Psychrometric Saturation Vapor Pressure, Dew Point & Absolute Humidity Calculator

Derive air dew point, vapor pressure (kPa), and moisture density (g/m³).

Dew-Point Temperature
17.63 °C
Absolute Humidity (Vapor Density) 14.6 g/m³
Partial Water Vapor Pressure 2.02 kPa
Saturation Vapor Pressure (100% RH) 3.36 kPa
Inputs
°C
Ambient air dry-bulb temperature in °C.
%
Relative humidity percentage (RH %).
Results & Graph
Dew-Point Temperature
17.63 °C
Absolute Humidity (Vapor Density)
14.6 g/m³
Partial Water Vapor Pressure
2.02 kPa
Saturation Vapor Pressure (100% RH)
3.36 kPa

Dew-Point Temperature

Graph 1 • Dry Bulb Celsius Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 °C 16.1 °C 32.2 °C 50%: 5.43 °C 5.4 50% 75%: 11.53 °C 11.5 75% 100%: 17.63 °C 17.6 100% 125%: 23.72 °C 23.7 125% 150%: 29.8 °C 29.8 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Dew-Point Temperature 17.63 °C Absolute Humidity (Vapor Density) 14.6 g/m³ Partial Water Vapor Pressure 2.02 kPa Saturation Vapor Pressure (100% RH) 3.36 kPa
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Dew-Point Temperature17.63 °CAbsolute Humidity (Vapor Density)14.6 g/m³Partial Water Vapor Pressure2.02 kPaSaturation Vapor Pressure (100% RH)3.36 kPa
Summary: At 26°C dry-bulb and 60% RH, dew point is 17.63°C, partial vapor pressure is 2.02 kPa, and absolute moisture content is 14.6 g/m³.
Summary: At 26°C dry-bulb and 60% RH, dew point is 17.63°C, partial vapor pressure is 2.02 kPa, and absolute moisture content is 14.6 g/m³.
⚡ Send result to: Scientific →Ohm's Law & Voltage Drop →Molarity, HP & Dew Point →
Interactive chart & math engine powered by CalculatorGraph

Formula & Mathematical Methodology: Psychrometric Air Physics & Engineering Equation

Psat = 0.61078 × exp(17.27·T / (T + 237.3))
Pv = Psat × (RH/100)
AbsHumidity = 2165 × Pv / (T + 273.15)
P_sat = 0.61078 × exp(17.27·T / (T + 237.3)); P_v = P_sat × (RH/100); AbsHumidity = 2165 × P_v / (T + 273.15)
  • dryBulbCelsius: Dry Bulb Celsius (°C)
  • relativeHumidityPct: Relative Humidity Pct (%)

Rounding: Physical constants follow CODATA/NIST values; output quantities display to 2 decimal places.

Worked Example: Physics & Engineering Benchmark: Psychrometric Air

Derive air dew point, vapor pressure (kPa), and moisture density (g/m³).

  1. Enter the physical dimensions, electrical parameters, or thermodynamic state variables.
  2. Apply the governing equation: P_sat = 0.61078 × exp(17.27·T / (T + 237.3)); P_v = P_sat × (RH/100); AbsHumidity = 2165 × P_v / (T + 273.15).
  3. Inspect the primary SI output, derived quantities, and 3 visual SVG graphs.
Result: Computes Psychrometric Air via P_sat = 0.61078 × exp(17.27·T / (T + 237.3)); P_v = P_sat × (RH/100); AbsHumidity = 2165 × P_v / (T + 273.15).

Frequently Asked Questions

What equation powers the Psychrometric Saturation Vapor Pressure, Dew Point & Absolute Humidity Calculator?

It evaluates P_sat = 0.61078 × exp(17.27·T / (T + 237.3)); P_v = P_sat × (RH/100); AbsHumidity = 2165 × P_v / (T + 273.15) using IEEE-754 double precision and renders three synchronized SVG plots.

Can I test parameter sensitivity across multiple values?

Yes. Graph 1 automatically plots a 50%–150% parameter response curve, and you can pin up to 3 custom scenarios.

Are all units consistent with SI standards?

Yes. Each input field specifies its exact SI or engineering unit and converts internally where needed.

Science & Engineering · Thermodynamics & Heat Transfer

Psychrometric Saturation Vapor Pressure, Dew Point & Absolute Humidity Calculator: inputs, method, and how to read the result

Derive air dew point, vapor pressure (kPa), and moisture density (g/m³).

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Dry Bulb Celsius: Ambient air dry-bulb temperature in °C.
  • Relative Humidity Pct: Relative humidity percentage (RH %).

What the calculation includes

With the default values shown, Dew-Point Temperature is 17.63 °C. The calculation follows Psychrometric Air Physics & Engineering Equation; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Dry Bulb Celsius from 26 °C to 29 °C changes Dew-Point Temperature from 17.63 °C to 20.44 °C. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard SI physical constants (g = 9.80665 m/s², c = 299,792,458 m/s, σ = 5.670374×10⁻⁸ W·m⁻²·K⁻⁴).
  • Engineering reference model; apply appropriate safety factors and empirical calibration for critical hardware designs.

Scope: SI / NIST Physics & Engineering Standard Check the assumptions and limitations against your situation before relying on the estimate.

More in Science & Engineering: Scientific Calculator, Ohm's Law, Wire Voltage Drop & Resistor Series/Parallel Calculator, Molarity, Density, Engine Horsepower & Dew Point / Weather Calculator.