Chili Heat Scale

Chili heat is measured in Scoville Heat Units (SHU): a bell pepper scores zero, a jalapeño a few thousand and the hottest peppers over a million. This interactive heat scale lines up 17 popular chilies, shows how many times hotter one is than another, and helps you swap one pepper for another in a recipe without surprising anyone at the table.

The Scoville scale

The Scoville scale was devised by the American pharmacist Wilbur Scoville in 1912. His original test diluted a pepper extract in sugar water until a panel of tasters could no longer detect the heat; the dilution factor gave the score. Today laboratories measure the capsaicinoid content directly with high-performance liquid chromatography (HPLC) and convert it to Scoville Heat Units. Pure capsaicin is about 16 million SHU.

Chili heat chart

Ranges are typical published values; individual peppers vary with variety, climate, soil and ripeness. The Carolina Reaper held the Guinness World Record for the hottest pepper for about a decade until Pepper X was recognised in 2023.

How to use the heat comparer

1. Choose a pepper you know — for example the jalapeños in your usual salsa.
2. Choose the pepper you want to compare or swap in.
3. Enter how many of the first pepper your recipe uses.
4. Read how many times hotter or milder the second pepper is and a rough equivalent amount.

The comparison uses the middle of each typical range, so treat it as a starting point and taste as you go.

Worked example

A salsa recipe uses 2 jalapeños. Jalapeños typically measure 2,500–8,000 SHU (about 5,250 in the middle) and serranos 10,000–23,000 (about 16,500), so serranos are roughly 3.1 times hotter. For similar heat you would use about two-thirds of one serrano instead of two jalapeños. Swapping in a habanero (about 225,000 SHU mid-range) would call for less than 5% of one pepper — a very small sliver.

Where the heat is

Capsaicin is concentrated in the pale membranes (placenta) that hold the seeds, not in the seeds themselves, though seeds pick some up. Removing the membranes and seeds makes a pepper noticeably milder. Wear gloves when cutting hot peppers, don’t touch your eyes, and wash knives and boards well.

Cooling the burn

• Milk, yoghurt or sour cream: casein helps wash capsaicin away.
• Starch: rice, bread or tortillas give the capsaicin something else to cling to.
• Sugar or honey: a little sweetness can take the edge off.
• Avoid water: it spreads the oily capsaicin around rather than removing it.
• Wait it out: the burning sensation fades as nerve receptors recover, usually within minutes.

Cooking with chilies

• Fresh vs dried: drying concentrates flavour; dried chilies often taste smokier and fruitier.
• Roasting: charring peppers mellows raw heat and adds sweetness.
• Infusing: whole chilies in a sauce give gentle heat; remove them when it tastes right.
• Timing: heat builds as sauces simmer, so add chilies early for mellow heat or late for sharp heat.
• Balance: acid (lime, vinegar), sugar and fat all soften the perception of heat.

Chili pepper species

Most common chilies belong to five cultivated species. Capsicum annuum includes bell peppers, jalapeños, cayenne and poblanos; Capsicum chinense includes habaneros, Scotch bonnets, ghost peppers and the Carolina Reaper; Capsicum frutescens includes tabasco peppers and many bird’s eye types; Capsicum baccatum includes the fruity ají amarillo; and Capsicum pubescens includes the hairy-leaved rocoto. The species with the hottest peppers, chinense, also tends to have the most fruity aroma.

Growing your own chilies

Chilies need warmth, light and a long season. Sow seeds indoors 8–10 weeks before the last frost — super-hots can take several weeks to germinate and need warmth of around 25–30 °C — then pot on and move outdoors or into a greenhouse when nights stay warm. Heat levels rise with sunshine and slight water stress as fruit ripens. Pick fruit regularly to encourage more flowers.

Safety with super-hot peppers

Peppers above about a million SHU can cause severe pain, vomiting and, rarely, more serious reactions. Use tiny amounts, keep them away from children and pets, ventilate the kitchen when cooking them, and don’t eat super-hots on a dare or on an empty stomach. People with heart conditions, ulcers or reflux should be especially careful.

The printable templates

The template pack includes a chili heat scale poster, hot sauce recipe cards, a chili growing log from seed to harvest, a hot sauce tasting scorecard and an Excel recipe heat calculator — PDF, Word and Excel.