Hinge Grades and Hinge Count 2026: EN 1935 Grades 1–14, ANSI/BHMA A156.1, and How Many a Door Needs

A hinge specification that says "stainless butt hinge, 4 inch" has named a size and a material and left out both of the things that determine whether the door still hangs straight in five years. The two that matter are the grade and the count.

THE EN 1935 LADDER

EN 1935 is the European standard for single-axis hinges. It classifies a hinge across eight digits, and the one that gets quoted is the grade: 1 to 14, ascending, each tied to a maximum tested door mass when the hinge is used in the tested configuration.

The lower grades cover light internal doors. The middle of the ladder covers normal commercial internal and entrance doors. The upper grades cover heavy doors, including the mass ranges where a fire door or a security door lands.

The number that gets misread is the mass. An EN 1935 grade states the door mass the hinge was tested to carry in a specific configuration, normally a set of three on a door of stated height. It is not a per-hinge load rating you can divide or multiply at will, and it is not a figure you can extrapolate by adding a fourth hinge.

Alongside the grade, the classification carries a category of use, a durability figure in cycles, a door mass, a fire rating suitability, a safety class, a corrosion resistance grade and a security grade. A specification that quotes only the grade digit has quoted one of eight.

THE ANSI/BHMA A156.1 APPROACH

A156.1 covers butts and hinges and classifies them by weight class and by frequency of use rather than by a single ascending grade number. The practical shape of it is a matrix: a standard-weight or heavy-weight hinge, in a high-frequency or low-frequency application, in a stated size.

The consequence for cross-market work is the same one that appears with door closers. An EN grade is a single value a supplier can match. A North American classification is a combination. A schedule written for both markets should state the door's mass, its height, its expected daily cycles and whether it is a fire door, and let each market's supplier map that onto its own classification.

HOW MANY HINGES A DOOR NEEDS

The count is governed by leaf height first and leaf mass second, and the convention is well settled.

That is the height rule. The mass rule runs alongside it: if the door's mass exceeds what the chosen grade covers at the count the height rule gives, the answer is a higher grade, not an extra hinge.

WHY AN EXTRA HINGE IS NOT A HIGHER GRADE

This is the error worth naming, because it is made by people who are being careful rather than careless. A door is too heavy for the hinges specified, so a fourth hinge is added to share the load.

It does not work the way the intuition suggests. The load on a hanging door is not distributed evenly across the hinges; the top hinge carries the largest share of the pull-out force because the door's weight acts as a lever about the bottom of the jamb. Adding a middle hinge adds support at the point where the least force is present. The top hinge is still the one that will fail, and it is still under-specified.

A middle hinge does do real work — it resists the leaf warping and it stiffens a tall door — but it is not a substitute for a grade that covers the mass.

THE THREE FAILURE MODES

Screw pull-out at the top hinge. The hinge itself is intact, the frame has given way. This is the signature of a hinge or a fixing under-specified for the mass, and it is the one that makes a door drop and bind against the strike.

Knuckle wear. The pin and knuckle work loose over cycles, and the door develops play — it rattles, and the latch stops meeting the strike squarely. This is the signature of a durability class below the door's actual traffic, and it is why the cycle figure in the classification matters as much as the mass.

Corrosion at the pin. On an external door or a coastal site, a hinge whose corrosion grade is below its exposure seizes or bleeds rust down the frame. The grade for this is a separate digit in the EN 1935 classification, and specifying a high load grade does nothing for it.

BEARINGS, AND WHERE THEY EARN THEIR COST

A plain-knuckle hinge runs metal on metal. A ball-bearing or washer hinge places a bearing between the knuckles, which reduces friction and wear at the cost of a slightly thicker knuckle stack.

The place a bearing hinge earns its price is the combination of a heavy door and high traffic — a main entrance, a stair door on a busy route, anything with a closer fitted, because a closer cycles the door whether or not anyone uses it gently. On a light internal door at low traffic, a plain hinge is the correct specification, not a cheaper one.

FIRE DOORS

A hinge on a fire door has to be suitable for that use, and suitability is not a property of the material. Steel and stainless are common on fire doors and brass generally is not, but the decision is made by the fire test of the whole assembly, not by the melting point of the hinge.

The practical rule: a fire door's hinges are part of its tested assembly. Substituting a hinge of the same size and a different classification is a change to the assembly, and the certificate covers what was tested.

WHAT WE PUBLISH

Our hinge pages carry the leaf dimensions, thickness, material and finish as we measure and supply them, with imperial equivalents on the English pages. Where a model has been tested to an EN 1935 grade or an A156.1 classification, that is stated. Where it has not, no grade appears — a hinge grade is a test result, and a test result is either held or it is not.