Label stock
99.1 × 38.1 mm labels
Two columns, seven rows, and a shape that came from envelopes. It turns out to be the right shape for shelves.
An address label doing a different job
99.1 × 38.1 mm exists because a posted envelope needs a block of four or five lines about a hundred millimetres wide. Two columns of 99.1 mm plus margins fills A4's width; seven rows of 38.1 mm is 266.7 mm, which fits 297 mm comfortably. Fourteen to a page.
Almost nothing in a laboratory is shaped like an envelope, so the size looks wrong for lab work until you stop thinking about vessels. Shelves, drawers, freezer racks, equipment panels and box fronts are all long and shallow, and all read from a metre or more away. A label that is 99 mm wide can set an identifier at 14 pt and still have room underneath for the detail.
What this size is
- In inches
- 3.9 × 1.5 in. Only the height came from inches. The width is what a sheet of paper divides into, which is why the two numbers look unrelated.
- Vessels it wraps
- A GL45 reagent bottle and nothing smaller. Its usable band is about 200 × 90 mm, which this label fits inside.
- Die-cut sheets
- A4 · 14-up · 99.1 × 38.1 mm — 14 per A4 sheet.
- Roll stock that carries it
- 101.6 mm. The narrowest that takes it is 101.6 mm, and a roll narrower than the label is reported as an error rather than trimmed.
What fits on a 99.1 × 38.1 mm label
| Type size | Lines | Plex Sans | Barlow Condensed | Atkinson Hyperlegible | Plex Mono | Space Mono | Courier Prime |
|---|---|---|---|---|---|---|---|
| 4.5 pt | 19 | 127 | 175 | 128 | 101 | 99 | 102 |
| 5 pt | 17 | 114 | 158 | 115 | 91 | 89 | 91 |
| 6 pt | 14 | 95 | 131 | 96 | 76 | 74 | 76 |
| 7 pt | 12 | 82 | 113 | 82 | 65 | 64 | 65 |
| 8 pt | 10 | 71 | 98 | 72 | 57 | 56 | 57 |
| 10 pt | 8 | 57 | 79 | 57 | 45 | 44 | 45 |
Wide labels need shorter lines, not longer ones
Ninety-five characters is roughly twice the line length that reading research treats as comfortable. A block of text set across the full width of this label is genuinely harder to read than the same text on a narrower one, because the eye loses its place returning to the start of the next line.
The fix is to use the width for size rather than for length. Set the identifier large enough to be read across the room, and keep supporting lines to half the label's width in a column, leaving the other half empty or carrying a code. A label read at two metres has one job, and everything that competes with that job is making it worse.
This is also the stock to reach for when a label has to be read by someone who is not looking for it — a hazard notice on a freezer door, a contents summary on a rack. Those are found rather than consulted, and finding depends entirely on the largest thing on the label.
Common questions
- Why 99.1 mm rather than 100 mm?
- Two columns of 100 mm would be 200 mm, leaving only 5 mm each side of A4 — inside the unprintable margin of most office printers. Dropping each column by 0.9 mm buys nearly two millimetres of margin across the page, which is the difference between a sheet that feeds reliably and one that clips.
- Can I use it for equipment and calibration labels?
- It is a good shape for them. Equipment labels carry an asset number, a date and an initial, all of which want to be read without crouching. Consider a polyester face for anything that will be wiped down, and remember that a calibration label's job is to be legible at the end of its interval, not the day it goes on.
Open it in the editor
The editor loads at 99.1 × 38.1 mm with a worked example in place. It runs entirely in your browser: nothing you type is uploaded, and there is no account to make.
Last reviewed 2026-09-13.