Flat iron plate sizes: which width do you need

Flat iron sizes chart

Use this as a starting point. Most people own one iron, and for them a 1 inch plate is the safest pick.

1/2 inch: short hair and details

Narrow plates get close to the root on short hair and handle bangs and the hairline without catching the forehead. They are also good for small bends and touch ups. On long or thick hair they are slow because each pass covers so little. The ghd Mini Styler is a 0.5 inch example; its listing also notes universal voltage, which makes it a common travel pick.

If short hair is your main use, see the best flat irons for short hair and how to flat iron short hair.

1 inch: the all rounder

A 1 inch iron is narrow enough to curl and wave, and wide enough to straighten shoulder length and long hair at a reasonable pace. Most premium lines have their flagship at this size: the ghd Platinum+, Gold and Chronos, the T3 SinglePass StyleMax, the BaBylissPRO Ultra Thin and TrueTension, and the Bio Ionic 10X are all listed as 1 inch.

Many 1 inch irons have rounded outer edges so you can twist and glide for curls. How to curl hair with a flat iron shows the technique, and the best flat irons for curls lists irons shaped for it.

1 1/4 to 1 1/2 inch: faster on longer hair

These widths cover more hair per pass, which saves time on medium to long hair. They can still make big, loose bends, but tight curls are harder. Listed examples include the BaBylissPRO Dual Ionic at 1 1/4 inch, the BaBylissPRO Prima3300 and T3 Lucea at 1 1/2 inch, and the Bio Ionic OnePass in a 1.5 inch size.

These are a good middle ground for thick hair that you also want to bend at the ends.

One thing to check at these widths is the plate edge. Irons with rounded outer housings are easier to turn for bends, while square edged irons are built mainly to press hair flat. If you want both speed and the option of a soft wave at the ends, look for a rounded body and a floating plate mount, and read the listing to confirm the exact width, since some models come in several sizes.

2 inch: long, thick and dense hair

Wide plates are built for speed on long, thick or very dense hair. You can take bigger sections, so a full head needs fewer passes. The trade off is reach: 2 inch plates struggle near the root on short hair and are not made for curling. Listed examples include the ghd Max Styler, the ghd Chronos Max and the BaBylissPRO Nano Titanium 2 inch. See the best flat irons for thick hair.

Flat irons for thick hair →

Thickness and texture change the choice

Length is the first filter, but thickness matters too. Fine hair often does well with a 1 inch iron even when long, because small sections already straighten quickly. Thick, coarse or curly hair may justify a wider plate even at shoulder length. For natural hair and silk presses, many people still prefer 1 inch for control near the root; see how to flat iron natural hair.

Plate length also helps. Some irons, such as the BaBylissPRO Ultra Thin with 5 inch plates per its listing, cover more hair lengthwise without making the iron wider.

• Fine hair, any length: 1 inch is usually enough
• Thick hair, shoulder length: 1 to 1 1/2 inch
• Thick hair, long: 1 1/2 to 2 inch
• Short hair or bangs: 1/2 to 1 inch
• Want curls too: 1 inch

Frequently asked questions

What size flat iron is best for long hair? 1 inch works if you also curl. For straightening only, 1 1/2 to 2 inch plates are faster on long hair, especially if it is thick.

Is a 1 inch or 1 1/2 inch flat iron better? 1 inch is more versatile and better for curling. 1 1/2 inch is faster for straightening medium to long, thicker hair.

What size flat iron is best for short hair? 1/2 inch for pixies and very short hair, 1 inch for bobs.

Do wider plates mean less heat on hair? Wider plates cover more hair per pass, which can mean fewer passes overall. They do not guarantee less damage; heat setting and technique still matter.