Torsion Spring Size Calculator
Enter door weight, height, and track radius to find the correct spring specifications and replacement cost
lbs
Single car steel door: 100-150 lbs. Two-car door: 200-350 lbs. Wood: add 50-100 lbs
Recommended Wire Diameter
0.000 in
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Sources & Methodology
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DASMA -- Door and Access Systems Manufacturers Association Technical Standards
Industry standards body for garage door systems including torsion spring specifications, IPPT calculation methods, wire gauge sizing tables, and cycle rating standards
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HomeAdvisor -- Garage Door Spring Replacement Cost Data 2025
Aggregated contractor quotes and homeowner-reported costs for garage door spring replacement across US regions used to establish labor and parts cost benchmarks
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OSHA -- Spring Tension Hazard Safety Guidelines
OSHA guidance on high-tension spring hazards in construction and maintenance settings, referenced for safety warnings and professional installation recommendations
Methodology: Turns = door height (inches) / (2 x pi x track radius inches). IPPT = (door weight / number of springs) / turns, rounded to 2 decimal places. Wire diameter selected from DASMA-based IPPT lookup table: under 6 IPPT = 0.192 in, 6-8 = 0.207 in, 8-10 = 0.218 in, 10-13 = 0.225 in, 13-17 = 0.243 in, 17-21 = 0.262 in, 21-26 = 0.283 in, over 26 = 0.306 in. Spring cost: standard 10,000-cycle spring $30-75 each; high-cycle 25,000-cycle $80-150 each; ultra-cycle 100,000-cycle $200-400 each. Professional labor: $150-250 per service call for 1-2 springs. DIY assumes parts-only cost. All costs are estimates; actual pricing varies by region and contractor.
Last reviewed: March 2026 — spring sizing methodology verified against DASMA technical data sheets and industry torsion spring specification guides.
Garage Door Spring Calculator -- Complete 2025 Guide to Torsion Spring Sizing
Selecting the correct garage door torsion spring requires matching the spring specifications to three key variables: door weight, door height, and track radius. An incorrectly sized spring fails prematurely, unbalances the door, and can damage the opener motor. This calculator uses the industry-standard IPPT (Inch-Pounds Per Turn) method used by professional garage door technicians to specify replacement springs.
How Torsion Spring Sizing Works -- The IPPT Formula
Turns = Door Height (inches) / (2 x 3.14159 x Track Radius inches)
Then: IPPT = (Door Weight / Number of Springs) / Turns
Example: 150 lb door, 7 ft height, 3-inch radius track, 1 spring.
Turns = 84 / (2 x 3.14159 x 3) = 84 / 18.85 = 4.46 turns
IPPT = (150 / 1) / 4.46 = 33.6 IPPT
Wire size selected: 0.306 inch (heaviest standard gauge)
Same door with 2 springs: IPPT = (150 / 2) / 4.46 = 16.8 IPPT = 0.243 in wire (lighter per spring)
Example: 150 lb door, 7 ft height, 3-inch radius track, 1 spring.
Turns = 84 / (2 x 3.14159 x 3) = 84 / 18.85 = 4.46 turns
IPPT = (150 / 1) / 4.46 = 33.6 IPPT
Wire size selected: 0.306 inch (heaviest standard gauge)
Same door with 2 springs: IPPT = (150 / 2) / 4.46 = 16.8 IPPT = 0.243 in wire (lighter per spring)
Torsion Spring Wire Size vs IPPT -- Reference Table
| IPPT Range | Wire Diameter | Typical Door Weight (1 spring) | Notes |
|---|---|---|---|
| Under 6.0 | 0.192 inch | Under 60 lbs | Light doors, small panels |
| 6.0 - 7.9 | 0.207 inch | 60-80 lbs | Light single car doors |
| 8.0 - 9.9 | 0.218 inch | 80-100 lbs | Standard single car doors |
| 10.0 - 12.9 | 0.225 inch | 100-130 lbs | Most common residential |
| 13.0 - 16.9 | 0.243 inch | 130-170 lbs | Heavy single or dual spring |
| 17.0 - 20.9 | 0.262 inch | 170-210 lbs | Two-car doors (dual spring) |
| 21.0 - 25.9 | 0.283 inch | 210-260 lbs | Heavy two-car or wood doors |
| 26.0 and above | 0.306 inch | 260+ lbs | Very heavy or wood doors |
Garage Door Spring Replacement Cost -- 2025 Benchmarks
| Job Type | DIY Parts Only | Professional Installed | Lifespan |
|---|---|---|---|
| Standard spring (10,000 cycle) | $30-$75 each | $150-$350 total | ~7 years at 4 cycles/day |
| High-cycle spring (25,000) | $80-$150 each | $220-$450 total | ~17 years at 4 cycles/day |
| Ultra-cycle spring (100,000) | $200-$400 each | $450-$750 total | ~68 years at 4 cycles/day |
| Emergency/after-hours | N/A | +$50-$150 surcharge | Same day service premium |
Why Two Springs Are Better Than One
Installing two springs instead of one provides three major benefits. First, each spring operates at half the load, extending their lifespan significantly. Second, if one spring breaks, the second spring prevents the door from dropping suddenly -- a major safety advantage. Third, a dual-spring system keeps the door balanced even during uneven wear. The cost difference is typically only $25 to $75 for the second spring on an already-open service call.
⚠️ Safety warning -- torsion springs are extremely dangerous: A torsion spring under full tension stores hundreds of foot-pounds of energy. If a winding bar slips during installation or if the spring is released suddenly, it can cause severe lacerations, broken bones, or death. Never use a screwdriver or wrench instead of proper winding bars. Never stand directly in front of or behind the spring while winding. Professional installation from a licensed garage door technician is strongly recommended -- the $150 to $250 service fee is far less than the cost of an emergency room visit.
Frequently Asked Questions
How much does garage door spring replacement cost?
Garage door spring replacement costs $150 to $350 for a single torsion spring professionally installed, or $200 to $500 for two springs. The spring itself costs $30 to $75 for standard 10,000-cycle springs. Labor runs $75 to $200 per service call. Most garage door companies charge a flat rate covering springs, installation, and adjustment. Emergency after-hours service adds $50 to $150 above standard rates.
How do I find the right garage door spring size?
To find the correct torsion spring: weigh the door or estimate by material, measure door height in feet and track radius in inches, calculate turns using the formula (height x 12) divided by (2 x pi x radius), then calculate IPPT by dividing door weight by number of springs by turns. Select wire diameter from the IPPT lookup table -- this calculator does all of this automatically.
How long do garage door springs last?
Standard torsion springs are rated for 10,000 cycles -- one cycle equals one open and one close. At 4 cycles per day that is approximately 7 years. High-cycle springs at 25,000 cycles last about 17 years. Ultra-cycle springs at 100,000 cycles can last 50 to 70 years. Spring life is shortened by cold weather, rust, lack of lubrication, and incorrect sizing for the door weight.
Can I replace a garage door spring myself?
Torsion spring replacement is one of the most dangerous DIY projects due to extreme stored energy. A spring under tension can release hundreds of foot-pounds of force instantly if a winding bar slips. If attempting DIY: use only proper winding bars (never a screwdriver), wear safety glasses, never stand in the spring's path, and always release tension fully before disassembly. Most professionals strongly recommend hiring a licensed technician.
What is IPPT in garage door springs?
IPPT stands for Inch-Pounds Per Turn -- the torque rating of a torsion spring per full wind. It is calculated by dividing the door weight per spring by the number of turns required for that door height and track radius. Correct IPPT matching ensures the spring fully counterbalances the door weight at all positions. A spring with too low an IPPT will not fully open the door; too high and the door will fly up uncontrolled.
What is the difference between torsion and extension springs?
Torsion springs mount above the door on a horizontal shaft and twist to store energy. Extension springs run alongside the horizontal tracks and stretch. Torsion springs are safer (energy contained on the shaft), last longer (10,000 to 100,000 cycles vs 5,000 to 10,000), and provide smoother door movement. Extension springs require safety cables to prevent dangerous projectiles if they break. Most modern homes use torsion springs.
Should I replace one or both garage door springs?
Always replace both springs at the same time even if only one broke. Both springs have the same cycle count and will fail within a similar timeframe. Replacing both during a single service call saves a second labor charge of $75 to $200. The cost of a second spring at $30 to $75 is minimal. A dual-spring system also keeps the door balanced and provides a safety backup if one spring fails suddenly.
What causes garage door springs to break?
Springs break primarily from metal fatigue after reaching the end of their cycle life. Cold weather is the most common trigger as metal contracts under low temperatures and stress increases. Rust and corrosion accelerate failure by creating stress points in the metal. Incorrect spring sizing for the door weight causes overloading and premature failure. Lack of lubrication with garage door lubricant spray 2 to 3 times per year also shortens spring life significantly.
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