What this calculator does
Q10 describes how much a biological or chemical rate changes for a 10 degree rise in temperature. A Q10 of 2 means the rate doubles, which is typical for many enzymatic processes over their working range. A Q10 near 1 means temperature has little effect.
The measurement can be taken across any temperature interval, not just ten degrees, because the formula normalises it. Rates measured 25 degrees apart give a Q10 comparable with rates measured 5 degrees apart, which is what makes the coefficient useful for comparing across studies.
The formula
Q10 is the ratio of the two rates raised to the power of ten divided by the temperature difference. When the interval happens to be exactly 10 degrees, that exponent is 1 and Q10 is simply the rate ratio. Over any other interval the exponent rescales it to what a 10 degree change would have produced.
| Term | Meaning |
|---|---|
| Q10 | The factor by which a rate changes per 10 degree temperature rise. |
| Q10 of 2 to 3 | The typical range for enzymatic and metabolic processes. |
| Q10 near 1 | Temperature-insensitive, characteristic of physical processes such as diffusion rather than chemical ones. |
| Thermal breakdown | Above an enzyme optimum the rate falls as protein denatures, and Q10 loses its meaning there. |
The inputs explained
| Field | What to enter |
|---|---|
| Rate at T₁ | Reaction rate at the lower temperature. |
| Rate at T₂ | Reaction rate at the higher temperature, in the same units. |
| T₁ (°C) | The lower temperature in degrees Celsius. |
| T₂ (°C) | The higher temperature in degrees Celsius. |
When to use it
Characterising a metabolic response
Q10 is the standard summary of how strongly a physiological rate depends on temperature, and it is what comparative studies report.
Correcting a rate to a standard temperature
Measurements taken at different temperatures can be adjusted to a common reference once Q10 is known, which makes them comparable.
Predicting the effect of warming
Applying a known Q10 to a projected temperature change gives a first estimate of how a rate would shift, within the range where the coefficient holds.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
What Q10 does each rate increase give?
A fixed 10 degree interval with increasing rates at the higher temperature.
| Rate at 30°C | Q₁₀ | Rate ratio R₂/R₁ | Temperature span |
|---|---|---|---|
| 4 | 2.000 | 2.000 | 10.0 °C |
| 8 | 4.000 | 4.000 | 10.0 °C |
| 16 | 8.000 | 8.000 | 10.0 °C |
Questions
What is a typical Q10 value?
Between 2 and 3 for most enzymatic and metabolic processes, meaning a 10 degree rise roughly doubles or triples the rate. Physical processes such as diffusion have Q10 closer to 1.2 to 1.5, since they depend on temperature far less strongly than chemistry does.
Does Q10 hold across all temperatures?
No, only within the range where the process behaves normally. Above an enzyme optimum the protein denatures and the rate falls, so a Q10 measured across that point is meaningless. The coefficient describes the rising portion of the curve.
Can the interval be other than 10 degrees?
Yes, and it usually is. The exponent of 10 divided by the temperature difference normalises whatever interval was measured to a 10 degree equivalent, which is what lets studies using different intervals be compared.
What does a Q10 below 1 mean?
The rate falls as temperature rises. This is unusual in the normal range and generally indicates either that the optimum has been passed and denaturation is under way, or that the process is limited by something that itself becomes less favourable at higher temperature.
For the temperature dependence of plant water demand, see the vapor pressure deficit calculator. For enzyme kinetics at a fixed temperature, see the Michaelis-Menten calculator.