TDS Calculator

The TDS Calculator is a completely free online tool that instantly calculates Total Dissolved Solids (TDS in mg/L or ppm) from electrical conductivity (EC) using any conversion factor k — or directly sums cations and anions from a full water chemistry analysis — with zero registration, zero limits, and zero ads.

Choose your method, enter EC (µS/cm) and k (0.5–0.8; default 0.67 for most natural waters), or input individual ion concentrations (mg/L); the tool applies the exact standard formulas in under one second:

• From conductivity: TDS (mg/L) = k × EC (µS/cm)

• From ions: TDS (mg/L) = Σ cations + Σ anions

Built for chemistry students, teachers, environmental scientists, and lab professionals evaluating drinking water, reverse osmosis rejection rates, hydroponics, aquariums, or wastewater, this mobile-first calculator delivers textbook-accurate results with automatic unit conversion (µS/cm ↔ mS/cm), optional ion-balance check, and step-by-step explanations. Fast loading, clean interface, full privacy, and no data collection — just reliable calculations you can trust on any device. Start measuring TDS now.

Information & User Guide

  • What is TDS Calculator?
  • What is TDS Calculator?
  • Formula & Equations Used
  • Real-Life Use Cases
  • Fun Facts
  • Related Calculators
  • How to Use
  • Step-by-Step Worked Example
  • Why Use This Calculator?
  • Who Should Use This Calculator?
  • Common Mistakes to Avoid
  • Calculator Limitations
  • Pro Tips & Tricks
  • FAQs

What is TDS Calculator?

What is a TDS Calculator?

A TDS Calculator is a tool used to measure or estimate the Total Dissolved Solids (TDS) present in a liquid, usually water. TDS refers to the combined content of all inorganic and organic substances such as salts, minerals, and metals dissolved in water.

This calculator allows users to determine water quality quickly and make informed decisions about water treatment, purification, and consumption.

What is TDS Calculator?

What is the Related Concept?

The related concept is Total Dissolved Solids (TDS), a key indicator of water quality.

Key points:

  • TDS is measured in mg/L (ppm).
  • Higher TDS levels can affect taste, health, and appliance efficiency.
  • TDS can originate from natural minerals, industrial pollutants, or agricultural runoff.

Understanding TDS is critical for safe drinking water, aquariums, hydroponics, and industrial applications.

Formula & Equations Used

Formula & Equations Used

The TDS in water can be calculated using the TDS formula:

TDS (mg/L) = EC (µS/cm) × Conversion Factor (0.5–0.9)
  • EC = Electrical Conductivity of water
  • Conversion Factor = Depends on ion composition, typically 0.64 for standard water

Highlighted Formula Frame

TDS (mg/L) = EC (µS/cm) × Conversion Factor

This formula helps convert electrical conductivity readings into TDS concentration efficiently.

Real-Life Use Cases

  • Checking home tap or bottled water TDS
  • Maintaining healthy aquarium conditions
  • Monitoring water in hydroponic farming
  • Evaluating water quality in industrial processes
  • Assessing municipal water treatment efficiency
  • Monitoring TDS ensures safe consumption, optimal growth, and machinery longevity.

Fun Facts

  • TDS levels affect water taste and clarity; very low or high TDS can be unpleasant.
  • Distilled water has TDS close to 0 mg/L, but may taste flat.
  • Mineral-rich water can have TDS over 500 mg/L but may be beneficial for health.
  • TDS measurement is used in aquaculture, brewing, and hydroponics.
  • Monitoring TDS is a cost-effective way to assess water pollution.

Related Calculators

How to Use

  1. Measure the electrical conductivity (EC) of your water sample.
  2. Enter the EC value into the calculator.
  3. Select or enter the conversion factor (default = 0.64).
  4. Click Calculate to get the TDS value in mg/L.
  5. The calculator provides instant and accurate results to assess water quality.

Step-by-Step Worked Example

Step-by-Step Worked Example

Problem: A water sample has EC = 500 µS/cm. Use a conversion factor of 0.64 to calculate TDS.

Step 1: Apply the formula

TDS = EC × Conversion Factor

Step 2: Insert values

TDS = 500 × 0.64 = 320 mg/L

Step 3: Interpret result

The water has TDS = 320 mg/L, which is within the safe range for drinking water according to WHO guidelines.

Why Use This Calculator?

  • Quickly estimate water quality
  • Monitor water purification system efficiency
  • Assess suitability for drinking, aquaculture, and irrigation
  • Identify changes in water composition over time
  • Save time compared to manual testing methods
  • It’s an essential tool for homeowners, lab technicians, and environmental engineers.

Who Should Use This Calculator?

  • Homeowners checking drinking water quality
  • Aquarists maintaining aquarium water health
  • Environmental engineers and researchers
  • Farmers using water for irrigation
  • Industry professionals monitoring water in manufacturing
  • Anyone concerned with water quality and dissolved solids content will benefit.

Common Mistakes to Avoid

  • Using an incorrect conversion factor
  • Measuring EC with contaminated probes
  • Ignoring temperature effects on conductivity
  • Assuming low TDS automatically means safe water
  • Forgetting to calibrate meters before measurement
  • Proper technique ensures accurate TDS readings.

Calculator Limitations

  • Assumes standard water ion composition
  • May not reflect organic contaminants
  • Temperature variations can slightly affect EC readings
  • Cannot replace detailed lab water analysis
  • Does not measure individual ions, only total dissolved solids
  • It’s a quick estimation tool, not a comprehensive water test.

Pro Tips & Tricks

  • Use clean, calibrated EC meters for precise readings
  • Repeat measurements for consistency
  • Compare TDS readings before and after water treatment
  • Know the typical safe range for your application (drinking, aquarium, irrigation)
  • Combine TDS with pH and hardness checks for complete water quality assessment

FAQs

According to WHO, 300–600 mg/L is ideal, but up to 1000 mg/L is generally acceptable.
Low TDS may taste flat, while high TDS can taste salty, bitter, or metallic.
Yes, sudden increases in TDS can indicate dissolved pollutants or salts in water.
TDS is directly proportional to EC. Higher EC indicates higher dissolved solids.
Yes, but the conversion factor must be adjusted due to high salt content.
No. Low TDS may lack minerals or still contain harmful microorganisms.
Monthly checks are recommended, or whenever you notice taste or odor changes.
Yes, high TDS can lead to scale formation and damage pipes, boilers, and machinery.
TDS is useful but should be combined with pH, ammonia, nitrite, and nitrate checks.
Higher temperatures increase conductivity, so TDS readings may slightly rise with warmer water.