Beauty Calculators
Heat styling temperature.
Pick your hair type to see a conservative temperature range for a flat iron or curling iron in both Celsius and Fahrenheit, and check whether the setting you use is too hot. When unsure, go lower. Runs in your browser.
Your hair and tool
Suggested range
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Worked example
You have healthy medium hair and run your flat iron at 180 C (356 F). The conservative range for medium hair is 150 to 175 C (302 to 347 F), so 180 C is above it. Dropping to 170 C (338 F) puts you inside the range, and a slower pass or a second pass at that heat is gentler than one pass at 180 C.
Ranges used
| Hair type | Celsius | Fahrenheit |
|---|---|---|
| Fine, bleached or damaged | 120 to 150 | 248 to 302 |
| Normal or medium, healthy | 150 to 175 | 302 to 347 |
| Coarse, thick or resistant, healthy | 175 to 190 | 347 to 374 |
These are cautious stylist rules of thumb, not a published standard or a manufacturer limit. Widely repeated dermatologist and stylist advice is to use the lowest heat setting that works; this guide also never recommends above 200 C (392 F). Many tools show only a dial or low / medium / high, so check with a thermometer or the tool's manual. Conversion: F = C x 9 / 5 + 32.
Not medical advice. Heat can burn the scalp and skin as well as hair. Keep tools away from skin, never use them on wet hair unless the tool is made for it, and stop if hair smells burnt, smokes or feels brittle.
Sources and basis (checked 2026-10-05): the bands are TNAADO's conservative rule of thumb, not a published standard; temperature conversion is exact.
FAQ
What temperature should I set my flat iron?
For healthy medium hair, 150 to 175 C (302 to 347 F). Fine or damaged hair should stay at 120 to 150 C (248 to 302 F), and healthy coarse hair at 175 to 190 C (347 to 374 F). Start low.
Is 450 degrees too hot for hair?
Yes. 450 F is about 232 C, above the 200 C (392 F) ceiling this guide uses. It is much more likely to damage hair than a lower setting.
What heat is safe for bleached hair?
Bleached and damaged hair is more fragile, so stay at 120 to 150 C (248 to 302 F) or lower, use heat protectant, and limit how often you style.
What is 350 F in Celsius?
About 177 C. The formula is C = (F - 32) x 5 / 9.
Does the same temperature apply to curling irons and flat irons?
Use the same conservative ranges for both. Curling irons hold the hair against the barrel longer, so many people go to the lower end of the range.