The rule: 2 hinges for doors up to 60″ tall, 3 hinges from 60″ to 90″, 4 hinges from 90″ to 120″ — add one hinge for every additional 30″. Heavy or solid-core doors may need an extra hinge or a heavier hinge regardless of height.
The height rule
| Door height | Hinges |
|---|---|
| Up to 60″ | 2 |
| 61″ – 90″ | 3 |
| 91″ – 120″ | 4 |
| Each +30″ | +1 |
Most standard 80″ interior and exterior doors fall in the 3-hinge band. The third hinge sits centered between the top and bottom hinges.
When to add a hinge
Heft and use matter, not just height. Add a hinge (or move up to heavy-weight ball-bearing hinges) for solid-core, solid-wood, or oversized doors, and for high-traffic commercial doors that cycle constantly. The extra hinge spreads the load and slows wear.
Why the count matters
Too few hinges concentrates weight, which strips screws, sags the door, and wears the top hinge out first. Getting the count right is the cheapest insurance against a binding door later.
Start with the height rule
The building-trade rule of thumb sizes hinge count by door height:
- Up to 60″: 2 hinges
- 60–90″: 3 hinges
- 90–120″: 4 hinges
- Each additional 30″: add one more
Then adjust for weight
Height sets the floor; weight is the real driver. Add one hinge beyond the rule for a solid-core, oversized, or exterior door, and use ball-bearing hinges once the door is heavy or high-traffic. Three hinges on a hollow interior door is overkill; two on a heavy exterior slab is asking for sag.
Why it matters
Every hinge you add divides the load. Too few, and each knuckle and its screws carry more than they should — the door sags, screws pull out of the jamb, and the top hinge fails first. Getting the count right up front is free; fixing a sagging heavy door later is not.
Frequently asked questions
Is 2 hinges ever enough for a full door?
Only for short or very light doors under 60″. Standard 80″ doors should have at least 3.
Do heavier doors always need more hinges?
Sometimes more, sometimes just heavier-rated hinges. A heavy 80″ door might keep 3 hinges but step up to heavy-weight ball-bearing models.