TDS Calculator - Total Dissolved Solids

Your details

EC meter mode converts electrical conductivity to TDS using an empirical factor. Ion mode sums all dissolved ions from a lab report.
Reading from your EC or TDS meter. Most pocket TDS meters measure EC internally then multiply by a built-in factor.
µS/cm
Empirical factor that converts EC to TDS. It depends on the dominant salt type. Most meters use 0.64 or 0.67 internally.
Total Dissolved SolidsAcceptable
335mg/L (ppm)

Sum of all dissolved ions in water (1 mg/L = 1 ppm for water)

EC estimate500µS/cm
Drinking-water qualityAcceptable (335 ppm)
Salinity estimate0.335ppt
335 ppm
Excellent<50Good50-150Fair150-300Acceptable300-500Poor500-1000Very poor1000+

TDS is 335 mg/L (ppm) - Acceptable quality for drinking water.

  • The US EPA secondary standard sets 500 mg/L as the upper acceptable limit for taste and aesthetic quality in drinking water. This sample is at or near that boundary.
  • Estimated electrical conductivity is 500 µS/cm. A standard TDS meter converts EC using a built-in factor of 0.64-0.67.

Next stepSuitable for most household uses. For brewing specialty coffee or tea, some roasters prefer 50-150 ppm; consider a filter or blending with lower-TDS water.

 = Powered by OnlyCalculators