How to Measure Garage Door Springs

1. Wire diameter. Measure 20 coils, then divide by 20. Measuring 10 coils and dividing by 10 works as a cross-check. Wire size is the single most important number.
2. Inside diameter. Measure the inside of the coil, or read it off the cone stamp. Common catalog options include 1.75", 2", and 6" commercial sizes.
3. Overall length. Measure the coiled body only, excluding the cones.
4. Wind direction. Look at the end of the spring: if the last coil points clockwise it is one wind, counter-clockwise the other. Most doors use one left-wind and one right-wind spring.

1. Door height. 7 ft doors typically use 25" relaxed-length springs; 8 ft doors typically use 27".
2. Relaxed length. Measure the spring body at rest, excluding hooks or loops.
3. Weight rating. Each spring is rated for roughly half the door weight. Colored ends identify the rating — confirm the rating rather than trusting a faded color.

Never measure a spring that is still under tension unless you are trained and equipped for it. Torsion springs store enough energy to cause serious injury. Read our spring safety notes before working on a door.