Knit Stretch / Negative Ease
Measure fabric stretch and size knit patterns with negative ease.
A marked 10 in that is not being pulled.
How far the same span pulls comfortably.
The wearing-over measure, e.g. bust or hip.
60% stretch
High stretch.
- Suggested negative ease
- 10%
- Cut measurement
- 30.6 in
Cut the garment piece narrower than the body by the negative ease so the knit grips. For low-stretch knits add wearing ease instead, just as you would for a woven.
About This Tool
The Knit Stretch and Negative Ease calculator measures how far your knit pulls, then tells you how much narrower to cut the piece than the body so it hugs comfortably without suffocating.
You stretch a marked span of fabric, enter the relaxed and stretched lengths, and add the body measurement you are fitting.
It computes the stretch percentage, sorts the fabric into a stretch category, and suggests a negative ease with a cut measurement.
The answer replaces the coin-flip of cutting a knit tee the same size as your woven pattern and getting a tent or a straitjacket.
Whether you are sewing a fitted tee, a legging or a loose dress, one reading sets the right cut.
It also reminds you that a very low stretch knit should be treated almost like a woven.
Why Knit Stretch / Negative Ease Math Matters
Knits are drafted with negative ease, meaning the garment is smaller than the body and relies on stretch to fit.
Cutting a high-stretch knit at body measurement makes it sag and pool instead of springing back.
Cutting a low-stretch knit too small means it will not pull over the head or hold its shape.
The stretch percentage is the single number that decides how aggressive your negative ease can be.
Recovery matters too, because a knit that stretches but stays baggy will not keep a close fit all day.
Getting the cut size right on the first knit avoids a fitting shell that behaves nothing like the worn garment.
A measured stretch beats guessing, since two fabrics that feel similar can differ by dozens of percent.
The Formula
The stretch percentage equals the stretched length minus the relaxed length, divided by the relaxed length, times one hundred, and the cut measurement is the body measurement reduced by the suggested negative-ease percentage.
- Relaxed length —
- a marked span of the knit lying flat and undisturbed, often ten inches
- Stretched length —
- how far that same span pulls to before it fights back or reaches its limit
- Negative ease —
- the percentage the cut piece is made smaller than the body so the fabric grips
- Cut measurement —
- the body measurement reduced by the negative ease, giving the size to cut
The tool maps stretch into bands, from near-woven under 25 percent up to very high over 100, and pairs each with a sensible negative ease to start from.
Worked Example: Step by Step
- 1You mark ten inches on a jersey knit and gently stretch it to sixteen inches.
- 2You enter the relaxed ten and the stretched sixteen, and your bust measures 34 inches.
- 3The calculator finds a 60 percent stretch, placing the fabric in the high-stretch band.
- 4It suggests about 10 percent negative ease for that level of stretch.
- 5Your cut bust measurement therefore comes to roughly 30.6 inches, smaller than your body.
- 6You draft the tee to that number, sew it, and it skims the figure without clinging or bagging.
- 7Had the same knit pulled only to twelve inches, the tool would have kept the cut far closer to your body.
How to Use This Calculator
- Mark a flat, relaxed span on the knit and record that length.
- Stretch it to a comfortable limit and record the stretched length.
- Enter both so the calculator finds the stretch percentage.
- Add the body measurement you are fitting the garment to.
- Read the suggested negative ease and the cut measurement.
- Confirm the fit with a quick knit shell before cutting the good fabric.
Key Terms
- Negative ease
- making the garment smaller than the body so the stretch of the fabric pulls it into fit
- Stretch percentage
- how far a knit elongates past its relaxed length, expressed as a percent of that length
- Recovery
- a knit's ability to spring back to its relaxed shape after being stretched
- Relaxed length
- the undisturbed measurement of a marked span before any pulling
- Two-way stretch
- a knit that stretches mainly across the grain and less along it
- Wearing ease
- the positive room added to a woven or low-stretch garment for comfort and movement
Knit Stretch / Negative Ease Reference Table
| Stretch band | Percent range | Suggested ease |
|---|---|---|
| Low | under 25 | Treat near-woven, add ease |
| Medium | 25 to 50 | About 5 percent negative |
| High | 50 to 100 | About 10 percent negative |
| Very high | over 100 | About 15 percent negative |
Bands are a starting point, so always make a quick fitting shell, because two knits with the same stretch can recover very differently, and poor recovery means a close-cut piece still ends up baggy by the evening.
Common Mistakes & Pro Tips
- Sewing a knit to a woven pattern at full body measurement and getting a shapeless, sagging fit.
- Cutting a stiff low-stretch knit with heavy negative ease so it refuses to go over the head.
- Measuring stretch with a yank to the limit instead of the comfortable wearing stretch.
- Ignoring recovery, so a stretchy but lazy knit is cut too small and then grows baggy.
- Applying the same ease to a ribbing and a jersey when their stretch differs wildly.
- Cutting the good fabric before making a shell, then discovering the number was wrong.
Real-World Use Cases
- Drafting a fitted jersey tee that skims rather than clings.
- Sizing leggings from a very high-stretch lycra blend.
- Converting a favorite woven top pattern into a knit tee.
- Choosing ease between a stable interlock and a slinky rayon.
- Fitting a swim or dance suit on high-recovery fabric.
- Checking whether a thrifted knit is stretchy enough to use.
Knit Stretch / Negative Ease: Frequently Asked Questions
What is negative ease in plain terms?
It means cutting the garment smaller than your body and letting the fabric's stretch pull it in to fit. A fitted tee might measure a couple of inches less than your bust yet still feel comfortable once worn.
How do I measure my knit's stretch correctly?
Mark a flat, relaxed span, commonly ten inches, then stretch it only to a comfortable wearing pull and read the length. Yanking to the limit overstates stretch and leaves you cutting the piece too small.
Why does recovery matter as much as stretch?
A knit that stretches a lot but springs back keeps its fit, while one with poor recovery stays baggy however small you cut it. Two fabrics with identical stretch can wear differently because of recovery.
Should a low-stretch knit use negative ease?
Usually not. Under about 25 percent stretch the fabric behaves like a woven, so add positive wearing ease instead of cutting smaller than the body. Negative ease only pays off once there is real stretch to lean on.
Is the suggested cut the finished garment size?
It is a starting figure for the close-fit zone before seam allowances and style. Add or subtract for design ease and the fit you want, then verify on a cheap knit shell before the real fabric.
This page explains how the knit stretch / negative ease works, what each input means and where the numbers come from, so you can plan your next make with confidence.
Written by Bobbin & Form Editorial Team
Home sewists & machine-embroidery practitioners
Reviewed by Marie Delacroix
Custom sewist & machine-embroidery technician, 15 years at the machine
Formulas follow standard sewing and needlework references. Results are estimates — always confirm against your pattern and a pre-washed swatch.
Sources & further reading
- Threads Magazine — fabric cutting & yardage guides
- ISO 13934 — textile tensile & fabric property standards
- Your local fabric store's bolt-width charts