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Garage door cable length calculator

Lift cable length comes from the shaft height and the drum. Use it to read a quote; the replacement itself is technician work.

Shaft + drum sets the lift cable length Floor to shaft center plus the drum allowance; subtract high lift, or door height for vertical lift (Service Spring method).

This garage door cable length calculator follows the method a spring maker publishes: measure from the floor to the center of the torsion shaft, then add the allowance for your drum.

High-lift tracks subtract the high-lift amount, and vertical-lift tracks subtract the door height. The allowance depends on the drum model, so type it from the drum maker’s chart.

Shaft height, then the drum

Nothing is emailed. The drum allowance is not preset.

Measured with the door closed. Do not touch the springs.

From the drum maker’s chart for your drum. Starts empty.

High lift only. 0 otherwise.

Vertical lift only.

— Cable length
— In feet
— Safety

What this assumed —

Cables are never DIY. HyreGarage does not repair doors.

How is garage door cable length worked out?

From the height of the torsion shaft, plus an allowance set by the drum. High-lift and vertical-lift tracks subtract from that.

Service Spring, a spring maker, publishes the method. For a standard lift: measure from the floor to the center of the shaft, then add the allowance for your drum. For high lift, subtract the amount of high lift. For vertical lift, subtract the door height.

The allowance is not one number. It depends on the cable drum model and its groove count, so the tool does not preset it. The drum maker or the parts supplier lists it for each drum.

Cables are sold in fixed lengths. Order the next standard length up. A cable that is too short cannot wrap the drum correctly.

What should I know before a cable is replaced?

That both cables are usually replaced together, and that the job starts with the spring tension.

  • A snapped or frayed cable means the other one has the same wear. Ask for both.
  • A technician unwinds the torsion springs before touching a cable. That step causes most DIY injuries.
  • Ask whether the drums and bottom brackets were checked. A worn drum groove frays new cable.
  • If the door came off its track, ask whether the track was checked for bends. See track repair.
  • Ask what cable diameter was fitted, and why. Heavier doors use thicker cable.

Can I replace a garage door cable myself?

No. The cable holds the bottom of the door against the full spring tension.

Cable work means winding and unwinding torsion springs, and that is the job that injures people. This page gives you a length so you can read a quote and talk to a technician. It is not a repair guide. See garage door repair for what the visit covers.

Questions this calculator answers

How long should a garage door lift cable be?
Floor to shaft center plus the allowance for your drum. On a standard-lift door that is a little longer than the door is tall. Order the next standard length up.
Why does the drum change the cable length?
The drum’s size and groove count set how much cable wraps onto it. Each drum model has its own allowance, listed by its maker.
Should both cables be replaced at once?
Usually, yes. Both cables have done the same work. If one has snapped or frayed, the other is close behind.
Can I replace a garage door cable myself?
No. Cable work means releasing and rewinding torsion spring tension, which can cause serious injury. Call a garage door repair company.
What does lift cable diameter depend on?
The door’s weight. Heavier doors use thicker cable. Ask what diameter was fitted and why.

Sources and methodology

Figures dated October 26, 2026. Last reviewed .

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