28 August 2026 · 7 min
How to read a thread count
A thread count is the whole specification of a plaid, written in a line. It is not a description of the cloth — it is the cloth, in the sense that two mills given the same count will weave the same thing. Once you can read one, most of the mystery goes.
Colour, then how many
K4 B24 K2 W6
Read it left to right, in pairs: a letter for the colour, a number for how many threads of it. Four black, twenty-four blue, two black, six white. The order is the order they are wound onto the loom, so the line is also a set of instructions.
The letters are a register shorthand, not a colour system — they say which colour, not which shade. The exact shade is set separately, which is why the same count can be woven in a dozen colourways and still be the same sett.
- K Black
- W White
- R Red
- B Blue
- G Green
- Y Yellow
- A Azure
- N Neutral grey
- P Purple
- T Brown
- O Orange
- C Charcoal
Prefixes work the way you would guess: LB light blue, DR dark red.
The half you write, and the whole it makes
Most tartan setts are reflective: the sequence runs to the end and turns back on itself, like a word read forwards then backwards. So the line above is only half the story.
The turn happens on the first and last stripes, not after them. Those two are the mirror axes, and an axis is crossed once, not twice — so they are counted once while everything between them appears twice:
K4 B24 K2 W6 K2 B24
36 threads written, 62 threads woven. If the pivots were doubled like the rest you would get 72, and the cloth would carry a black bar twice as wide as intended at every turn.
One line, two cloths
Not every plaid mirrors. A repeating sett runs the sequence end to end and starts again — common in madras and in shirting stripes. Same four counts, different cloth:
This is why a thread count on its own is incomplete. Without knowing which way it turns, you have the ingredients but not the recipe.
The pivot has to be halvable
A mirror axis sits in the middle of its stripe. Give that stripe an odd number of threads and the axis falls between two of them — there is no centre thread for the cloth to turn on. The designer says so rather than quietly rounding:
Pivot stripe K5 has an odd thread count; the mirror axis falls mid-thread.
It is a warning, not an error. Odd pivots are woven; they simply make the two halves differ by a thread, and that is worth knowing before a mill discovers it for you.
What a good count looks like
Short setts read as stripes rather than checks — under about eight threads there is nothing to see. Very long ones stop repeating within a garment. And the count interacts with the weave: a sett that does not divide the weave repeat doubles the size of the tile, which is a problem of its own.