished length ÷ (1 − Lengthwise shrinkage ÷ 100), Cut width = Finished width ÷ (1 − Crosswise shrinkage ÷ 100)
The lengthwise figure is usually the bigger one, because weaving and finishing hold the warp under tension; denim often splits 3–10% lengthwise against 1–2% across. Treat this as the fallback for fabric you genuinely cannot pre-wash, such as a knit that has to be cut as it comes off the roll. Washing before cutting removes the guesswork and is always more accurate. Some fabrics also keep shrinking into the second and third wash, so trusting a single wash test can leave the garment shorter again later.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Finished length (cm)The length when finished. | 100 | 1 and up |
| Finished width (cm)The width when finished, before any seam or fold allowance. | 50 | 1 and up |
| Lengthwise shrinkage (%)Shrinkage along the warp; usually the larger of the two directions. | 5 | 0 ~ 30 |
| Crosswise shrinkage (%)Shrinkage across the weft, the fabric's width direction. | 3 | 0 ~ 30 |
Step by step
Quick reference table
Results when only Finished length (cm) changes and everything else stays put.
| Finished length (cm) | Cut length (cm) | Cut width (cm) | Extra to buy (cm) |
|---|---|---|---|
| 50 | 52.6 | 51.5 | 2.6 |
| 75 | 78.9 | 51.5 | 3.9 |
| 100 | 105.3 | 51.5 | 5.3 |
| 150 | 157.9 | 51.5 | 7.9 |
| 200 | 210.5 | 51.5 | 10.5 |
What each result means
| Result | At default values |
|---|---|
| Cut length (cm)The length to cut, finished length plus allowance. | 105.3 |
| Cut width (cm)The width to cut — finished size plus allowance. | 51.5 |
| Extra to buy (cm)The extra to buy so shrinkage does not leave you short. | 5.3 |
Common mistakes
The lengthwise figure is usually the bigger one, because weaving and finishing hold the warp under tension; denim often splits 3–10% lengthwise against 1–2% across. Treat this as the fallback for fabric you genuinely cannot pre-wash, such as a knit that has to be cut as it comes off the roll. Washing before cutting removes the guesswork and is always more accurate. Some fabrics also keep shrinking into the second and third wash, so trusting a single wash test can leave the garment shorter again later.
Glossary
- Finished length
- The length when finished.
- Finished width
- The width when finished, before any seam or fold allowance.
- Lengthwise shrinkage
- Shrinkage along the warp; usually the larger of the two directions.
- Crosswise shrinkage
- Shrinkage across the weft, the fabric's width direction.
- Cut length
- The length to cut, finished length plus allowance.
- Cut width
- The width to cut — finished size plus allowance.
- Extra to buy
- The extra to buy so shrinkage does not leave you short.
Frequently asked questions
Q. How is Grainline Shrinkage Adjustment Calculator calculated?
Cut length = Finished length ÷ (1 − Lengthwise shrinkage ÷ 100), Cut width = Finished width ÷ (1 − Crosswise shrinkage ÷ 100) — Shrinkage is not the same in both directions. On a fabric losing 5% lengthwise (warp) and 3% crosswise (weft), a piece that has to finish at 100 × 50 cm is cut at 100 ÷ 0.95 = 105.3 cm by 50 ÷ 0.97 = 51.5 cm. That is 5.3 cm going into the wash lengthwise — and adding 5% instead, for 105 cm, comes out slightly short. The correct operation is to divide, not to add.
Q. Can you walk through an example?
With Finished length 100cm, Finished width 50cm, Lengthwise shrinkage 5%, Crosswise shrinkage 3%, the answer is Cut length 105.3cm.
Q. What do I need to enter?
Enter Finished length, Finished width, Lengthwise shrinkage, Crosswise shrinkage. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Finished length (cm) moves the answer to Finished length (cm) 50 → Cut length (cm) 52.6 and Finished length (cm) 200 → Cut length (cm) 210.5. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
The lengthwise figure is usually the bigger one, because weaving and finishing hold the warp under tension; denim often splits 3–10% lengthwise against 1–2% across. Treat this as the fallback for fabric you genuinely cannot pre-wash, such as a knit that has to be cut as it comes off the roll. Washing before cutting removes the guesswork and is always more accurate. Some fabrics also keep shrinking into the second and third wash, so trusting a single wash test can leave the garment shorter again later.
Related calculators
Materials differ in density and absorption. If your label states a figure, use it — the defaults here are only common values.