Enter your garage door weight and setup to get matched torsion spring sizes.
Standard residential doors only. Sectional doors on a standard-lift track with a 4" or 5.25" drum. High-lift, vertical-lift and commercial setups need different drums - contractors can use the pro conversion calculator.
This free spring size calculator starts from the door, not the old spring. Tell it what the door weighs and how tall it is, and it lists torsion springs that balance it: wire size, length and inside diameter, with the lifting capacity, turns and cycle life of each. It is the right tool when the old springs are broken, missing, or never lifted the door properly.
A 150 lb, 16 ft by 7 ft door on 15" radius track and 4" drums, with two springs and a 2" inside diameter, can use a matched pair of .218 x 2" x 32" springs. Each lifts 74.9 lb at 7.94 turns, about 59,000 cycles. The finder also lists thinner and thicker wire options, so you can pick the size your supplier stocks.
Start from the door: enter its weight, width, height, track radius and drum above, and the calculator lists springs that balance it. If you still have the old springs and they worked well, you can measure them instead and check them in the spring calculator. The buying guide walks through both ways.
Use the garage door weight calculator to estimate it from the size, material and model. The exact way is a scale under the door with the spring tension released, which is a job for a trained technician.
Two springs share the load and are the usual choice on double doors, while many single doors use one. Doors over 500 lb need at least three springs, and the calculator will not offer fewer.
Two springs with the same wire size but slightly different lengths, chosen so that together they lift the exact weight of the door. It gives a closer match than two identical springs when no single length fits.
10,000 cycles is the standard spring. At 3 to 4 opens and closes a day that is roughly 7 to 9 years. Choose 20,000 cycles or more for a door used many times a day. Longer-life springs use thicker wire and are longer, so they cost more.
Glass in the top section only makes that section the heaviest. It reaches the horizontal track first, so the springs finish the lift carrying less weight. The calculator takes 0.625 lb per foot of door width off the lift (10 lb on a 16 ft door) so the door does not drift up. Doors with glass in every section need no correction.
Most home garage doors use a 4" cable drum. 5.25" drums are used on some taller and heavier doors. The size is usually stamped on the drum. High lift and vertical lift doors use special drums and are not covered here.
Yes. It is free with no sign-up, and it works in feet and pounds or in millimetres and kilograms.