Dew Point Calculator

Approximate dew point from temperature and relative humidity (°C or °F).

Dew Point Calculator helps you approximate dew point from temperature and relative humidity (°C or °F). Enter air temperature and relative humidity, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Dew Point calculator does Dew Point Calculator is built for everyday questions — shopping, home, travel, hobbies, and tech. Approximate dew point from temperature and relative humidity (°C or °F). You enter air temperature and relative humidity, then Simple Calculators computes the result instantly. Defaults are chosen to be easy to read — change any field to match your situation. How the math works Choose Units (°C or °F), then enter the Air temperature and Relative humidity. Using the Magnus approximation with the temperature in °C: a = 17.27 × T ÷ (237.7 + T) + ln(humidity ÷ 100), and dew point = 237.7 × a ÷ (17.27 − a), where ln is the natural logarithm. It is accurate enough for everyday weather but not for scientific work. The formula: a = 17.27 × T ÷ (237.7 + T) + ln(RH ÷ 100); dew point = 237.7 × a ÷ (17.27 − a). T is the air temperature in °C, RH is the relative humidity in percent, and ln is the natural logari…