Major Oxide Normalization Calculator
Rescale a whole-rock or XRF major-oxide analysis to a 100% or volatile-free (LOI) basis, with a side-by-side original vs normalised table — a reporting-basis change, never an accuracy claim.
Oxide analysis (wt%)
| Oxide | wt% | |
|---|---|---|
Normalisation changes the reporting basis — it does not improve analytical accuracy. Blank means missing; 0 means explicitly zero.
Normalised result
Runs entirely in your browser. Your assay data is not uploaded or stored by Zerdly.
- Enter at least one oxide value.
Assumptions & basis
- Basis: Changes the reporting basis; does not improve accuracy (derived)
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 each major oxide in wt% (load the common whole-rock set with one click).
- Choose the basis: renormalise the measured set to 100%, or remove LOI for a volatile-free basis.
- Read the normalised value for each oxide, the scale factor and how far the original sum sat from 100%.
How it works
Renormalising to 100% simply scales every oxide by 100 ÷ (sum of the selected oxides), so norm_i = ox_i / Σox × 100. This forces the reported set to total 100% without changing the relative proportions. It does NOT improve analytical accuracy — it only changes the reporting basis, which matters when comparing analyses or feeding a classification diagram.
The volatile-free basis instead removes loss on ignition: vf_i = ox_i × 100 / (100 − LOI). This assumes the LOI is entirely volatile loss, which is a deliberate choice you confirm — the tool will not assume LOI equals the missing total. An optional final renormalisation to 100% is offered as a separate, explicit second step so two transformations are never hidden inside one result.
Worked example
A basalt analysis summing to 98.46%. A major-oxide set totals 98.46 wt%. Renormalising to 100% multiplies every oxide by 100 ÷ 98.46 = 1.01564, so SiO₂ of 49.20% becomes 49.97% and the set now totals exactly 100%. The relative proportions are unchanged — only the basis moved.
Common mistakes
- Believing normalisation improves accuracy. It rescales the basis; it cannot fix a poor analysis.
- Mixing FeO and Fe₂O₃ without understanding the iron basis you are reporting.
- Treating LOI as the whole missing total when renormalising to 100% — the two bases are different.
Frequently asked questions
What is the difference between renormalising to 100% and removing LOI?
Renormalising to 100% scales the measured oxides so they total 100. A volatile-free basis first divides out the LOI (100/(100−LOI)); it assumes the LOI is volatile loss. They give different numbers and answer different questions.
Why doesn't the total always start at 100?
Real analyses rarely sum to exactly 100% because of LOI, unanalysed components and analytical error. The tool shows the original sum and the difference from 100 so you can judge the data before normalising.
Related tools
- Elements to Oxide Calculator
- Loss on Ignition (LOI) Calculator
- Assay Unit Converter
- XRF / Assay Total Checker
- Oxide Moles & Cations Calculator
- Mineral Formula / APFU Calculator
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Cite this tool
Zerdly. (2026). Major Oxide Normalization Calculator. Retrieved from https://www.zerdly.com/tools/major-oxide-normalization-calculator/
Tip: Enter any known values to calculate the remaining results.
All calculations run in your browser. Your inputs are never saved or transmitted.