How to measure a garage door torsion spring: the four numbers, and the one you cannot read off the color

A supplier will ask you for four numbers and nothing else. Three of them you measure with a tape, and the fourth is the one most people get wrong, because the color code that is supposed to give it away is contradicted by the sources at the top of this very question. Here is how to read all four off a spring that has already broken, what is safe to touch and what is not, and the one question this page will not answer.

Four numbers identify a torsion spring: wire size, inside diameter, overall length and wind direction. Wire size comes from measuring 20 coils and dividing by 20. Inside diameter is usually stamped on the cone. Overall length is the relaxed coil body, cones excluded. Wind direction comes from the end of the wire, not from the color of the cone. If you would rather hand the whole thing to somebody, call (702) 744-7333 and we will size it on site.

This page is the specification question, not the diagnosis question

Two different questions bring people here and they need different answers, so it is worth separating them in the first paragraph rather than at the end. If what you want to know is which of your two springs failed, that is a diagnosis question, it takes about ten seconds to answer by eye, and it lives on our garage door spring repair page along with what the repair involves. This page answers the other one: you already know the spring is finished, and now somebody is going to ask you what size it was.

That somebody is a parts counter, a supplier website or a technician on the phone, and they all ask for the same four things. Three are tape measure work. The fourth is where this question goes wrong for most people, and the reason it goes wrong is not what you would expect: it goes wrong because the convention everybody quotes for it is not actually agreed on. We will get to that.

The four numbers, in the order a supplier asks for them

Written out as a spec, a torsion spring reads something like .225 x 2.0 x 32 right wind. That is wire size, inside diameter, overall length, wind direction. Everything below is how to get each of those four off a spring that is lying in your garage with a gap in the middle of it.

The residential wire range in that table is the figure Google is putting at the top of this exact question. We read its answer box for how to measure garage door torsion spring on 14 October 2026 and it gives .192 to .262 inch for residential springs. We are quoting it rather than our own range because it is the number the next person who searches this will see, and on this one it matches what comes off valley doors.

1. Wire size: count 20 coils, divide by 20, then round to a real size

Count 20 coils along the spring, measure that stack of 20 in inches, and divide the measurement by 20. If 20 coils measure four and a half inches, you have .225 wire. If they measure five inches, .250. The arithmetic is the whole method and it works on a broken spring, which is the only kind you should be measuring.

Two practical notes that make the difference between a number and the right number. First, push the coils tight before you count, especially either side of the break, because a spring that has snapped often has a stretched section at each end and those gaps will inflate your measurement. Second, mark the twentieth coil rather than trying to hold your place: a business card or a folded strip of paper slid between the coils is what the people who do this all day use, and it is the single tip worth taking from the videos sitting on page one of this question.

Then round to a real wire size rather than ordering the raw quotient. This is the step that gets skipped. DASMA, the association the door and spring manufacturers belong to, says to measure 10 or 20 coils and refer the result to a standard spring wire chart. IDC Spring, whose own measuring guide is sitting on page one of this search, says the same thing and specifically advises against reaching for calipers or a micrometer. The reason is plain once you have done it: the standard sizes are a few thousandths of an inch apart, and a tape measure laid across a stack of coils is not a precision instrument. The division puts you in the right neighborhood. The chart picks the house.

If the spring is distorted badly enough that you cannot count a clean 20, DASMA gives the way round it: count the total number of coils in the whole spring and multiply by the wire size to get back to a length you can trust.

2. Inside diameter: read the cone first, measure second

Look at the cone before you look for a tape. A good number of cones carry the inside diameter cast or stamped straight into the metal, either as a plain figure such as 1.75 or 2.0, or as a code such as P175 or P200, where the digits are the diameter in hundredths of an inch. P175 is a one and three quarter inch inside diameter. P200 is two inches. That is the number, read off the part, with no measuring error in it at all.

If the cone is painted over, rusted or simply blank, measure across the hollow center of the coil, inside edge to inside edge, and take it to the nearest sixteenth of an inch. That is DASMA's own tolerance for this measurement. Residential doors in this valley are almost always one of the two common sizes, so if your tape says something close to 1.75 or 2.0 you have your answer and the only thing left to decide is which one it is closer to.

Worth knowing before you go hunting: inside diameter is the number most likely to be legible on an old spring, because it is cast into the cone rather than painted onto the coils. Paint weathers off in a garage that hits 110 degrees in July. Casting does not.

3. Overall length: the relaxed coil body, cones excluded

Measure the steel coil body from one end to the other with the spring relaxed, and leave the cones out of the measurement. Include any coils that sit inside the cone, exclude the cone casting itself. Take it to the nearest quarter inch.

If the spring broke in two, which is the usual reason anyone is measuring one, measure both halves separately and add them together. Push the coils tight on each piece first, for the same reason as the wire-size count: the ends where the break happened will have opened up, and every stretched gap you measure is length you do not actually have. If there is an obviously stretched section, the trade habit is to take about an inch back off the total rather than order long.

One hard rule sits over this whole section and it is the reason the page keeps saying relaxed. A spring that is still wound cannot be measured, and nobody should be trying. IDC Spring's guide puts it as plainly as we would: torsion springs cannot be measured while active. If the broken spring is still up on the shaft and you want the length, that is a job for whoever takes it down.

4. Wind direction: read the wire end, because the color code is not agreed

Determine wind direction by looking at the end of the spring where the wire comes out, not by the color of the cone. That is DASMA's instruction, word for word in substance: by looking at the end of the spring, determine if you have a right hand or left hand wound spring. IDC Spring puts a readable version on it: if the spring end points clockwise it is left wound, and if it points counter clockwise it is right wound.

Now the part that nobody writes down, and it is why this page exists in the shape it does. We read the three sources sitting at the top of this question on 14 October 2026 and they do not agree with each other about the color code.

So one source says black is left, another says black is left in one paragraph and red is left in the next, and the trade association does not use color as a method. If you order a spring off a color you have a coin flip dressed up as a specification, and a spring wound the wrong way will not hold a door: it unwinds itself the first time the door is operated.

Look at the photograph further up this page, which is a spring off a real valley door. The color on that assembly is a yellow band around the coils and red paint on the head of the set screw. Neither of those is a wind direction code. A painted band on the coil body is generally a wire-size code and the codes differ between makers, so treat it the way you would treat a hunch: it narrows your guess and it does not replace the measurement. The red on that bolt is a set screw marking. It tells you nothing about which way the spring turns.

The practical answer, and it costs nothing: photograph both ends of the spring and the center bracket before anything comes down, and send the photographs with your four numbers. Every supplier counter would rather look at a picture than argue about a color, and a photograph of the wire end settles wind direction in one second.

How do you figure out what springs you need for your garage door?

If the old spring is readable, you copy it. If it is not, the size is calculated from the door rather than guessed. The second path needs the weight of the door, the height of the door and the size of the cable drums, and it is how a technician sizes a spring for a door whose original springs are missing, mismatched or were wrong to begin with. It is also why the honest answer to what size spring a 16 by 7 door takes is that there is no single one: an insulated steel double and a single skin steel double of the same opening can be a hundred pounds apart, and the spring follows the weight, not the opening.

That last point is worth holding on to if you are about to buy a part. Copying a readable spring is safe because the door told you the answer once already. Picking a size off a chart keyed to door dimensions alone is not the same thing, and it is the most common way a door ends up with springs it was never meant to have.

What this page will not tell you, and why

Today's People Also Ask box on this exact search carries the question how many turns for a torsion spring on a 7 foot garage door. We are not going to answer it, and we would rather say so plainly than leave you wondering whether we forgot.

Reading the four numbers off a spring that has already broken is safe. Winding one is a different activity entirely. A wound torsion spring on a double door is holding the kind of energy that does not forgive a slipped bar, and the moment where it goes wrong is not the dramatic one people imagine: it is the quiet one, a bar seated a quarter of the way out of its hole, taking a hand with it. Turn counts are the number that gets somebody hurt when they are read off a webpage by a person who has not got the right bars, the right spring, or a second pair of hands. We publish prices, we publish what we carry on the truck and we publish what we will and will not do. We do not publish turn counts.

The same line applies to the set screws and the stationary cone. IDC Spring's own precaution is the right one to repeat here: no coils should be touched while the spring is still on the bars above the door, and the set screws and the bolts on the stationary cone are not yours to loosen. Whether the replacement is a job you want to take on at all is a separate question and we answer it honestly on the spring repair page rather than here.

Measuring safely: what you can touch and what you cannot

If the broken spring is still up on the shaft and you simply want the numbers, the realistic options are to photograph what you can read from the floor, or to have whoever is doing the work read it off when the spring comes down. There is no measurement on this page worth standing on a ladder under a loaded shaft for.

What a Las Vegas door does to these numbers

Valley doors arrive at this question sooner than doors elsewhere, and the reason is the one we have written about at length on why garage door springs break so often here, so we will not re-argue it. The short version for anyone standing in a garage with a tape measure: a builder grade 10,000 cycle pair cycled four times a day is roughly a seven year spring on paper, and heat and fine dust in this valley push a door toward the short end of that rather than the long end. The practical consequence for measuring is that a lot of the springs being measured in Las Vegas garages are original builder springs, which means the number you copy off them is the number the builder's door needed when it was hung, and that is often the lightest spring that would do the job.

That is worth knowing before you order a matching pair. Copying the old spring is the safe default and it is what we have recommended all the way down this page. It is also an opportunity to ask one question, which is whether a higher cycle spring in the same wire and diameter is available for the door, because a pair rated for more cycles is the difference between buying this repair once and buying it again in a few summers.

Where to actually buy the part in the valley: Home Depot, Lowe's and Ace stock springs and opener hardware across the valley and Grainger carries the trade sizes, and we have written the whole picture of that, with what the parts cost on their own, on our Las Vegas garage door parts page. We do not run a counter and we do not sell hardware for you to fit yourself. What we carry is torsion springs in the common sizes on the truck, which is why most spring calls here finish on the first visit.

What the pair costs installed, if you would rather not order anything

The published Las Vegas bands are $295 to $425 for a standard torsion pair installed and $395 to $525 for a high-cycle pair, with a single spring at $185 to $265. Of that, the springs themselves are $75 to $125 for a pair; the rest is the labor, the tools and the trip, which is the honest reason a part bought separately saves less than people expect. Springs are replaced in pairs: when one of a matched pair has reached the end of its cycle count, the other is within months of the same place, and fitting one new spring against one tired one puts the door out of balance.

Every one of those figures is on the Las Vegas price list with the part and the labor shown separately. You get a flat written price before any work starts, and if you decide not to go ahead, the look costs you nothing.