Elements to Oxide Calculator

How to use this calculator

1. Pick a direction: Element → Oxide, or Oxide → Element.
2. Enter your value and its unit (wt%, ppm, g/t, ppb…). The chemical factor is the same in any concentration unit.
3. Search the library for your conversion (by element, symbol, oxide formula or alias), or switch to Custom formula for any valid oxide.
4. Read the result, the factor used and the reverse factor; open Advanced details for the molar mass and the working.
5. For many rows, open the Batch converter and paste a sample,value,unit,conversion table.

How it works

The conversion factor comes from atomic weights and the oxide formula, not a hand-typed table: factor = molar mass of the oxide ÷ (number of target-element atoms in the oxide × atomic weight of the element). The oxide equivalent is your value × factor; the element equivalent is the oxide value ÷ factor.

Because the factor is a mass ratio, it is independent of the concentration unit — 40 wt% Fe and 40 ppm Fe both multiply by 1.4297 to give the Fe₂O₃ equivalent in the same unit. An optional output-unit selector then re-expresses the result (e.g. wt% → ppm × 10,000).

Every curated factor in this tool is computed from the stored atomic weights and cross-checked against published reference factors, so the library and any custom formula stay internally consistent.

Worked example

Iron to Fe₂O₃ at 40 wt%. Fe₂O₃ molar mass = (2 × 55.845) + (3 × 15.999) = 159.687 g/mol; the iron inside it is 2 × 55.845 = 111.690. Factor = 159.687 ÷ 111.690 = 1.4297, so 40.00 wt% Fe = 40.00 × 1.4297 = 57.19 wt% Fe₂O₃ (reverse factor 0.6994).

Common mistakes

• Assuming one oxide per element. Iron alone is reported as FeO, Fe₂O₃, Fe₃O₄ or total iron as Fe₂O₃(T); manganese, cerium, praseodymium, terbium and uranium also have multiple conventions. Match your lab/reporting basis — the tool flags these with a ⚠.
• Reading an oxide equivalent as proof of mineralogy. The result is a stoichiometric equivalent by formula mass; it does not show the sample physically contains that oxide.
• Oxide totals over 100 wt% usually mean the input wasn't a whole-sample percentage, or a unit mismatch — the tool warns when a wt% oxide result exceeds 100.

Frequently asked questions