TDS Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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A small unit or concentration mistake can move a solution calculation by orders of magnitude. TDS Calculator keeps the relevant quantities visible and applies the configured equation on a consistent basis.

What this calculator does

The TDS Calculator uses Select the method to calculate TDS:, Chloride (Cl⁻), Phosphate (H₂PO₄⁻), Sulfite (SO₃²⁻), and Sulfate (SO₄²⁻). With the bundled default scenario, the primary result is shown as “Total dissolved solids” and the displayed value is 20 mg/L. Supporting outputs include Method. The answer is tied to the exact fields and calculation branch exposed on this page; it does not invent missing sample composition, laboratory conditions, or reference data.

How to use it

The quickest way to avoid an input error is to verify what each field represents before typing a value. This page primarily uses Select the method to calculate TDS:, Chloride (Cl⁻), Phosphate (H₂PO₄⁻), Sulfite (SO₃²⁻), and Sulfate (SO₄²⁻). Keep the chemical basis consistent when you substitute your own data.

How the calculation works

Under the hood, the calculator follows the relationship described in its definition: Estimates total dissolved solids as TDS ≈ conductivity × conversion factor. Any supported unit conversion occurs before the core formula is evaluated, which is why a manual calculation may differ slightly only at the rounding stage.

Worked example

For a reproducible worked check, enter Select the method to calculate TDS: = Water analysis — sum ions; Chloride (Cl⁻) = 1 mg/L; Phosphate (H₂PO₄⁻) = 1 mg/L; Sulfite (SO₃²⁻) = 1 mg/L; Sulfate (SO₄²⁻) = 1 mg/L; Carbonate (CO₃²⁻) = 1 mg/L. The calculator returns 20 mg/L for “Total dissolved solids”. The same run reports Method = ions. This default case is useful for confirming that the expected units, selectors, formula, and sign convention are active before you replace the values with your own data.

How to interpret the result

For TDS Calculator, the primary output should be read in context. Interpret the result within the stated concentration and acid–base model. Real solutions can depart from ideal behavior at high ionic strength or concentration, and measured pH can also depend on temperature and instrument calibration. If the result looks surprising, recheck units, prefixes, signs, chemical formula or species selection, and whether every value belongs to the same sample or condition.

Limitations and practical notes

For TDS Calculator, keep this limitation in mind: Most compact solution calculators use idealized relationships. Activity effects, mixed buffers, polyprotic systems, temperature-dependent constants, or density corrections may require a more detailed model.

Use the TDS Calculator for realistic chemical scenarios and perform a quick reasonableness check. Calculators keep arithmetic consistent, but they cannot determine whether the entered composition, reaction, or experimental setup is physically sensible.