You already know you are a medium in one brand and a large in another. That is not you being between sizes. It is that S, M and L are not units — no standard defines them, so every label picks its own.
Which is why every ZENITH product page carries a chart in centimetres. The letter is a name. The numbers are the actual garment.
The one thing that trips everyone up
Our charts list garment measurements laid flat, not body measurements.
So when the tank chart says a size S has a chest of 51 cm, that is the width across the garment from one underarm seam to the other, lying flat on a table. It is not the circumference of a chest. To compare it to your own chest measurement, double it: 51 cm flat is roughly a 102 cm garment circumference.
Get this wrong in the other direction and a perfectly good tank looks absurdly small on paper. It is the single most common sizing mistake, and it is entirely our industry's fault for never explaining it.
Read it against a garment you already own
The most reliable method needs no tape measure on your body at all.
- Find a top you already own that fits the way you want the new one to fit.
- Lay it flat, smooth out the wrinkles, and do not stretch it.
- Measure straight across from underarm seam to underarm seam. That is your chest number.
- Measure from the highest point of the shoulder straight down to the hem. That is your length.
- Match those two numbers to the chart, not to the letter on your old label.
If you fall between two sizes, decide with the length rather than the chest. Chest has ease built in; a hem that lands wrong is what you notice all day.
Worked example
Here is the performance tank chart:
| Size | Length (cm) | Chest, flat (cm) |
|---|---|---|
| S | 67 | 51 |
| M | 69 | 53 |
| L | 71 | 55 |
| XL | 73 | 57 |
| 2XL | 75 | 59 |
Two centimetres of chest and two of length per size. If your favourite tank measures 54 cm flat, you are between M and L on this garment — and the length is what should break the tie.
Do not carry a size between our products
This matters more than it sounds. Our tanks do not share a chart. The performance tank runs from 51 to 59 cm in the chest; the CRUX Ribbed Tank runs 43 to 51 cm, because a rib knit is designed to stretch onto the body rather than hang off it.
A size S in one is not a size S in the other. Check the chart on each product page — that is why it is on each product page rather than in one global sizing link.
About the tolerance line
Every chart ends with a note that 1–3 cm of variation may occur. That is not a disclaimer to cover ourselves. Cut fabric relaxes, and garments are made by people. Any brand publishing measurements to the millimetre is quoting a spec sheet, not a garment.
If the piece you receive is outside that range, that is a fault and we will replace it. Tell us.
Two measurements off a top you already own will get this right nearly every time — and it beats guessing a letter that was never a unit to begin with.