What is the Scoville scale?
The Scoville scale measures how hot a chilli pepper is, in Scoville heat units (SHU). It is named after the American pharmacist Wilbur Scoville, who devised the original test in 1912 [2]. A sweet bell pepper scores 0 SHU, a jalapeño 2,500 to 8,000, a habanero 100,000 to 350,000 and the hottest peppers grown today well over 2 million [1][2]. Pure capsaicin, the chemical that makes chillies hot, is rated at about 16 million SHU [2].
The number tells you how far the heat would have to be diluted before people could no longer taste it. A pepper rated 5,000 SHU would need about 5,000 parts of sugar water to one part of pepper extract before the burn disappears.
How Scoville heat units are measured
In Scoville’s original test, an exact weight of dried pepper is dissolved in alcohol to extract the capsaicinoids, then diluted in sugar water. The dilutions are given to a panel of five trained tasters, getting weaker each time, until at least three of them can no longer detect any heat. The level of dilution at that point is the pepper’s Scoville rating [2].
Because it depends on human tasters, the method is imprecise. Palates differ, tasters’ mouths quickly become desensitised, and results could vary by as much as 50% between laboratories [2]. Since the 1980s, heat has instead been measured with high-performance liquid chromatography (HPLC), which measures the concentration of capsaicinoids directly. The result, in parts per million, is multiplied by 15 to convert it to Scoville heat units [2].
Heat also varies within a single variety. Growing conditions, climate, soil and ripeness all change a pepper’s capsaicin content, which is why most peppers are given a range rather than one number [2].
Scoville scale chart of common peppers
These are typical ranges for well-known peppers, taken from the chart above by Reddit user u/Life_Ad_2142, which ranks 166 peppers [1]:
| Pepper | Scoville heat units | Heat level |
|---|---|---|
| Bell pepper | 0 | None |
| Banana pepper, pepperoncini | 0 to 500 | Mild |
| Poblano (ancho when dried) | 1,000 to 1,500 | Mild |
| Anaheim, padrón | 500 to 2,500 | Mild |
| Jalapeño (chipotle when smoked) | 2,500 to 8,000 | Medium |
| Fresno | 2,500 to 10,000 | Medium |
| Serrano | 10,000 to 23,000 | Medium |
| Chile de árbol | 15,000 to 30,000 | Medium hot |
| Cayenne, tabasco | 30,000 to 50,000 | Hot |
| Thai (bird’s eye) chilli, peri-peri | 50,000 to 100,000 | Hot |
| Habanero, Scotch bonnet | 100,000 to 350,000 | Very hot |
| Ghost pepper (bhut jolokia) | 855,000 to 1,041,427 | Extremely hot |
| Trinidad Moruga scorpion | 1,200,000 to 2,000,000 | Extremely hot |
| Carolina Reaper | 1,400,000 to 2,200,000 | Extremely hot |
| Pepper X | 2,693,000 | Hottest on record |
Published ranges differ slightly between sources. Wikipedia, for example, gives 1,500,000 to 2,500,000 for the Carolina Reaper [2]. Treat any single figure as a guide, not a fixed value.
What is the hottest pepper in the world?
Pepper X. Guinness World Records recognised it as the world’s hottest chilli in 2023, at an average of 2,693,000 SHU [3]. It was bred by Ed Currie, who also created the Carolina Reaper, which held the record from 2013 until Pepper X replaced it [3][4]. When the Reaper was certified, tests at Winthrop University in South Carolina gave an average of 1,641,183 SHU for the batch tested [4].
The chart also lists the Apollo pepper at 3,000,000 SHU and Dragon’s Breath at 2,480,000 [1]. These are claims by their growers and have not been officially verified; Wikipedia notes that Dragon’s Breath has not been confirmed [2]. Until they are, Pepper X is the hottest pepper on record.
Mild, medium and hot peppers
For cooking, the scale breaks down into rough bands:
- No heat to mild (0 to 2,500 SHU): bell peppers, pimentos, banana peppers, poblanos and Anaheims. These add flavour with little burn and suit stuffing, roasting and salads.
- Medium (2,500 to 30,000 SHU): jalapeños, Fresnos, serranos and chipotles. Most salsas and Mexican dishes sit here.
- Hot (30,000 to 100,000 SHU): cayenne, tabasco, Thai bird’s eye and peri-peri. Use sparingly; a little goes a long way.
- Very hot (100,000 to 350,000 SHU): habaneros and Scotch bonnets, common in Caribbean cooking and hot sauces.
- Superhot (above about 850,000 SHU): ghost peppers, scorpions, the Carolina Reaper and Pepper X. Handle them with gloves and keep them away from your eyes.
The heat is concentrated in the pale pith (placenta) that holds the seeds rather than in the flesh, so removing it makes a pepper noticeably milder [3].
Capsaicin and other hot compounds
The scale is designed for the capsaicinoids found in chillies, but Scoville units are also used to compare other substances. Pure capsaicin is rated at about 16 million SHU [2]. Law-enforcement pepper spray has been reported at 500,000 to 5 million SHU, depending on dilution [2]. Resiniferatoxin, from the sap of certain spurge plants, is about 1,000 times hotter than capsaicin, at an estimated 16 billion SHU, far too strong for any human taste test [2].
Questions about the Scoville scale
How hot is a jalapeño on the Scoville scale?
2,500 to 8,000 SHU, which counts as medium heat [1].
What is hotter than a Carolina Reaper?
Pepper X, at an average of 2,693,000 SHU, recognised by Guinness World Records in 2023 [3].
How hot is a ghost pepper?
About 855,000 to just over 1 million SHU, more than a hundred times hotter than a jalapeño [1].
Who invented the Scoville scale?
Wilbur Scoville, an American pharmacist, in 1912 [2].
Is the Scoville scale accurate?
Only roughly. The original taste test varied by up to 50% between labs, and heat varies with growing conditions. Modern HPLC testing is more precise [2].
Sources
- u/Life_Ad_2142, [OC] Hot peppers ranked on the Scoville scale, r/dataisbeautiful, August 2024, the original chart (data from pepperscale.com and allhotsauces.com, per the creator).
- Wikipedia, Scoville scale.
- Wikipedia, Pepper X.
- Wikipedia, Carolina Reaper.
Last reviewed 2 November 2026
