PPM Percent Converter

Parts per million is a mass fraction: how many grams of the element sit in one million grams (one tonne) of material.

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Enter Values

Grade in ppm (parts per million)

Grade in percent (%)

Enter your values and press Calculate to see results.

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

Enter a value in ONE field only — either ppm or percent — and leave the other blank; the converter fills in the missing one.
Read the grade in both units plus the equivalent grade in g/t (grams per tonne), which equals the ppm value by mass.
Use ppm/g-t for trace-level grades (gold, silver, trace elements) and percent for base metals and major oxides.

How it works

Parts per million is a mass fraction: how many grams of the element sit in one million grams (one tonne) of material. Percent is parts per hundred. Because a million is ten thousand hundreds, 1 % = 10,000 ppm. So percent = ppm ÷ 10,000 and ppm = percent × 10,000 — a straight linear conversion with no other assumptions.

This is why 1 ppm = 1 g/t by mass: one gram in one tonne (1,000,000 g) is one part per million, so the ppm figure and the g/t figure are numerically identical for solid mass fractions. That equivalence lets you move between assay units (g/t for precious/trace metals, % for base metals and oxides) without re-weighing. Note this is mass-based; ppm quoted by volume for gases or solutions uses a different basis and is not covered here.

Worked example

Convert a 25,000 ppm assay to percent. A grade-control assay returns 25,000 ppm. Enter 25000 in the ppm field and leave percent blank. percent = ppm ÷ 10,000 = 25,000 ÷ 10,000 = 2.5 %. The tool also reports the equivalent grade by mass as 25,000 g/t (since 1 ppm = 1 g/t). Reversing it: entering 0.85 % returns 8,500 ppm (0.85 × 10,000).

Common mistakes

Filling in both fields, or neither — enter exactly one value and let the tool compute the other.
Dividing or multiplying by 1,000 or 100 instead of 10,000. The correct factor between % and ppm is 10,000 (1 % = 10,000 ppm).
Assuming ppm = g/t always. It holds for solid mass fractions (ore, assays), but not for ppm-by-volume used with gases or liquids, where density and molar mass matter.

Frequently asked questions

How many ppm are in 1 percent?

Exactly 10,000 ppm. To convert any percent to ppm, multiply by 10,000 (e.g. 0.5 % = 5,000 ppm). To go the other way, divide ppm by 10,000.

Is ppm the same as grams per tonne (g/t)?

For solid mass fractions, yes: 1 ppm = 1 g/t, because one gram in a 1,000,000-gram tonne is one part per million. So a 3 g/t gold assay is 3 ppm. This does not apply to ppm-by-volume for gases or solutions.

When would I use ppm/g-t versus percent for a grade?

Trace and precious-metal grades (gold, silver, PGEs, trace elements) are usually reported in ppm or g/t because the values are tiny; base-metal grades and major oxides (copper, zinc, iron, SiO₂) are reported in percent. This converter moves between the two.

Does this account for recovery, dilution or specific gravity?

No. It is a pure unit conversion of a single grade figure. Recovery, dilution and tonnage factors are separate steps handled by dedicated grade-control and reconciliation tools.

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

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