Analytical Tool · Saltysoil Reference Bench

TDS & EC Conversion Calculator

Client-side scientific instrument for converting electrical conductivity (µS/cm, mS/cm) and total dissolved solids (ppm) with transparent ionic conversion factors.

Analytical Instrument · Offline Computation

TDS & EC Conversion Calculator

Convert electrical conductivity and total dissolved solids with flexible conversion factors.

Conversion Factor (TDS / EC µS/cm)
Calculated Output
640 ppm

1,000 µS/cm × 0.64 = 640 ppm

EC (µS/cm) 1,000
EC (mS/cm) 1
Estimated TDS (ppm) 640
Scientific Caveat: TDS-to-EC conversion is inherently approximate, not a universal physical constant. The true ratio varies according to the specific ionic composition, ion valence, temperature compensation, and dissolved organic or mineral species in each water or soil extract sample.

Conversion Equations

TDS (ppm) = EC (µS/cm) × Conversion Factor

EC (µS/cm) = TDS (ppm) ÷ Conversion Factor

1 mS/cm = 1,000 µS/cm

Where electrical conductivity (EC) measures the capacity of dissolved ions to conduct electrical current (standardized to 25 °C), and total dissolved solids (TDS) expresses estimated total mass concentration in mg/L (numerically equivalent to parts per million in dilute aqueous solutions).

Common Conversion Factor Guidance

Factor Reference Basis Typical Context
0.50 Sodium Chloride (NaCl) Standard handheld meters calibrated to NaCl solutions and brackish chloride waters.
0.64 442 Natural Water Mix Approximates mixed freshwater (sulfates, bicarbonates, chlorides); commonly ranges 0.64–0.65.
0.70 Potassium Chloride (KCl) Nutrient-rich soil extracts, fertigation monitoring, and concentrated mineral solutions.

Worked Example Calculations

Select any row to populate the calculator above for verification:

Scenario Input Factor Output Load
Freshwater irrigation supply 850 µS/cm 0.64 (442) 544 ppm
Moderately saline soil extract 2.4 mS/cm 0.70 (KCl) 1,680 ppm
NaCl calibration check 500 ppm 0.50 (NaCl) 1,000 µS/cm (1 mS/cm)
REFERENCE /

General Soil Saturated Paste (ECe) Salinity Classes

Reference context based on classical agricultural salinity classification of saturated soil paste extracts at 25 °C (plant responses still vary widely by species and ion toxicity):

Salinity Classification ECe (mS/cm or dS/m) ECe (µS/cm) General Crop Response Note
Non-saline 0 – 2.0 0 – 2,000 Salinity effects mostly negligible for typical crops.
Very slightly saline 2.0 – 4.0 2,000 – 4,000 Yields of highly sensitive crops may be restricted.
Moderately saline 4.0 – 8.0 4,000 – 8,000 Yields of many standard crops restricted; salt-tolerant varieties preferred.
Strongly saline 8.0 – 16.0 8,000 – 16,000 Only tolerant crops yield satisfactorily.
Very strongly saline > 16.0 > 16,000 Only specialized halophytic species tolerate sustained exposure.