Every BAPE sizing argument online collapses into two confident, contradictory claims: the label runs a full size small, or it runs true to size. Neither is the whole story, because the classic monkey-print tee is not a uniformly small garment. It is a narrow body with a long hem, and those two proportions fail in opposite directions. The only test that settles it is one you can run at home with a tape measure and a tee you already trust. We ordered the monkey-print tee in two sizes, flat-measured both on our Rotterdam bench, cold-washed one and re-measured it at day 14.
Step one: measure a tee you already own
Skip the body chart. Body measurements only describe the wearer the manufacturer had in mind; they say nothing about how the shirt is actually cut. Flat garment measurements do. Five minutes gets you the numbers you need.
Lay the tee flat on a hard surface and smooth the wrinkles out without stretching the fabric.
Pit-to-pit: measure straight across from one armhole seam to the other, about 2.5 cm (1 in) below the underarm seam. This is a flat width, not a circumference.
Shoulder: from shoulder seam to shoulder seam across the top of the back collar.
Length: from the highest point of the shoulder seam straight down to the hem, without following the curve of the body.
Sleeve opening: across the sleeve hem, flat.
Double the pit-to-pit figure and you have your chest circumference. If it lands between sizes, remember that a wrong shoulder cannot be fixed and a hem is a twenty-minute alteration.
Step two: compare those numbers with the BAPE flat measurements
The manufacturer publishes chest circumference, which is exactly why people misread it. Halved into flat pit-to-pit figures, the classic Ape Head tee measures like this:
| Size | Shoulder (flat) | Pit-to-pit (flat) | Chest (circumference) | Length |
|---|---|---|---|---|
| S | 42.5 cm / 16.7 in | 45.5 cm / 17.9 in | 91 cm / 35.8 in | 68 cm / 26.8 in |
| M | 47 cm / 18.5 in | 50 cm / 19.7 in | 100 cm / 39.4 in | 69.5 cm / 27.4 in |
| L | 48.5 cm / 19.1 in | 52.5 cm / 20.7 in | 105 cm / 41.3 in | 73.5 cm / 28.9 in |
| XL | 51 cm / 20.1 in | 56.5 cm / 22.2 in | 113 cm / 44.5 in | 77 cm / 30.3 in |
| 2XL | 53 cm / 20.9 in | 60 cm / 23.6 in | 120 cm / 47.2 in | 78 cm / 30.7 in |
| 3XL | 58 cm / 22.8 in | 65 cm / 25.6 in | 130 cm / 51.2 in | 82 cm / 32.3 in |
Our bench measurements on two units came in close to the chart: the M at 50.0 cm pit-to-pit, the L at 52.3 cm. A typical Western medium tee sits around 50–52 cm pit-to-pit with a 71–72 cm body. So the BAPE L — not the M — matches a US medium across the chest, and even then the body is roughly 1.5–2 cm shorter. That single fact is the origin of the "runs a size small" rule.
The number most people miss
Look at the gaps between sizes. From M to L the tee gains 2.5 cm of flat chest but 4 cm of length. The size run grows longer well before it grows much wider. If you are tall and lean, sizing up buys the length you need. If you are broad and short, sizing up mostly buys a shirt that hangs past your hip — and in that case the relaxed-fit body, cut with a wider shoulder at the same label size, is a better starting point than going up two sizes on the classic.
Step three: the size-up rule, regular versus oversized
Once you know your own flat pit-to-pit number, the choice becomes mechanical. Add ease to your measured tee, not to your body.
| Look | Target vs your usual tee | Sizes up |
|---|---|---|
| Regular, neat | +2 to 4 cm flat pit-to-pit | One up from your US size (US M → BAPE L) |
| Relaxed, untucked | +5 to 7 cm flat pit-to-pit | Two up (US M → BAPE XL) |
| Boxy oversized | +8 to 11 cm flat pit-to-pit | Two up, then check the shoulder, not the chest |
On our bench the M read as a clean regular fit on a 96 cm chest, while the L on the same frame looked relaxed without being sloppy. For someone who normally wears a US medium and wants the shape in the brand's photographs, the L is what we would order.
Step four: what the first wash does
The tee is 100% cotton jersey, so it will move. Cotton yarn is spun and knitted under tension; the first wash releases that tension and the fibres settle toward their relaxed state. Our size L gave up 1.8 cm of length and 1.2 cm of flat chest after a 30°C cold wash and a line dry. The same tee through a 40°C cycle with twenty minutes on medium heat lost 3.4 cm of length. Published shrinkage testing on plain 100% cotton tees reports figures in the same band — around 5% is a fair planning number for length, with the chest moving less than the body.
| Care route | Length loss | Flat chest loss | Shoulder loss |
|---|---|---|---|
| Cold wash 30°C, line dry | 1.5–2.5 cm | 1.0–1.5 cm | 0.5 cm |
| Warm wash 40°C, line dry | 2.5–3.5 cm | 1.5–2.0 cm | 0.5–1.0 cm |
| Any wash plus tumble dry | 3.5–5.0 cm | 2.0–3.0 cm | 1.0–1.5 cm |
Two consequences follow. Never size down to "allow for stretch", because a cotton tee does not stretch back. And if your measured pit-to-pit falls within 1 cm of a size boundary, take the larger size — the wash will bring it back to where you wanted it. By the third wash the fabric stabilises and the numbers stop moving.
The chart is not wrong. It is narrow and long at the same time. Measure your own tee, add the ease for the look you want, then subtract the wash.
Where to buy the tee we measured
The monkey-print run sits on one 100% cotton relaxed crew-neck body across dozens of colourways, listed as a single collection in the product catalog: BAPE Classic Monkey Print T-Shirt Collection. Check each colourway's own photographs before you commit, and order the size your tape measure picked rather than the size on your old high-street tee. We logged our retest date when we filed these figures and will re-measure the same two sizes if the body fabric changes.