Perm Rod Size Chart: Which Rod Gives Which Curl
Perm rod sizes from 1/8 inch to jumbo, with the curl each one gives, how long your hair needs to be and what to ask your stylist for, including loose perms and beach waves.
Built by Maya Brooks, reviewed by Hazel Casey
The size of the perm rod decides almost everything about how a perm turns out. A small rod gives tight, springy curls. A big rod gives loose waves or just a little body. Rod colors are different from brand to brand, so the safest way to talk about perm rods is by their width.
This perm rod size chart shows the common rod sizes in inches and millimeters, the curl each one gives, how long your hair needs to be, and what to say to your stylist.
Quick answer: Smaller perm rods make tighter curls and bigger rods make looser curls. Rods from 1/8 to 1/4 inch (3 to 6 mm) give tight curls, 3/8 to 1/2 inch (10 to 13 mm) give medium, bouncy curls, 5/8 to 3/4 inch (16 to 19 mm) give a loose perm, and 1 inch (25 mm) and up gives beach waves or a body wave. Your hair needs to wrap around the rod at least twice, so short hair needs small rods.
Perm rod size chart
| Rod size | Metric | Curl result | Min. hair length |
|---|---|---|---|
| 1/8 in | 3 mm | Very tight, small spirals, close to a coily texture | 1+ in |
| 3/16 in | 5 mm | Tight ringlets with lots of volume | 2+ in |
| 1/4 in | 6 mm | Tight, springy curls that stay defined | 2+ in |
| 3/8 in | 10 mm | Defined curls with spring, a classic curly look | 3+ in |
| 1/2 in | 13 mm | Bouncy, medium curls, the most common perm result | 4+ in |
| 5/8 in | 16 mm | Loose, soft curls | 5+ in |
| 3/4 in | 19 mm | Big, loose curls that relax into waves | 6+ in |
| 1 in | 25 mm | Loose waves and a beachy bend | 8+ in |
| 1 1/4 in and up | 32 mm | Body and volume with only a slight bend | 10+ in |
Minimum hair length is a rough guide: the hair should go around the rod about two and a half times for a full curl. Rod colors are not standard, so a gray rod from one brand can be a different size from a gray rod from another. Check the size on the package, or ask your stylist which size they are using.
Loose perm chart: rods for soft curls and waves
A loose perm uses medium-large to large rods, usually 5/8 inch (16 mm) and up. It is the most popular perm today because it looks like naturally wavy hair and grows out softly.
- Loose curls: 5/8 inch (16 mm) rods. Soft, rounded curls that relax a little over time.
- Big loose curls: 3/4 inch (19 mm) rods. Curls that turn into waves after a few weeks.
- Beach waves: 1 inch (25 mm) rods, often wrapped loosely or flat so the bend looks undone.
- Body wave: jumbo rods or flexi rods, 1 1/4 inch (32 mm) and up. Adds volume and movement without visible curls.
Many stylists mix two rod sizes, like 5/8 and 3/4 inch, so the curls do not look too uniform. If you want to see if your hair already bends on its own, try the hair type quiz first.
Types of perms and the rods they use
| Perm type | Rods | Result |
|---|---|---|
| Classic perm | Small to medium, rolled from ends to roots | Even, all-over curls |
| Spiral perm | Long spiral rods, wrapped vertically | Corkscrew curls, best on long hair |
| Beach wave perm | Large rods, wrapped loosely | Soft, undone waves |
| Body wave | Jumbo rods or flexi rods | Volume and a slight bend |
| Root perm | Rods only at the roots | Lift at the crown, no curls at the ends |
| Stack perm | Rods only on the lower half | Curls at the bottom, smooth on top |
| Digital (hot) perm | Heated rods, usually large | Loose curls that show most when dry |
How to choose the right perm rod size
- Start with the curl you want. Tight curls need small rods. Waves need large rods.
- Check your hair length. Short hair can only wrap around small rods. Long hair can take any size, but small rods on long hair give a lot of volume.
- Think about your hair texture. Fine hair often drops curl, so many stylists go one size smaller. Thick, heavy hair can pull curls loose, so a smaller size helps there too.
- Allow for relaxing. Most perms loosen a little in the first week or two. Pick a rod slightly smaller than the curl in your photo.
- Get a test curl. A good stylist will test one section first, especially on colored hair.
Who should not get a perm
- Hair that is very damaged, gummy when wet or breaking.
- Hair that was bleached recently. Perm solution and bleach both weaken the hair, so many stylists say no or wait.
- Hair with a relaxer or a keratin treatment that has not grown out.
- A scalp that is sore, scratched or irritated.
If your hair feels weak or stretchy, our protein or moisture quiz can help you sort out what it needs first, and the hair porosity test tells you how well it will take in the solution. For curl inspiration, browse our curly hairstyles and 90s hairstyles.
How to care for a new perm
- Wait about 48 hours before washing, so the curl can set.
- Use a sulfate-free shampoo and a rich conditioner.
- Detangle with a wide-tooth comb or your fingers, never a brush on dry curls.
- Scrunch in a curl cream and air-dry or use a diffuser.
- Sleep on a satin pillowcase or in a loose pineapple to keep curls from flattening.
A perm usually lasts about three to six months before it relaxes or grows out. Track how long you have grown on our hair length chart, and use the hair salon tip calculator after the appointment.
Keep going: find your curl pattern with the hair type quiz and check how your hair takes in product with the hair porosity test.
