Generational Garage Doors
Spring Calculator
Advanced / Calibration
= Output
Set the door up and tap Figure Springs.
We stock standard 10,000-cycle springs on the truck — $310–$570 installed, single or double car, one or two springs. Mid and high-cycle springs, and springs for custom doors, are confirmed on site and made to order with about a 3-day lead time.
Current Spring
Current spring is treated as 10,000 cycles. Turns for a 7' door on 4" drums unless you set the door on the Engineer tab.
New Spring
= Output
Enter the spring on the door and the wire and ID you want to convert to.
= Output
Every wire size that can deliver that IPPT at that ID, with length and cycle life at the turns you entered.
Built by Dustin Cantu, owner and technician at Generational Garage Doors. Auto mechanic who got into garage doors and never left — 10 years in the industry, CA Contractor's License #1113495. The math here is what runs on the truck. About Dustin → · Updated Sept 2026
How to Use the Spring Calculator
- Pick the track. Standard, Hi-Lift, or Vertical, then the track radius. Low headroom is under the radius row.
- Pick the drum. Read the number stamped on the drum — 400-8, 5250-18, and so on. The list shows the SSC, DNS, and OMI equivalents.
- Set the door size. Slide width and height. Cable length updates as you go.
- Enter the weight. Best is a scale reading with the springs unhooked. No scale? Pick the closest door type and it'll estimate.
- Springs per door, then tap Figure Springs. You get the closest stock match with a hot/heavy check, plus a mid and high-cycle option.
- Converting? Use the Convert tab: enter the spring on the door now and the wire and ID you want, and it returns the length.
Measure the wire with a spring wire gauge. Eyeballing .234 vs .243 is a coin flip, and one gauge size is a 15% change in torque. Check it with a gauge, or measure 20 coils with a tape and divide by 20. The gauge is the one that's right every time.
Spring Wire Color Codes
Most torsion springs have a paint dab on the cone end that tells you the wire size. Confirm it with a gauge — paint fades and colors get reused across suppliers.
| Color | Wire |
|---|---|
| Yellow | .207" |
| White | .218" |
| Red | .225" |
| Brown | .234" |
| Green | .243" |
| Gold | .250" |
| Blue | .262" |
| Silver | .273" |
| Purple | .283" |
| Orange | .295" |
| Light Blue | .307" |
| Black | .313" |
The Math Behind It
Torque. Door weight × drum radius is what the springs hold with the door closed. Divide by the number of springs for torque per spring.
Turns. Door height ÷ drum circumference + overwind. High lift adds the vertical travel on the tapered section; pitched track adds residual turns to hold the door on the incline.
IPPT. E · d⁵ ÷ (10.8 · (ID + d) · active length), with E = 28.5 million psi for oil-tempered wire and the length inside the cones deducted.
Stress and cycle life. Stress at full wind is 32 · T · K ÷ (π · d³) with the Wahl curvature correction. Stress depends on wire size, not length. Cycle life scales with the stress ratio, calibrated so one wire size up is roughly 1.6× the cycles — which is why a 25,000-cycle spring is two sizes up and longer, not just longer.
Every constant is editable under Advanced so the tool can be tuned to a supplier chart.
See a Spring Replaced
A real torsion spring replacement, start to finish. More on spring replacement →
Spring Calculator FAQ
What is IPPT on a garage door spring?
IPPT is inch-pounds per turn — the torque a torsion spring delivers for each full turn of wind. Multiply IPPT by the turns and you get the torque holding the door closed. Two springs with the same IPPT balance the same door regardless of wire size or length.
How many turns do you wind a garage door torsion spring?
Door height divided by the drum circumference, plus about three-quarters of a turn. A 7-foot door on 4-inch drums is about 7.4 turns; an 8-foot door about 8.4. High-lift and vertical-lift drums change the count, which is why the calculator asks for the track type.
Why is a high-cycle garage door spring longer?
Cycle life comes from the stress in the wire. Thicker wire means lower stress and more cycles, but thicker wire is also stiffer, so the spring has to be longer to bring the torque per turn back to what the door needs. Same door, same turns, more steel.
How do I know what wire size my garage door spring is?
Measure it with a spring wire gauge — the difference between .234 and .243 is hard to see and is about a 15% change in torque. Without a gauge, measure 20 coils with a tape and divide by 20. Wire color codes help too: yellow .207, white .218, red .225, brown .234, green .243, gold .250, blue .262.
What does it mean when a garage door is hot or heavy?
Hot means over-sprung — the door wants to fly up and won't stay down. Heavy means under-sprung — the door drifts down and the opener strains to lift it. Within about 4% of the required torque is balanced; up to 10% can usually be tuned with a quarter turn.
Can I replace my own garage door torsion spring?
We don't recommend it. A wound torsion spring stores enough energy to break bones, and the wrong spring size is the most common cause of repeat failures. Use the calculator to understand what your door needs, then have it installed. Same-day spring replacement across Contra Costa and Solano Counties runs $310–$570 for stock springs, single or double car, one or two springs, with a 3-year parts warranty. Custom doors may need made-to-order springs.
More on Garage Door Springs
Garage door spring replacement — what it costs, how long it takes, why the $79 ads are bait, and what we install. Same-day across Contra Costa and Solano Counties.
Pricing — single and dual spring replacement, openers, cables, rollers, and new doors, all upfront.
Spring repair reviews — what homeowners said after the loud bang.
Garage door openers — a door that's off balance works the opener to death. If yours is straining, check the springs first.
The blog — real job walkthroughs, including a torsion spring replacement start to finish.
Engineered from spring formulas, not a supplier chart — verify against the spring you order. Right-wind (red cone) goes on the left of the center bearing, left-wind (black cone) on the right, viewed from inside. Winding torsion springs is dangerous; this is for understanding your options, not a DIY guide. Broken spring? We replace them same-day — (925) 316-8384.