How to use: Calculate relative and absolute humidity from temperature and dew point. Enter Temperature and Dew Point in same units (Fahrenheit or Celsius). Results show: Relative Humidity percentage (amount of moisture air holds compared to maximum at that temperature) and Absolute Humidity g/m³ (actual mass of water vapor per volume of air). Relative humidity changes with temperature even if moisture content stays constant. Absolute humidity measures actual water content. Ideal indoor relative humidity: 30-50% (below 30% = dry skin/static, above 60% = mold growth). Used for: HVAC system design, indoor air quality, weather analysis, agricultural planning, and industrial humidity control.