Where should door hinges be positioned?

Standard hinge positions are 225mm from the top of the door to the top of the upper hinge, and 225mm from the bottom of the door to the bottom of the lower hinge. A third (centre) hinge, if used, goes midway between the two. Fire doors must have 3 hinges. Some carpenters use 150mm for the top and 225mm for the bottom.

What is the correct latch height for a door?

The standard latch (handle) height is 990-1050mm from the finished floor to the centre of the latch. Most handles are set at 1000mm. For accessibility (Part M), handles should be 900-1050mm high and operable with one hand. Lock/deadbolt mechanisms are typically fitted above or below the handle.

What margins should I leave around a hung door?

Standard margins are 2-3mm on the hinge side, 2-3mm on the latch side, and 2-3mm at the top. The bottom gap should be 8-10mm for carpet clearance (or 3-5mm for hard floors). Fire doors require a maximum 3mm gap at the top and sides (with intumescent strip) and a maximum 8mm gap at the bottom (or 3mm with threshold seal).

What hardware is required for fire doors?

FD30/FD60 fire doors require: 3 CE-marked fire-rated hinges, intumescent strip around the full perimeter (top and sides), cold smoke seal, self-closing device (overhead closer or concealed closer), fire-rated lock/latch, and no letter plates unless fire-rated. All hardware must be CE marked and suitable for the fire rating.

How many hinges does a door need?

Standard internal doors need 2 hinges (75mm or 100mm butt hinges). Heavy doors, doors over 2040mm tall, and all fire doors need 3 hinges. External doors typically need 3 hinges due to their weight. The third hinge prevents the door from warping and distributes the weight more evenly.

TradeCalculator

Door Hanging Calculator

Calculate hinge positions, latch height, margins and fire door hardware requirements. UK Building Regulations compliant.

Door Width

Standard: 762mm (2'6") or 838mm (2'9")

Door Height

Standard: 1981mm (6'6")

Door Type

Fire doors require extra hardware

Hinge Type

Fire doors need CE-marked hinges

Number of Doors

For bulk quantities

Fire door specification

3 hinges, intumescent strip, self-closer

Price Per Hinge (optional)

Price Per Latch (optional)

How We Calculate This

This calculator determines hinge positions, latch height, clearance margins and fire door hardware requirements based on door type and dimensions.

The formula

Top hinge: 225mm from door top
Bottom hinge: 225mm from door bottom
Centre hinge: midway (for 3-hinge doors)
Latch: 990-1050mm from floor

Door margins

Standard: 2-3mm top and sides, 8-10mm bottom
Fire doors: max 3mm top/sides, max 8mm bottom
Fire doors require intumescent strip in the gap
Always check door is square before fitting

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.