Learning how to curl hair with a flat iron mostly comes down to one wrist movement, and once you have it, one tool does both straight and curly. Below: the twist technique step by step, how to switch between beach waves and defined curls, what changes for short hair, the safe heat range, and which irons make it easiest.
Before you start: dry hair, heat protectant, the right heat
Three things decide whether your curls look smooth or fried.
- Bone-dry hair. The American Academy of Dermatology (AAD) says flat irons should be used on dry hair on a low or medium heat setting, no more often than every other day. Stylist Craig Taylor told woman&home that using straighteners on wet hair "can cause hair damage".
- A heat protectant. The AAD's tips for healthy hair say to use low or medium heat and "a product to protect your hair from the heat". Celebrity hairstylist Sophie Rose Gutterman told NBC Select that sprays suit tools that touch the hair directly, like a flat iron.
- The lowest heat that works. More on numbers below.
If your hair is naturally curly or coily, Taylor suggests a blow-dry first so the finished curls come out even.
How to curl hair with a flat iron: 8 steps
1. Section your hair, bottom layer first
Clip your hair into horizontal layers; ghd's US tutorial uses 2-inch layers, starting with the bottom one. Then work in small pieces of 1 to 2 inches. Sam Villa's guide warns that a section that's too big slips out of the plates and leaves a crease, and keeps even wave sections no wider than the plates.
2. Set the heat low to medium
Fine hair needs much less heat than thick hair. Hairstylist Shawn Harvey told NBC Select that fine hair can be straightened at around 250°F, medium-thick hair at 250–350°F, and thick, coarse hair at 350–400°F. ghd presets its irons to 365°F. If you're between settings, pick the lower one.
3. Mist on heat protectant, section by section
Spray each piece lightly from mid-lengths to ends just before you iron it. Give it a few seconds to dry first: the AAD says flat irons belong on dry hair.
4. Clamp near the root and angle the iron down
Clamp near the root, leaving a small gap so the hot plates don't touch your scalp, with the tip of the iron pointing toward the floor at a slight diagonal. ghd's tutorial calls this placing the styler "diagonally with the nose of the styler pointing downwards".
5. Twist the iron away from your face
This is the whole trick. Rotate your wrist so the iron turns half a turn for a soft bend, or one full turn for a round curl. As woman&home's guide puts it, "the greater the rotation, the rounder the curl". Hold the iron with your fingertips rather than your palm, Taylor says, so your hand doesn't get stuck partway through the turn.
6. Glide down to the ends without stopping
Keep the twist and pull the iron down the section in one smooth, steady motion. Speed sets the shape: Sam Villa says "for a tighter curl, use a slower, more deliberate motion", and to move faster for looser waves. Don't pause; a flat iron that stops in one spot leaves a dent.
7. Pick a direction: one way, or alternating
Curl the pieces around your face away from your face, which woman&home's guide calls more flattering. For the rest, curling every piece the same way gives uniform curls, as in ghd's US tutorial. Alternating direction looks more natural and textured, which ghd's step-by-step and woman&home both suggest.
8. Let every curl cool, then finish
This step is where most curls fail. ghd says to let each curl cool before you touch it, and Sam Villa says never re-curl a section until it has cooled. Once your whole head is done, shake the curls out with your fingers or a wide-tooth comb and mist with a flexible, brushable hairspray.
Beach waves using a flat iron vs defined curls
The same iron does both. You change four things.
| Beach waves | Defined curls | |
|---|---|---|
| Section size | Medium (up to your plate width) | Small, about 1 inch |
| Twist | Half turn | One full turn |
| Glide speed | Start slow, speed up toward the ends | Slow and even the whole way |
| Ends | Leave the last inch or so straight | Curl right to the tips |
| Finish | Brush or comb out once cool | Shake out gently with fingers |
For beach waves, Sam Villa suggests starting slow and speeding up near the ends, "almost not even curling the ends". L'Oréal Paris's tutorial adds that keeping the hair slack, not tightly wound, gives the looser wave. ghd has a shortcut: make firm curls, let them cool completely, then brush through and they open into soft waves.
For defined curls, go the other way: smaller sections, a full turn, a slower glide, and every piece curled in the same direction.
How to curl short hair with a flat iron
Short hair works, but there's less length to wrap, so make two changes.
- Use a narrow iron. For short hair, Taylor recommends a straightener with narrow plates: "Too big, and you won't get enough movement into the hair."
- Use half a turn, not a full one. woman&home's method for short hair is half a turn, then tug the iron down the rest of the way while keeping that half-turn.
L'Oréal Paris suggests clamping as close to the roots as you safely can, twisting away from your face, then clamping and releasing your way down to the ends. Our tip for a bob: leave the last half-inch straight so the ends don't flip under.
Best flat iron for curling hair: what to look for
Most flat irons can curl, but two features make it much easier.
- Rounded edges or a rounded barrel. Anari LaBoard, lead hair trainer at Blushington, told TODAY that "most flat irons with a rounded shape can easily create a nice curl or wave, making them more versatile than flat-edged models".
- 1-inch plates. L'Oréal Paris's guide says a straightener "only one or two inches wide" is the right size, and that wide paddles only suit hair below the mid-back. woman&home's rule of thumb: the narrower the plate, the tighter the curl. For most hair, 1 inch is the sweet spot.
Adjustable heat also matters if your hair is fine or color-treated. Once you've curled, a few frizzy pieces are normal; our guide on how to fix frizzy hair covers smoothing them without more heat.
Picks that help
Two irons with the rounded shape that curling needs, a heat protectant spray and a brushable hairspray. Start with the iron that fits your budget; the other two make the curls last.
INFINITI PRO by Conair SmoothWrap 1" Dual Ion Flat Iron
Best for: a drugstore flat iron for curling hair that you can also use to straighten.
- Conair says its 1-inch ceramic plates have curved edges designed to glide over hair "without creases", which is what you want when you twist.
- Five heat settings, so fine hair can stay on a low setting.
- We couldn't find a named editorial review of this model; our pick is based on its shape and the brand's specs.
ghd Platinum+ Styler 1" Flat Iron
Best for: a splurge flat iron for beach waves, if you'd rather not think about temperature.
- ghd says its "round barrel" is designed for "sleek styles, curls, or waves", and the iron is preset to 365°F with no dial to get wrong.
- Brooklyn stylist David Jones-Muñoz told NBC Select he keeps one at his salon for its "small curve to help create a beachy wave".
- The trade-off: one fixed temperature. If your hair is very fine or fragile, an iron you can turn lower may suit you better.
Bumble and bumble Hairdresser's Invisible Oil Heat/UV Protective Primer
Best for: a mid-range heat protectant spray for dry or frizz-prone hair.
- The brand says it helps protect from heat tools up to 450°F and contains a six-oil blend plus UV filters.
- NBC Select includes it in its heat protectant roundup.
- Our tip: it's an oil-based primer, so on fine hair use a light mist and keep it off your roots.
L'Oréal Paris Elnett Satin Extra Strong Hold Hairspray
Best for: a budget-friendly hairspray that holds curls but still brushes out.
- L'Oréal says it gives "brushable hold" without stiffness and is humidity-resistant, made with six ingredients.
- L'Oréal sells an unscented version in the US, and its own flat-iron tutorial finishes curls with it.
- Hold the can about 12 inches away; for waves, spray a brush and run it through instead.
FAQs
How do I curl my hair with a straightener?
Clamp a 1- to 2-inch section near the root, twist the straightener half a turn to a full turn away from your face, and glide it slowly to the ends. Work on dry hair with heat protectant, at low to medium heat. Let each curl cool before you touch it.
Why do my flat iron curls have dents or creases?
Usually the iron stopped moving, or the section was wider than the plates and slipped. Sam Villa's fix is to keep the iron moving and work in smaller sections. woman&home's guide also says not to clamp down hard, which leaves bend marks.
Why won't my flat iron curls hold?
ghd says the usual cause is brushing curls before they've cooled. Let every curl set fully. On fine hair, ghd suggests a light spray for grip rather than heavy product, which can make curls drop.
What heat should I use to curl hair with a flat iron?
The AAD says low or medium. As a rough guide for flat ironing from hairstylist Shawn Harvey: around 250°F for fine hair, up to 350°F for medium-thick hair, and 350–400°F only for thick, coarse hair. In a 2019 lab study, a flat iron left visible damage on the hair cuticle, and the authors stressed controlling temperature.
Is curling hair with a flat iron worse than a curling iron?
Both use direct heat, and the AAD's advice is the same for both: low heat, short contact, and not every day. The AAD suggests using a flat iron no more often than every other day. For curling irons, the AAD says to leave the iron in place for only a second or two; keeping a flat iron gliding follows the same idea.
What is the best flat iron for curling hair?
Look for rounded edges and 1-inch plates. The Conair SmoothWrap is a drugstore option with curved edges; the ghd Platinum+ is the splurge stylists use for waves.
Give yourself one slow practice run with the iron off, and your second real attempt will look like you've been doing it for years.