Light single jersey drapes close to the body.

It clings, it pulls, and it shows every millimeter you got wrong.

So a tee-size run has almost no margin for error.

Get the grade slightly off, and the small looks great, while the 2XL looks like a different garment.

This guide is the tee-specific version of that problem:

The parts that actually break on thin fabric and how we control them on our own floor.

We cut and sew tees in-house, so the numbers here aren’t pulled from a template.

They come from measuring thousands of finished bodies against spec and seeing where they drift.

Chapter 01

The key tee measurements:

Grading is just controlled change.

Before you can change a measurement across sizes, you have to know which measurements matter.

On a tee there are six that decide the whole fit.

These are your points of measure (POM).

Everything downstream, the grade, the size chart, and the fit comments reference them.

If your POM sheet is vague, your size run will be too. Full detail on how each point is taken lives in our measurement guide.

Chest:

The single most important number on a tee.

Measured flat, one inch below the armhole, straight across, seam to seam.

It’s a half measurement on one side of the laid-flat garment, so double it for the full circumference.

Chest sets whether the tee reads fitted, regular, or oversized, and it’s the measurement customers feel first.

Body length:

Taken from the high point of the shoulder (HPS) straight down to the hem.

Length controls the proportion of whether a tee sits at the hip, below it, or long.

On thin jersey, too much length makes light cloth pull and funnel.

Length and chest together define the silhouette.

Shoulder:

Measured seam to seam across the back.

This is where set-in and drop-shoulder tees split.

On a set-in tee the seam sits on the natural shoulder; on a drop-shoulder or oversized tee the seam falls onto the upper arm.

That difference changes how you grade a dropped seam, as it has to travel as sizes grow.

Sleeve length:

From the shoulder seam to the sleeve opening. Short sleeves seem forgiving; they aren’t.

On a boxy tee the sleeve reads as a proportion of the whole, so a sleeve that’s right on the medium looks stubby on the XL if it doesn’t grade with the body.

You also control the sleeve opening and bicep, both of which grade off the chest.

Neck:

Neck is a cluster, not one number: neck width, front neck drop, and back neck drop.

These decide whether the tee sits high and clean or open and relaxed.

Necks grade slowly; the human neck barely changes between a medium and an XL, so a big neck grade looks wrong fast.

Hem:

The hem or sweep is the width across the bottom, measured flat.

A hem narrower than the chest gives a taper; a hem equal to the chest gives a straight, boxy drop.

The chest-to-hem relationship is a design decision, so grade it deliberately.

From the floor:

We keep a laminated POM card at each cutting table. Every operator measures the same points the same way. Consistency at the table is worth more than precision on paper. For the exact measuring method tools, where to pin, and how to read a curved edge flat, see the garment measurement method.

Chapter 02

Grading rules for tees:

Grading is how one pattern becomes a full-size run.

You take a base size and apply a set of increments to the grade rules to step up and down to every other size.

Done right; every size looks like the same garment scaled.

Done wrong, only one or two sizes look like the sample.

Start with the theory:

This chapter is the tee-specific layer. If you’re still fuzzy on how grading works across all garments’ base sizes, grade rules, and the cost of grading, read pattern making & grading explained first. This page assumes it and goes straight at the tee.

Start from a base size:

Pick a base and perfect it first. Most tee makers use M or L.

Why the middle?

Because grading outward in both directions keeps error small, no size is more than a few grades from your proven fit.

And perfect the base fit on a real body in a fit session, before you grade anything. Grading a bad base just makes it fit in every size.

What is a grade rule?

A grade rule is the amount you add or subtract at each POM per size.

Think of it in two directions: the X-grade (width), how much wider each size gets across chest, hem, bicep, and shoulder; and the Y-grade (length), how much longer each size gets in body and sleeve.

Software does the geometry; your job is to set the right increments.

Typical starting increments:

These are common tee grade rules, a starting point to tune to your fit and market.

Values are per size; chest and hem are on the half (flat) measure.

Point of measure Typical grade / size Note
Chest (half) 1″ / 2.5 cm = 2″ full circumference
Body length 0.5-1″ sets proportion
Shoulder 0.25-0.5″ larger on drop-shoulder
Sleeve length 0.25-0.5″ grades with body
Neck width 0.125-0.25″ often held flat mid-run
Hem / sweep match chest or slightly less
Bicep opening 0.25-0.5″ grades off-chest

Uniform grade vs. proportional grade:

Two ways to grade, and the difference matters more on tees than almost anything.

A uniform (additive) grade adds the same inches at every size, which is simple and predictable.

A proportional (multiplicative) grade scales by a percentage, so bigger sizes gain more actual inches.

Uniform grading is fine for width alone.

But it quietly distorts proportion, because adding a fixed amount to a small garment changes its ratios more than adding the same amount to a large one.

On a fitted tee that’s ignorable. On a boxy tee it’s the whole ballgame.

Grade breaks:

Bodies don’t scale in a straight line.

A 3XL body gains width much faster than height, so a single rule from XS to 3XL makes the big sizes wrong.

The fix is a grade break: you change the increment partway up, commonly one grade for XS-XL and a larger width grade from 2XL up.

Set the break where your market’s bodies actually change shape: this is exactly where owning your fit data pays off.

From the floor:

We keep a graded nest every size stacked as overlapping pattern lines pinned up in the pattern room.

You can see the grade. When something’s off, it shows on the nest before it shows on a body.

Chapter 03

Keeping boxy and oversized consistent:

This is the hard part. It’s why this guide exists.

An oversized or boxy tee has a look wide relative to its length, short-ish, and square through the body.

A normal uniform grade destroys that look as sizes change: the small looks perfectly boxy, and the XL just looks big.

The ratio is the silhouette:

A boxy tee isn’t defined by its measurements. It’s defined by the relationship between their chest width and body length.

Say your base medium is chest 22″ flat, length 27″, a ratio of about 0.81. Now grade it uniformly at +1″ chest and +1″ length per size:

Size Chest (flat) Length Chest ÷ length
M (base) 22″ 27″ 0.81
XL (+2) 24″ 29″ 0.83
3XL (+4) 26″ 31″ 0.84

The ratio creeps.

Each size gets proportionally longer and narrower than the last, so the 3XL is measurably less boxy than the medium even though you graded it “correctly.”

On thin jersey, that drift is visible.

Hold the ratio, hold the look:

To keep a boxy tee box, the chest grade and length grade have to stay in proportion to the base ratio.

Two ways: proportional grading (scale width and length by the same percentage, so the ratio stays locked).

Or a tuned length grade (raise the length increment as sizes grow so length keeps pace with width).

Either way the principle is the same: decide the ratio you want, then grade to protect it.

We call this holding a ratio lock: pick the silhouette’s chest-to-length ratio at the base and refuse to let the grade move it.

Set the target once, then check it at every size.

If a size falls outside tolerance on the ratio, the grade is wrong, not the sample.

Target ratios by style are in the next chapter.

Drop shoulder is the other trap:

Boxy tees almost always use a dropped shoulder; the seam sits on the upper arm.

That seam has to move outward as the body grows.

Too small a shoulder grade and the seam creeps back toward the natural shoulder on bigger sizes; too large and it slides down the arm.

So shoulder and sleeve grade together, tied to the chest grade, the whole unit scales as one, or the armhole geometry warps.

Grading a hoodie instead? The hood, cuffs, and drop-shoulder change the rules to see hoodie grading.

The armhole ties it together:

As the shoulder drops and the body widens, the armhole depth (Y-grade) has to open up too, or the sleeve binds under the arm.

Armhole depth, chest, shoulder, and sleeve on an oversized tee these four move as a system.

From the floor:

We sew one silhouette-check sample at the top of every size run, the biggest size before bulk. Not the base.

The base always looks right; the extreme size is where a boxy grade fails.If the 3XL still reads boxy on a body, the whole run is safe.

Chapter 04

Length-to-width ratios by style:

Every tee style has a target proportion.

Grade to protect it, and every size in the run reads as the same style.

Here are the working ranges we build to chest-to-length relationships at the base size, i.e., your ratio-lock targets.

Fitted:

  • Look: close to the body, longer than it is wide, often slightly tapered at the hem.
  • Grade note: modest width grade; taper preserved across sizes. Tolerates a near-uniform grade because proportion drift is small.
  • Target ratio: fitted chest ÷ length at base

Regular / classic:

  • Look: straight through the body, sits at or just below the hip. The default tee.
  • Grade note: the forgiving one uniform grading holds up well.
  • Target ratio: regular chest ÷ length at base

Boxy / oversized:

  • Look: wide, square, relaxed. Shorter relative to width. Dropped shoulder.
  • Grade note: the demanding one needs proportional grading or a tuned length grade (Chapter 3). Use drop-shoulder construction; set-in fights the look.
  • Target ratio: boxy chest ÷ length at base

Cropped:

  • Look: short body, standard-to-wide chest. Hem at or above the waist.
  • Grade note: the length grade must be small and tightly controlled; a normal length grade makes a crop look uncropped by 2XL.
  • Target ratio: cropped length + chest ÷ length at base

The deeper breakdown of silhouettes, hem shapes, and how construction changes the drape lives in the silhouette guide.

The takeaway across all four: the style is the ratio. Grade the ratio, not just the inches.

Chapter 05

Fabric stretch and fit tolerance:

You can grade a perfect pattern and still get inconsistent fit because the fabric moves.

How much jersey stretches and how well it recovers changes what the garment measures on a body versus flat on a table.

On thin fabric the effect is amplified.

How the jersey behaves?

A single jersey stretches more across the width than the length, and when knitted in the round, it has natural mechanical stretch even with zero elastane.

Add elastane, and you get more stretch and, crucially, better recovery; the fabric springs back instead of staying stretched.

Recovery matters more than stretch: a fabric that stretches and stays stretched bags out and loses the fit you graded.

Weight matters too. A heavier jersey holds a boxy shape and hides small errors; a lighter jersey drapes closer and shows everything.

That’s why thin tees are the hardest to fit. Full fabric-and-weight detail is in the jersey guide.

Ease and negative ease:

Ease is the difference between body and garment measurement.

Positive ease means the garment is bigger than the body; every boxy fit lives here.

Negative ease means the garment is smaller and stretches to fit how a snug-fitted tee works.

You can only design negative ease if the fabric stretches and recovers; try it on a low-stretch cotton, and the tee won’t go on or blows out at the seams.

So decide the fabric first, then set the ease, then grade.

Fit tolerance on thin fabric:

Every point of measure gets a tolerance, the ± range that still passes QC, and the full method for setting it, including the rule that keeps it below half your grade, lives in our measurement tolerance guide.

Two things are tee-specific.

First, tighten the band on a thin jersey: an error that hides on heavy fleece shows on a clingy tee, so hold chest, length, and neck tighter than you would on a hoodie.

Second, keep the grade between sizes comfortably bigger than the combined tolerance.

If it isn’t, a passing “medium” and a passing “large” can measure the same, and your size run blurs together.

From the floor:

We relax-test every new fabric before finalizing the spec. Cut a marked panel, let it rest 24 hours off the roll, and re-measure.

Jersey shrinks back off the roll tension. Spec to the stretched, on-roll dimension, and every finished tee comes up small.

Chapter 06

Shrinkage as a fit factor:

Shrinkage is a fit problem disguised as a laundry problem.

A tee that fits out of the box and comes up two sizes short after one wash was never fitted right.

Shrinkage has to be built into the pattern, not discovered by the customer, and on thin cotton jersey it shows more, because there’s less fabric to absorb the change.

Finished spec vs. cut spec:

Two different specs.

Finished spec is what the tee measures after washing what the customer experiences.

Cut spec is what you cut and sew before washing, with shrinkage added on top.

You design to the finished spec and cut to the cut spec; the gap is your shrinkage allowance.

If shrinkage is 5% in length and you want a 28″ finished length, cut to about 29.5″. Cut to 28″, and the customer gets a 26.6″ tee.

Measure your shrinkage; don’t assume it:

  • Cut a panel of the actual production fabric.
  • Mark a precise measured square length and width for both.
  • Wash and dry it the way the customer will.
  • Re-measure the marks and calculate shrinkage % separately for length and width.

Length and width shrink at different rates; usually length more on tubular jersey, so carry two numbers:

Repeat for every fabric and every color finished differently. Finishing changes shrinkage.

Compacted / pre-shrunk fabric:

You can buy the problem down.

Compacted jersey is pre-shrunk at the mill, so residual shrinkage is low and stable.

It costs more per kilo but makes fit predictable and cuts your allowance for less fabric per garment, with fewer size complaints.

Shrinkage interacts with the grade:

Apply your allowance before you grade.

A percentage takes a bigger absolute bite out of larger sizes, so fold shrinkage into the pattern at the base, then grade the shrinkage-adjusted block.

Grade first and bolt shrinkage afterward, and your big sizes drift. The full testing method and wash protocols are in the shrinkage guide.

From the floor:

Every fabric batch gets a shrinkage docket before it’s cut for bulk. No docket, no cut.

One batch behaving differently from the last is exactly how a “perfect fit” tee goes wrong in production.

Chapter 07

Reading and correcting fit samples:

A fit sample is where the pattern meets reality.

The full fit-session process, which belongs in the room, choosing a fit model, and locking the base before bulk is its own guide:

See fit sessions and fit models. This chapter is narrower on what to look for on a tee sample, where thin jerseys behave differently from anything heavier.

Measure flat against the POM sheet first:

Before the tee goes on a body, lay it flat and measure every POM against spec and tolerance.

Mark each point in tolerance, out of tolerance, or trending near the edge.

A tee that measures out of spec flat will never fit right on a body; fix the spec deviation before you judge the fit.

What thin jersey shows on the body?

On a fit model matched to your base size, watch for the telltale light jersey that exposes that heavier cloth hides:

Where it clings across the chest or stomach, whether the hem sits level or dips front-to-back, whether the shoulder seam holds its intended position, and critically whether the fabric recovers after the model moves or stays pulled out of shape.

Thin fabric is unforgiving here. That’s the reason to fit on the real production weight, never a heavier stand-in.

Write feedback in numbers, not adjectives?

Turn every observation into a correction tied to a POM.

Not “the body’s too wide and it looks long” but “reduce chest 0.75″, reduce length 0.5″ from hem, shoulder 0.25” wide, bring to spec, neck drop good, hold.

“Separate spec corrections (bring the sample to a number you already set) from spec changes (you’re moving the target because the fit taught you something), or you’ll chase your own tail.

Correct once, then resample the extreme:

Apply corrections to the base, re-grade, and then sample the top of the run again, not just the base.

The base always looks right; the extreme size is where a boxy grade and your corrections either hold or fall apart, exactly as in Chapter 3.

Chapter 08

Building a size chart for your market:

Now you turn a proven, graded fit into the chart your customer reads.

A size chart isn’t a formality; it’s a fit promise.

Get it right and return drop, reviews improve, and the run you graded so carefully reaches people in the right size.

Body vs. garment measurements:

Two kinds of chart. A body measurement chart, “if your chest is X, buy M,” helps people find their size.

A garment measurement chart “M measures 22″ chest flat” tells people exactly what they’re getting. Publish both if you can.

Garment measurements kill ambiguity because a customer can measure a tee they already own, and they’re essential for oversized fits, where “M” means nothing when the garment is intentionally huge.

Design in the ease:

The gap between the two charts is your ease to publish it deliberately.

If the tee is oversized, say “designed with a relaxed fit; size down for a regular fit.”

If it’s a fitted negative-ease tee, say it’s meant to be snug and stretches to fit.

Silence here is where sizing complaints come from.

Match the chart to your market’s bodies:

Body sizing isn’t universal; a US medium, an EU medium, and an Asian medium can be different bodies.

If you sell to one market, chart to it; if you sell to several, publish region-specific charts or lead with garment measurements, which are objective and region-proof.

Anchor the chart to real bodies, ideally validated on fit models who represent the people actually buying.

The public-facing version of this chart, the live one your customers actually read, is your size guide. This chapter is how to build the graded spec that sits behind it.

Publish-it-clean checklist:

  • Flat-lay diagram showing exactly where chest and length are measured.
  • Both units inches and centimeters.
  • Garment measurements at minimum; body measurements too if you have them.
  • A one-line fit descriptor per style (oversized / regular / fitted).
  • Tolerance stated honestly finished garments vary slightly.
  • Placed on the product page, not buried in a policy.

Bringing it together:

A tee-size run that stays true on thin fabric isn’t luck. It’s a chain, and every link has to hold. Lock your six measurements.

Grade from a proven base with rules that fit your bodies, and break the grade where real bodies change shape.

Protect the ratio so a boxy tee stays boxy at every size.

Respect what the fabric does. Build shrinkage into the pattern, tested, not guessed.

Read fit samples with numbers, not adjectives. Then turn all of it into a size chart that describes your customer.

Thin jersey punishes shortcuts, but that’s the opportunity.

Most brands get the tee fit slightly wrong, and slightly wrong is visible on a tee.

Get it right across the whole run, and you own a difference people feel every time they put it on.

Common fit & grading questions

Grade from a middle base size, usually M or L, and step outward in both directions.

Basing in the middle keeps the error small; no size is more than a few grades from your proven fit.

Perfect the base fit on a real body before grading anything.

A uniform grade adds fixed inches to every size, which quietly changes the chest-to-length ratio as sizes grow.

The silhouette is that ratio, so it drifts, and the biggest sizes read less boxy.

Hold the look by grading width and length proportionally, or by tuning the length grade up on larger sizes.

Cotton jersey shrinks usually more in length than width, and the amount depends on the fabric and finish.

Never assume a number:

Cut and wash a marked panel the way the customer will, measure length and width shrinkage separately, and build that allowance into the cut spec so the tee lands on the finished spec after washing.

Publish both if you can. Body measurements help customers choose; garment measurements, especially a flat chest and length, remove ambiguity because a customer can measure a tee they already own.

Garment measurements are essential for oversized and boxy fits, where the size label alone tells the customer nothing.

Set tolerance per point of measure, not one number for the whole garment.

Tighten it on the chest, length, and neck; loosen it elsewhere; tighten further on thin fabric.

Always keep the grade between sizes comfortably larger than the tolerance band, or two adjacent sizes can overlap.

From the T-shirt manual

This is one chapter of The Complete T-Shirt Manufacturing Guides:

These chapters cover taking a T-shirt brand from idea to shipped units, costing, sourcing, tech packs, QC, freight, and launch comparisons. All written from the Sialkot factory floor of Gibben Clothing.

Open The Full T-Shirt Guides

On the floor · Sialkot

Written by

Faizan Ahmad

Chief Apparel Technologist & Head of Manufacturing, Gibben Clothing · Sialkot, Pakistan

Faizan leads production at Gibben Clothing, a cut-and-sew streetwear manufacturer in Sialkot, with 8+ years turning raw yarn into retail-ready hoodies, tees, bottoms, jackets, tracksuits, and headwear. He doesn’t just write about clothing; he works the floor, so every guide here is grounded in real fabric behavior, QC standards, and production data from live runs.