I work with hundreds of Pilates studios, and one problem comes up over and over from the teachers in them. They learn to teach on one brand of reformer. Then they cover a class at another studio, look down at the springs, and nothing makes sense.
The colors are different. The labels are different. A red spring that felt like a medium at their home studio now feels heavy. A setup they could pick in their sleep suddenly needs a guess.
It is a small thing, but it slows teachers down right when a class is about to start. So I built a free tool to fix it. Pick the brand you know, pick the springs you use, and pick the brand in front of you. It shows you the closest match. Try it below.
Use the result to get into the right range, then adjust by feel. If you are not sure, start a little lighter and build up. Below I explain how the springs line up, brand by brand, so you can trust what the tool shows you.
Why spring colors don't mean the same thing across brands
Here is the trap. Most teachers learn springs by color. That works fine until you change machines, because there is no shared color code in Pilates. Each brand picked its own.
The clearest example is the red spring. On a Balanced Body reformer, red is a medium spring. On a Stott, a Peak, or a BASI, red is the heavy one. Same color, very different load. If you grab red on a new machine and expect medium, you can get a real surprise.
This table shows how the most common colors flip around:
| Spring color | Lighter on these brands | Heavier on these brands |
|---|---|---|
| Red | Medium on Balanced Body, Align-Pilates | Heavy on Stott, Peak, BASI |
| Blue | Light on Balanced Body, Peak, Align-Pilates | Medium on Stott, BASI, Flexia |
| Yellow | Very light on Balanced Body, Align-Pilates | Light on BASI, medium on Peak |
So color is the wrong thing to trust. What you can trust is how heavy the spring is meant to feel. That is what the tool matches.
The simple way to think about springs: five levels
Forget colors for a minute. Across every brand, a spring is really doing one of five jobs. Once you think in these five levels, every machine makes sense.
| Level | What it is for |
|---|---|
| Extra light | Gentle support. Rehab, arm work, and exercises where you need control more than load. |
| Light | Smaller muscles and slower, careful movement. |
| Medium | The everyday setting for a lot of full-body work. |
| Heavy | Footwork, legs, and stronger pushing exercises. |
| Extra heavy | The most load. Only some brands offer this. |
One thing worth saying here. A heavier spring does not always mean a harder exercise. The spring is there to support you too. In a lot of moves, a lighter spring asks for more strength and control, not less. So heavier is not better. It is just different.
Reformer spring conversion chart for every brand
This is the full picture. Each row is one of the five levels. Each column is a brand. Find your level, then read across to the machine you are using.
| Level | Balanced Body | Stott | Peak | BASI | Align-Pilates | Flexia | Classical | AeroPilates |
|---|---|---|---|---|---|---|---|---|
| Extra light | Yellow | None | None | None | Yellow | White | None | None |
| Light | Blue | White | Blue | Yellow | Blue | Orange | None | Yellow |
| Medium | Red | Blue | Yellow | Blue | Red | Blue | None | Black (base) |
| Heavy | Green | Red | Red | Red | Green | Black | All springs | Red |
| Extra heavy | None | Black | None | None | None | None | None | None |
None means that brand does not make a spring at that level. Classical reformers are a special case, which I explain below.
Spring guide for each reformer brand
Here is the short version for each brand, including the standard set of springs the machine ships with and the quirks to watch for.
Balanced Body
This is the brand a lot of teachers know best, since it is what many big chains use. The colors run yellow for very light, blue for light, red for medium, and green for heavy. Here is the catch most people miss. A standard Balanced Body machine ships with three reds, one blue, and one yellow. It does not come with the green. So on most Balanced Body reformers, red is the heaviest spring you have on the bed, even though red is rated as a medium. That is why some teachers cue red as the full spring.
Merrithew (Stott)
Stott uses white for light, blue for medium, red for heavy, and black for extra heavy. Stott also labels springs by percent, like 100 percent, 50 percent, and 25 percent. Good idea, but the numbers are a little off. The real strengths are closer to 100, 66, and 41 percent. So treat the percent labels as a rough guide, not exact math.
Peak Pilates
Peak keeps it to three springs. Blue is light, yellow is medium, and red is heavy. Note that yellow here is a medium, while yellow on Balanced Body is very light. This is one of the bigger color traps when teachers move between these two brands.
BASI Systems
BASI uses yellow for light, blue for medium, and red for heavy. One extra thing to know. On BASI machines, the gear setting also changes how heavy the spring feels, so the same spring can feel a bit different depending on the gear.
Align-Pilates
Align uses yellow for very light, blue for light, red for medium, and green for heavy. Align is one of the few brands that publishes real resistance numbers in kilograms, which makes it a useful reference point. A standard machine comes with one green, two reds, and two blues.
Flexia
Flexia is a newer smart reformer. It uses white for very light, orange for light, blue for medium, and black for heavy. A standard machine ships with one black, two blues, one orange, and one white.
Classical reformers (Gratz and similar)
Classical machines work in a different way. They use four springs that are all the same, with no colors at all. You set the load by how many springs you clip on, not by which color. These springs are also firmer than most modern heavy springs, so a classical setup tends to feel heavier than the number suggests. When you convert to or from classical, treat it as the roughest match of all.
AeroPilates
AeroPilates is the odd one out because it uses bungee cords, not steel springs. It comes with several black cords that are all the same, and you can add a red cord for more or a yellow for less. Cords pull in a more gradual way than springs, so the feel is close in intent but not the same.
How to convert a full set of springs, not just one
Most of the time you are not using one spring. You are using a few at once. The total load is what matters, so swapping one spring for one spring on another brand will not always feel right.
That is what the Full combination tab in the tool is for. Set the springs you had on at your old studio, and it works out the closest total on the new machine. For example, two reds and a blue on a Balanced Body comes out close to one white and two blues on a Stott. You would never guess that from the colors, but the total load lines up.
What a conversion chart can't tell you
I want to be honest about the limits, because no chart can be perfect here. A few things change the feel no matter what the springs are called.
- Springs get heavier as the carriage moves out. A spring at rest is much lighter than the same spring stretched far. So one number can never tell the whole story.
- Your body changes the load. A taller or heavier person presses more weight on the same spring than a smaller person does.
- Classical springs feel firmer than modern ones, even at the same level.
- Cords are not springs, so AeroPilates will feel different even when the level matches.
- Springs wear out. Tension drops over time, so old springs feel lighter. Replace them about every two years, or sooner if you see any rust, kinks, or gaps.
So use the chart to get close, then trust your body. When in doubt, go lighter and add from there.
Common questions about reformer springs
Is a red spring heavy or medium?
It depends on the brand. Red is a medium on Balanced Body and Align-Pilates. Red is the heavy spring on Stott, Peak, and BASI. This is the most common mix-up when teachers switch machines.
What do the spring colors mean?
Color tells you the load level, but only within one brand. There is no shared color code across brands, so the same color can mean a different load on a different machine. Match by load level, not color.
How many springs should I use?
It depends on the exercise. Footwork and leg work usually use more springs. Arm and core work often use fewer. Remember that more springs is not always harder, since the springs also support you.
Can I use one brand's springs on another reformer?
No. Springs from one brand are not made to fit another brand's machine, and mixing them is not safe. Only use the springs made for your reformer.
How often should I replace reformer springs?
About every two years, or every 2,000 hours of use. Replace them right away if you see rust, kinks, or gaps in the coil. A worn spring can break during a class, which is a real safety risk.
Are classical springs heavier?
They feel firmer. Classical reformers use four uniform springs and set the load by count. Because of how they are built, a classical setup tends to feel heavier than a modern heavy spring at the same level.
A quick note from me
I made this tool because the teachers and studio owners I work with deal with this every week, and there was no simple way to do it. If it saves you a few seconds of guessing before a class, it did its job. Feel free to share it with your team or print the chart for your studio.
I am the founder of StudioGrowth, and I spend my days helping Pilates studios run without the busywork. If you want to see how we help, take a look at our pilates studio software.
