Degree Days Table: Heating degree days by Base temperature
Reference table of heating degree days for Degree Days across a range of base temperature values — exact, engine-computed figures you can read off at a glance.
Degree Days Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Heating degree days
8.0
- Cooling degree days
- 0.0
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Degree Days Calculator
The Degree Days Calculator works out your heating degree days, along with 1 related figure in an instant. Enter base temperature and average daily temperature and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the base temperature.
- Enter the average daily temperature.
- Read off your heating degree days, together with cooling degree days — the calculator updates automatically, with no button to press.
Worked example
For example, with base temperature of 18 °C and average daily temperature of 10 °C, the heating degree days is 8.0.
| Base temperature | 18 °C |
|---|---|
| Average daily temperature | 10 °C |
| Heating degree days | 8.0 |
|---|---|
| Cooling degree days | 0.0 |
Results are estimates for educational use, not professional advice.
Key terms explained
- Mean
- The average of a set of numbers — their sum divided by how many there are.
Frequently asked questions
They measure how far the average temperature is from a base, indicating heating or cooling demand. A base of 18°C with a 10°C day is 8 heating degree days.
It is the outdoor temperature below which heating is needed (or above which cooling is needed). 18°C is a common base.
Heating degree days count how far below the base it is; cooling degree days count how far above. Only one applies on a given day.
They help estimate energy use for heating and cooling and compare seasons or buildings on a consistent basis.
Enter the base temperature. Enter the average daily temperature. Read off your heating degree days, together with cooling degree days — the calculator updates automatically, with no button to press.
Related guides
How to Calculate Degree Days: Formula, Steps & Examples
Learn how to calculate Degree Days — the formula explained step by step, with worked examples and a free calculator to check your answer.