TDS Calculator

Calculate Total Dissolved Solids (TDS) in Water

Enter your water sample's electrical conductivity (EC) or mass/volume to determine the TDS (mg/L or ppm). Useful for water quality, chemistry, hydroponics, and more.

TDS Calculator Examples

See how to use the TDS Calculator with real-world scenarios.

Drinking Water (EC Method)

EC Method

Calculate TDS for tap water with EC 500 µS/cm and factor 0.64.

Calculation Method: EC & Factor

EC Value: 500

EC Unit: µS/cm

Conversion Factor: 0.64

Result Unit: mg/L

Hydroponics Nutrient Solution

EC Method

TDS for hydroponic solution: EC 1.2 mS/cm, factor 0.5, result in ppm.

Calculation Method: EC & Factor

EC Value: 1.2

EC Unit: mS/cm

Conversion Factor: 0.5

Result Unit: ppm

Lab Sample (Mass/Volume)

Mass Method

TDS for a sample with 120 mg solids in 1.5 L water.

Calculation Method: Mass & Volume

Total Mass (mg): 120 mg

Sample Volume (L): 1.5 L

Result Unit: mg/L

Aquarium Water

Mass Method

TDS for aquarium: 80 mg solids in 0.25 L, result in ppm.

Calculation Method: Mass & Volume

Total Mass (mg): 80 mg

Sample Volume (L): 0.25 L

Result Unit: ppm

Other Titles
Understanding Total Dissolved Solids (TDS): A Comprehensive Guide
Everything you need to know about TDS, its calculation, and real-world applications.

What is Total Dissolved Solids (TDS)?

  • Definition of TDS
  • Why TDS Matters in Water Quality
  • Common Sources of Dissolved Solids
Total Dissolved Solids (TDS) refers to the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized, or micro-granular suspended form. TDS is a key indicator of water quality in chemistry, environmental science, and industry.
TDS and Water Purity

TDS in Everyday Water Samples

  • Tap water typically has a TDS between 100-500 mg/L.
  • Distilled water has a TDS close to 0 mg/L.

Step-by-Step Guide to Using the TDS Calculator

  • Choosing the Calculation Method
  • Entering EC or Mass/Volume
  • Interpreting the Results
To use the TDS Calculator, select your preferred calculation method: EC & Factor or Mass & Volume. Enter the required values and select the result unit. The calculator will instantly provide the TDS value and the formula used.
Quick and Accurate TDS Calculation

Sample Calculations

  • For EC 500 µS/cm and factor 0.64, TDS = 320 mg/L.
  • For 120 mg solids in 1.5 L, TDS = 80 mg/L.

Real-World Applications of TDS Calculation

  • Drinking Water Safety
  • Hydroponics and Agriculture
  • Aquarium and Environmental Monitoring
TDS measurement is essential in many fields: ensuring safe drinking water, optimizing hydroponic nutrient solutions, maintaining aquarium health, and monitoring environmental water sources.
Why TDS Matters in Practice

TDS in Action

  • Hydroponic growers use TDS to adjust nutrient concentrations.
  • Municipalities monitor TDS for water safety compliance.

Common Misconceptions and Correct Methods

  • TDS vs. EC: Not the Same
  • Conversion Factor Variability
  • TDS and Water Taste
Many believe TDS and EC are interchangeable, but they measure different properties. The conversion factor depends on the dissolved substances. TDS also affects water taste, but high TDS does not always mean unsafe water.
Avoiding Calculation Mistakes

Misconceptions Explained

  • Using 0.5 as a factor for NaCl solutions, 0.7 for KCl.
  • TDS meters may use a fixed factor, but actual TDS can vary.

Mathematical Derivation and Examples

  • TDS from EC: The Formula
  • TDS from Mass/Volume
  • Unit Conversions and Practical Tips
TDS (mg/L) = EC (µS/cm) × Factor. For EC in mS/cm, first convert to µS/cm (1 mS/cm = 1000 µS/cm). Alternatively, TDS (mg/L) = Mass (mg) / Volume (L). For most water samples, 1 mg/L ≈ 1 ppm.
Formulas and Example Calculations

Mathematical Examples

  • EC = 1.2 mS/cm, Factor = 0.5: TDS = 1.2 × 1000 × 0.5 = 600 mg/L.
  • Mass = 80 mg, Volume = 0.25 L: TDS = 80 / 0.25 = 320 mg/L.