Glove Size Calculator

Background.

A glove size calculator is the one apparel sizing tool with a real published table behind it. EN ISO 21420:2020, the general requirements standard for protective gloves, sizes gloves against a hand-sizing system keyed on two measurements — hand circumference and hand length, both in millimetres — across numeric sizes 4 to 13 with letter equivalents from 3XS to 4XL. That is not a retailer convention or an industry rule of thumb; it is a standard, and this page implements its table rather than approximating it.

The table has an elegant property that most size charts never mention. Every tabulated circumference is the size number in inches: 152 mm for a size 6 is 5.98 inches, 203 mm for a size 8 is 7.99 inches, 279 mm for a size 11 is 10.98 inches. Round each to the nearest whole number and you get the size back, at every one of the standard's ten rows. So the numeric glove size simply is your palm circumference in inches, and this calculator computes it that way — with a test asserting that the arithmetic reproduces all ten of the standard's own rows, so a future edit cannot silently drift away from the published table.

The second dimension is where a glove actually fails to fit. Hand length — wrist crease to the tip of the middle finger — sets the length of the finger box, and a hand that is broad for its length or long for its width will get two different answers from the two measurements. This page always reports both, and lets you choose which governs. The default is circumference, because that is the dimension most brands chart. For work gloves the safer choice is "both", which takes the larger of the two, on the reasoning that a palm can be a little roomy but a finger box that is too short cannot be stretched. When the two disagree the page says so, gives both numbers, and notes that a maker's long or short finger variant fixes the problem better than changing the size number does.

Two honest limits are worth stating before the result. First, the standard's length column is open-ended at both ends: sizes 4 and 5 are both published as "under 160 mm" and sizes 12 and 13 as "over 215 mm", with no distinct value. A hand length outside 160 to 215 mm therefore cannot be resolved to one size from length alone, and the page tells you that rather than guessing. Second, EN ISO 21420 governs protective gloves. Consumer gloves — driving gloves, winter gloves, gardening gloves — are not bound by it, and sports gloves are frequently sized on something else entirely. Boxing gloves are sold by weight in ounces, cycling and golf gloves often by their own letter charts, and none of those are what this table is for.

One thing this page deliberately does not report: a minimum glove length. That is a real requirement in some standards, and EN ISO 21420 does not impose one under its general requirements — it applies only where a specific use demands it, such as welding or firefighting gauntlets. If cuff coverage matters for your task, read the product's own declared length rather than inferring it from a size number.

Measure your dominant hand, since it is usually slightly larger, take the circumference at the knuckles with the thumb excluded, and keep the tape snug rather than tight. Those three details account for most of the disagreement between a calculated size and the glove that actually fits.

What is glove size calculator?

A glove size is a number from 4 to 13 describing a hand, and under EN ISO 21420:2020 it is defined against two body dimensions: hand circumference measured round the palm, and hand length measured from the wrist crease to the tip of the middle finger. ISO 8559-1:2017 is the companion authority for how those dimensions are located and taken on a body. The numeric scale is keyed to circumference in inches — size 8 is an eight-inch palm — and each number carries a published letter equivalent, from 3XS at size 4 to 4XL at size 13, with the familiar S, M and L falling at sizes 7, 8 and 9.

Unlike almost every other clothing size, this one is a standard rather than a convention, which is why a size 9 work glove from one European manufacturer is genuinely comparable to a size 9 from another. The standard covers protective gloves; it does not reach consumer or sports gloves, and it does not impose a minimum glove length except where a specific application requires one.

What the size cannot capture is hand shape. Two hands with the same palm circumference can differ by two sizes' worth of finger length, and that is the usual reason a nominally correct glove feels wrong — too tight across the fingertips or with slack at the ends. That is why this page reports the size implied by each dimension separately rather than collapsing them into one number and hoping.

How to use this calculator.

1. 01Pick your unit. The standard's own table is in millimetres, so millimetres are the default.
2. 02Measure your hand circumference: wrap the tape round the widest part of the palm at the knuckles, excluding the thumb, with the hand relaxed and flat. Snug, not tight.
3. 03Measure your hand length: from the wrist crease to the tip of the middle finger, hand flat and fingers together.
4. 04Use your dominant hand for both. It is usually slightly larger, and a glove that fits it will fit the other.
5. 05Choose which dimension should decide. Circumference is the usual basis and most brands' charts use it; "both" takes the larger of the two and is the safer choice for work gloves.
6. 06Read the size and the letter, then look at the two per-dimension figures underneath. If they disagree, your hand is broad for its length or long for its width.
7. 07If your hand length falls outside 160 to 215 mm, use the circumference — the standard's length column has no distinct value beyond those bounds and the page will tell you so.
8. 08For a specific glove, check the maker's own chart and any declared cuff length. This table covers protective gloves; consumer and sports gloves are sized on other systems.

The formula.

Both measurements are converted to millimetres first, because that is the unit EN ISO 21420's table is written in. The size from circumference is then the circumference in millimetres divided by 25.4 and rounded to the nearest whole number, half-up. That single line reproduces the standard's published table at every row: 101 mm returns 4, 127 returns 5, 152 returns 6, 178 returns 7, 203 returns 8, 229 returns 9, 254 returns 10, 279 returns 11, 304 returns 12 and 329 returns 13. A test asserts all ten, so the formula cannot drift from the table it claims to implement.

The size from hand length is a nearest-neighbour lookup against the standard's tabulated lengths — 160 mm for size 6, 171 for 7, 182 for 8, 192 for 9, 204 for 10 and 215 for 11 — with ties resolving upward to the larger glove, because being marginally roomy is a better failure than being short in the fingers. The midpoints are therefore 165.5, 176.5, 187, 198 and 209.5 mm, and each is tested at, below and above. Outside 160 to 215 mm the standard's own column is open-ended: sizes 4 and 5 share "under 160 mm" and sizes 12 and 13 share "over 215 mm", so the lookup returns the boundary size and the page states plainly that length alone cannot resolve it.

When the basis is "both", the reported size is the maximum of the two estimates. This is a deliberate asymmetry rather than an average: a palm circumference that is slightly generous leaves a glove a little loose across the back of the hand, which is tolerable, whereas a finger box that is too short is not wearable at all. Both per-dimension figures are always reported whichever basis governs, so the choice is visible rather than hidden.

Worked through with the page's own example: a hand measuring 21.5 cm round the palm and 19.5 cm long converts to 215 mm and 195 mm. From the circumference, 215 ÷ 25.4 = 8.46, which rounds to size 8. From the length, 195 mm is 3 mm from the tabulated 192 mm of a size 9 and 9 mm from the 204 mm of a size 10, so it resolves to size 9. The two dimensions disagree, and with the basis set to "both" the larger wins: size 9, letter L. The page reports both underlying figures and explains why the larger was taken.

A worked example.

Frequently asked questions.

References& sources.

1. [1]International Organization for Standardization / CEN, EN ISO 21420:2020 — Protective gloves — General requirements and test methods. Establishes glove sizes 4 to 13 against a hand-sizing system of hand circumference and hand length in millimetres, with letter equivalents 3XS to 4XL. Sold by ISO and CEN national members; the sizing table used here was read from a manufacturer's published reproduction of the standard's table, not from the standard itself.
2. [2]SATRA Technology, "The requirements of EN ISO 21420." Independent test-house summary confirming the 4–13 size range, that the two sizing criteria are hand circumference and hand length (wrist to the tip of the middle finger), and that minimum glove length is not specified under the general requirements but only where a specific use requires it.
3. [3]International Organization for Standardization, ISO 8559-1:2017 — Size designation of clothes, Part 1: Anthropometric definitions for body measurement. The authority for how hand girth and hand length are located and measured on a body. Sold by ISO; catalogue entry consulted.
4. [4]ISO 21420:2020 preview record hosted on the CEN/ISO national-mirror sample catalogue — used to confirm the standard's designation, edition year and title independently of the manufacturer reproduction above. The document is a locked PDF preview; the sizing table itself was not readable from it.