Spice Heat Level Calculator
Calculate the average Scoville heat level when combining two different peppers or hot ingredients by weight or count. Ideal for recipe developers and spice enthusiasts blending custom heat profiles.
About this calculator
The Scoville scale measures the concentration of capsaicin compounds in peppers, expressed in Scoville Heat Units (SHU). When you mix two peppers in different quantities, the resulting heat level is a weighted average of both, not a simple sum. The formula is: blendedSHU = ((pepper1Scoville × pepper1Amount) + (pepper2Scoville × pepper2Amount)) / (pepper1Amount + pepper2Amount). This weighted average reflects the dilution effect: adding a large quantity of a mild pepper will pull the blend's heat down toward that pepper's SHU, and vice versa. For reference, a jalapeño sits at 2,500–8,000 SHU, a cayenne at 30,000–50,000 SHU, and a habanero at 100,000–350,000 SHU. This formula helps recipe developers achieve a repeatable, targeted heat level.
How to use
You want to blend 3 jalapeños (5,000 SHU each) with 1 habanero (200,000 SHU). Enter pepper1Scoville = 5,000, pepper1Amount = 3, pepper2Scoville = 200,000, pepper2Amount = 1. The calculation is: blendedSHU = ((5,000 × 3) + (200,000 × 1)) / (3 + 1) = (15,000 + 200,000) / 4 = 215,000 / 4 = 53,750 SHU. Your blend lands at approximately 53,750 SHU — roughly in the cayenne range. Adding a fourth jalapeño would shift the result: (215,000 + 5,000) / 5 = 44,000 SHU, pulling the heat down slightly.
Frequently asked questions
How does the Scoville scale measure the heat of peppers?
The Scoville scale was originally developed by pharmacist Wilbur Scoville in 1912 using a human taste panel — a pepper extract was diluted in sugar water until heat was no longer detectable, and the dilution factor became the SHU value. Modern labs use high-performance liquid chromatography (HPLC) to directly measure capsaicin concentration, then convert to SHU for consistency with historical values. A bell pepper scores 0 SHU, a jalapeño ranges from 2,500 to 8,000 SHU, and the current world-record hottest pepper, Pepper X, exceeds 2.6 million SHU. The scale is logarithmic in practice, meaning small SHU differences at high values represent enormous perceptual heat differences.
What happens to a pepper blend's heat level when you add a mild pepper to a hot one?
Adding a mild pepper to a hot one always reduces the weighted average SHU of the blend — this is the dilution principle behind the calculator. The more mild pepper you add relative to the hot one, the greater the reduction. For example, mixing equal parts jalapeño and habanero brings the blend's SHU to the midpoint of the two values. This is also how commercial hot sauces are formulated: a small amount of an extremely hot pepper like ghost pepper is blended with large quantities of milder peppers to achieve a palatable but flavorful heat level.
Why does the perceived heat of a dish sometimes differ from the calculated Scoville level?
Scoville units measure raw capsaicin concentration, but perceived heat in a finished dish is influenced by many additional factors. Fat, dairy, and acids (like vinegar or citrus) chemically bind to capsaicin molecules and reduce their availability to heat receptors, lowering perceived burn. Cooking also breaks down some capsaicin, particularly at very high temperatures over long periods. Conversely, alcohol can enhance capsaicin absorption, making a dish feel hotter than its SHU suggests. Individual tolerance also varies widely — a level that is mildly spicy to one person can be intensely painful to another based on receptor sensitivity and prior exposure.