Zerdly

Assay Unit Converter

Convert mass-based assay concentration units — wt%, ppm, ppb, g/t, mg/kg, µg/g and more — without changing the chemical species, with a clear equivalence ladder.

100% FreeRuns in your browserBasic
How to use this calculator

Convert

Mass-based solid assay. This is not mg/L — that needs a solution density and is a different conversion.

Result

Runs entirely in your browser. Your assay data is not uploaded or stored by Zerdly.

More needed
  • Enter a value and choose valid units.
Assumptions & basis
  • Basis: Mass-based solid assay (not mg/L solution) (user)

Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.

How to use this calculator

  1. Enter a value and choose the input and output units (or use a quick chip like % → ppm).
  2. Read the converted value plus the common equivalents (wt%, ppm, g/t).
  3. Use the swap button to reverse the conversion.

How it works

For a solid, mass-based assay the units are all fixed multiples of a mass fraction: 1 wt% = 10,000 ppm, 1 ppm = 1 mg/kg = 1 µg/g = 1 g/t, 1 ppb = 0.001 ppm, and 1 mg/g = 1,000 ppm = 0.1 wt%. The tool converts to a mass fraction internally and back out to your chosen unit, so every result is an exact ratio.

This is deliberately kept separate from mg/L. Converting a mass-per-mass unit (ppm) to a mass-per-volume unit (mg/L) needs the solution or bulk density and a stated basis — it is a different calculation, so it is not silently mixed in here.

Worked example

1.2 wt% to ppm. 1.2 wt% × 10,000 = 12,000 ppm, which is also 12,000 g/t and 12,000 mg/kg for a mass-based solid assay.

Common mistakes

  • Treating ppm as mg/L — that equivalence needs a density and basis.
  • Mixing mass-based and solution units in one step.
  • Assuming g/t differs from ppm for a solid assay; they are identical by mass.

Frequently asked questions

Is ppm the same as g/t?

For a mass-based solid assay, yes: 1 ppm = 1 g/t = 1 mg/kg = 1 µg/g. They are all one part per million by mass.

Why isn't mg/L included?

mg/L is mass per volume, so converting to it from ppm requires the solution density and basis. That is a separate mode, kept out of the mass-based ladder to avoid a hidden assumption.

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Cite this tool

Zerdly. (2026). Assay Unit Converter. Retrieved from https://www.zerdly.com/tools/assay-unit-converter/

Tip: Enter any known values to calculate the remaining results.

All calculations run in your browser. Your inputs are never saved or transmitted.