Sportswear Measurement Tolerances Explained: How Much Size Variation Is Normal?

Why Using the Same ±1 cm Tolerance Everywhere Is a Bad Idea

Different measurements have different effects on fit.

Being 1 cm out on the chest of a relaxed football jersey may have little noticeable effect. Being 1 cm out on a neck opening, cuff or small fitted panel can be much more significant.

For a conventional sports jersey, a discussion starting point might look something like this:

These numbers are examples, not an industry-wide standard. A loose football jersey, compression top, fleece tracksuit, cycling jersey and stretch legging should not automatically use the same tolerances.

A buyer and manufacturer should establish tolerances according to the actual product.

One of the Most Important Rules: Check Tolerance Against Your Size Grade

This is where poor specifications can create a problem even when the factory technically stays “within tolerance.”

Imagine your jersey specification contains:

The grade between sizes is 3 cm.

If you set the tolerance at ±1 cm, the possible production ranges become:

There is still a clear difference between sizes.

Now imagine giving the same garment a tolerance of ±2 cm:

You can now manufacture a 52 cm Small and a 51 cm Medium, and both garments technically pass the specification.

The sizes have crossed over.

Technical apparel guidance specifically warns against tolerances large enough to overlap adjacent graded sizes.

Mathematically, if adjacent sizes differ by a grade of G, and both use the same symmetrical tolerance T, preventing measurement overlap generally requires:

2T < G

For a 3 cm grade:

T < 1.5 cm

This simple check is extremely useful when reviewing a graded sportswear size specification.

A Measurement Without a Defined POM Is Not a Proper Specification

Writing:

Chest = 52 cm

is incomplete.

Where exactly should the inspector measure it?

At the bottom of the armhole?
One centimetre below it?
2.5 cm below it?
Between seam lines or outer edges?

A proper Point of Measurement defines the measurement type, location, starting point and ending point. Technical-design guidance recommends precisely defining these elements and ideally supporting them with diagrams.

For example:

P01 — Half Chest: Measure straight across from edge to edge, 2.5 cm below the armhole, garment laid flat and relaxed.

For sportswear, ambiguity becomes especially important with construction differences.

A set-in sleeve, for example, can be measured from the shoulder seam to the sleeve edge. A raglan sleeve does not have the same shoulder seam, so the specification may instead define sleeve length from the centre-back neck or another fixed reference point.

The measurement method must therefore follow the garment construction.

How the Garment Is Laid Down Also Matters

Stretch sportswear can produce different measurements depending on how the operator handles it.

A polyester-elastane jersey pulled slightly while being measured can easily produce a different number from the same jersey measured in a relaxed state.

The tech pack should therefore define the measurement condition.

For normal finished-garment measurements, the garment is commonly laid flat and relaxed without deliberately stretching the fabric. For elasticated areas, buyers may specify both a relaxed measurement and an extended measurement where appropriate.

For dispute-sensitive laboratory testing, conditioning becomes even more important. ASTM D1776/D1776M addresses textile conditioning because humidity and previous environmental exposure can affect textile testing results.

The important principle for buyers is consistency: the approved sample, factory and final inspector should be using the same measurement method and garment condition.

Sportswear Has Another Problem: The Garment Can Change Size After It Is Made

Production tolerance and dimensional stability are two different quality issues.

Suppose a jersey leaves production with a body length of exactly 72 cm.

After washing, it measures 70.5 cm.

The factory may have sewn the garment perfectly to specification, but the fabric or finishing process has produced dimensional change.

That is why serious apparel specifications should consider both:

finished-garment measurements and after-care dimensional stability.

ISO provides a useful framework for this type of testing. ISO 3759 covers preparation and measurement of garments for dimensional-change tests; ISO 6330 specifies standardized washing and drying procedures; and ISO 5077 provides a method for calculating dimensional change after those treatments.

AATCC TM135 also covers dimensional changes after standardized home laundering.

How to Calculate Garment Shrinkage

A simple dimensional-change calculation can be expressed as:

Dimensional Change (%) = (After Treatment − Before Treatment) ÷ Before Treatment × 100

For example:

Before wash body length = 72 cm

After wash body length = 70.6 cm

Therefore:

(70.6 − 72) ÷ 72 × 100 = −1.94%

The jersey has lost approximately 1.9% of its length under that test condition.

Width and length should normally be evaluated independently because fabrics do not necessarily shrink equally in both directions.

Research into knitted garments has also shown that dimensional change can be affected not only by fabric but by stitching parameters and washing conditions, which is why residual shrinkage needs to be considered during garment development rather than treated only as a fabric issue.

Why This Matters Even More for Stretch Sportswear

Polyester, polyester-elastane and other stretch knitted fabrics are common in performance sportswear. Our sportswear fabrics guide explains how fibre composition and fabric construction affect garment performance.

These materials can carry tension from knitting, dyeing, finishing, rolling and spreading. Their final dimensions depend partly on how those stresses are relaxed and stabilized.

Research on polyester/spandex knitted fabrics has demonstrated measurable changes in dimensional stability after repeated laundering under different washing conditions.

For this reason, buyers developing products such as compression shirts, cycling jerseys, leggings or fitted training wear should not approve the product based only on the first unwashed sample.

The fabric’s stretch, recovery and dimensional stability after the intended care treatment matter as well.

How Shrinkage Can Be Allowed for During Development

Suppose you want the finished jersey to measure:

72 cm body length after laundering

and development testing shows approximately:

2% length shrinkage

A simplified starting calculation would be:

Required pre-wash length = Final target ÷ (1 − shrinkage rate)

Therefore:

72 ÷ 0.98 = 73.47 cm

The pattern may need to produce something near 73.5 cm before treatment to achieve approximately 72 cm afterward.

This should not be used as an automatic pattern-making rule. Real production needs validation because stitching, fabric relaxation, finishing and garment geometry can influence the final result.

But it demonstrates why shrinkage data should reach the pattern and technical teams before bulk cutting, rather than being discovered during final inspection.

Measurement Tolerance and AQL Are Not the Same Thing

Another common sourcing mistake is confusing garment tolerance with AQL.

They answer different questions.

Measurement tolerance:
“Is this individual garment dimension acceptable?”

AQL sampling:
“Based on a sampled inspection, is this production lot acceptable?”

The current ISO 2859-1:2026 standard defines acceptance-sampling schemes indexed by Acceptance Quality Limit (AQL) for lot-by-lot inspection. It replaced the previous 1999 edition in January 2026.

Importantly, saying “AQL 2.5” does not simply mean 2.5% of your garments are allowed to be defective. AQL is an input used with the lot size, inspection plan, sample size and acceptance/rejection criteria.

If a garment measurement falls outside its agreed tolerance, the buyer’s inspection standard can classify that issue accordingly. Repeated out-of-tolerance measurements can then contribute to a lot failing the agreed inspection criteria.

The POM specification determines whether the measurement is wrong; the inspection plan determines what that means for the shipment.

A Better Sportswear Measurement Specification

Instead of sending a factory something like this:

send something closer to this:

The technical sketch should then mark P01, P02, P03 and the other measurement locations visually.

This gives the pattern maker, sample room, production line and QC inspector the same definition of the garment.

What an Out-of-Tolerance Result Can Tell You

Measurement inspection is useful for more than rejecting garments. The pattern of failures can help identify where a problem originated.

One outlier and an entire production run trending toward the edge of tolerance are not the same problem.

For example, imagine your chest specification is:

52 cm ±1 cm

A production sample measuring:

51.9, 52.1, 51.8, 52.2, 52.0 cm

is behaving very differently from:

51.1, 51.2, 51.0, 51.1, 51.2 cm

Both sets technically pass.

But the second group is sitting close to the lower specification limit and may indicate that the process is drifting away from the target.

Good quality control should therefore look not only at pass/fail results but also at consistency and production trends.

What Buyers Should Confirm Before Bulk Sportswear Production

Before approving bulk manufacturing, the buyer and manufacturer should have one controlled specification containing the approved size measurements, clearly defined POM methods, grading between sizes, tolerance for each POM, approved fabric and construction, measurement diagrams, and any required dimensional-stability or wash-testing criteria.

The final pre-production sample should be measured against that same document.

Most importantly, any revisions made during sampling should be transferred into the final production tech pack. Following a controlled sampling and manufacturing process helps prevent the sample room and production team from working from different versions.

Final Takeaway

Garment measurement tolerances are not simply an excuse for manufacturing variation.

Used properly, they form a quality-control system connecting the designer’s intended fit with pattern making, grading, sampling, cutting, sewing, laundering and final inspection.

For custom sportswear buyers, the most important principles are simple:

Define exactly where and how each measurement is taken, give each important POM an appropriate tolerance, ensure tolerances do not undermine your size grading, test dimensional stability when the fabric or product requires it, and make sure the approved sample and production team are working from the same final specification.

A well-prepared measurement specification reduces sampling rounds, makes inspections more objective and gives both the buyer and manufacturer a much clearer definition of acceptable bulk production.

Custom Sportswear Manufacturing With Byon Textile

Byon Textile works with brands, teams, clubs and businesses developing custom sportswear and apparel. Clear technical specifications during product development help turn an approved design into more consistent bulk production.

If you are planning a custom jersey, tracksuit, training kit or other sportswear project, contact Byon Textile to share your designs, size requirements and product specifications and discuss sampling and manufacturing.