Salinity Calculator
Compute water salinity from conductivity and temperature (PSS-78), or convert between PSU, g/kg, and mg/L.
Use the Salinity Calculator
Typical seawater: ~50–55 mS/cm
Valid range: −2 °C to 35 °C
Enter values and click Calculate to see results.
Salinity Result (PSS-78)
PSU / ppt
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g/kg
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mg/L
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Conductivity ratio Rt computed at T = — °C; Rt must be ≥ 0.005 and calculated salinity must be ≤ 42, at −2 to 35 °C.
Unit Conversion Results
PSU
—
g/kg
—
mg/L
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PSU ≈ g/kg (dimensionless ratio vs. mass fraction, difference < 0.01%). mg/L is estimated using salinity-dependent density at an assumed 25 °C.
Summary
Compute water salinity from conductivity and temperature (PSS-78), or convert between PSU, g/kg, and mg/L.
How it works
- Choose the "Conductivity → Salinity" tab to compute PSU from conductivity and temperature.
- Enter conductivity in mS/cm and water temperature in °C.
- The calculator applies the PSS-78 polynomial to return practical salinity in PSU.
- Switch to the "Unit Converter" tab to convert a known salinity value between PSU, g/kg, and mg/L.
- Results update instantly as you type.
Use cases
- Oceanographers computing seawater salinity from CTD sensor readings.
- Aquarium hobbyists checking saltwater tank salinity levels.
- Environmental scientists monitoring estuary or river conductivity.
- Lab technicians converting salinity units for reports and databases.
- Students verifying PSS-78 calculations for coursework.
- Water quality engineers assessing brackish or saline groundwater.
Frequently Asked Questions
Last updated: 2026-09-26 ·
Reviewed by Nham Vu