Garage door opener size selector
What horsepower opener does the door need? Enter the size and construction (or a known weight) and get the HP / DC class to spec, with belt-vs-chain guidance. Instant, no signup.
Opener horsepower by door weight
Horsepower classes are about reserve and lifespan, not speed. A door that's balanced well barely loads the motor, but sizing up gives headroom for cold weather, stiff rollers, and years of cycles.
| Door weight | Opener | Typical use |
|---|---|---|
Under ~150 lb | 1/2 HP | Single / lighter 2-layer steel doors |
~150–250 lb | 3/4 HP | Most double & insulated doors (the workhorse) |
~250–350 lb | 1 HP | Heavy insulated, wood, or larger doors |
Over ~350 lb | 1.25 HP+ / jackshaft | Very heavy or oversized, or go wall-mount |
HP vs DC vs newtons
Older openers list true AC horsepower. Most new units use DC motors rated by a "comparable HP" or a force figure in newtons (e.g. ~800N ≈ 3/4 HP class). Match or beat the HP class above, and prefer soft-start/soft-stop for a heavy door; it's gentler on the door and quieter.
Belt, chain, or wall-mount
- Belt drive: quietest rail drive; best over living space.
- Chain drive: lowest cost, a little louder; fine for a detached garage.
- Wall-mount (jackshaft): mounts beside the torsion shaft, near-silent, frees the ceiling; great for tall/heavy doors and tight headroom.
Want the full walkthrough, not just the tool? Read the field guide: What size garage door opener do you need? HP by door weight, not vibes
Frequently asked questions
What size opener do I need for a double garage door?
Most double (16×7) insulated steel doors are well matched to a 3/4 HP opener (or the DC equivalent). Lighter single doors are fine on 1/2 HP; heavy wood, full-view glass, or oversized doors move up to 1 HP or a wall-mount jackshaft.
Is 1/2 HP or 3/4 HP better?
1/2 HP handles most single and lighter doors and costs less; 3/4 HP is the workhorse for double and insulated doors, running with more reserve and less strain, which usually means a longer life. When in doubt on a double door, size up.
What about DC openers and newtons?
Modern DC-motor openers are often rated by "comparable HP" or by force in newtons rather than true horsepower. Match or exceed the HP class the calculator suggests, and favor a soft-start/soft-stop DC unit for a heavy door.
Belt or chain drive?
Belt drives are quieter, the right call for an opener over a bedroom or a living space. Chain drives cost less and are fine for a detached garage. Screw drives sit in between. Wall-mount (jackshaft) openers are quietest and free the ceiling.
Audrey does this in the truck, hands-free.
This calculator runs the exact logic built into Ask Audrey, where your techs just ask out loud and get the answer cited to your own manuals (and estimate the door weight first). Every tech, a senior tech.