How ClayCalc handles formulas, estimates and corrections

1. We label the kind of answer

ClayCalc tools fall into three groups. A direct calculation applies an established equation to measured inputs—for example, water absorption from dry and saturated weights. A conversion expresses the same quantity in another unit. A planning estimate uses geometry, user assumptions or empirical factors to produce a useful range. Drying time, throwing weight and crack risk are planning estimates, not laboratory determinations.

The distinction is important. More decimal places do not improve an estimate when wall thickness, humidity or clay composition is only approximate. Output is rounded to a level that matches the inputs, and estimate pages state the variables that can move the real result.

2. Source order

When a calculator depends on a standard, product ratio or reference chart, we prefer the organization responsible for that information: ASTM for a test scope, Orton for pyrometric cone equivalents, USG for a named plaster product, NIST for units, and the kiln or material manufacturer for equipment-specific data. Industry references such as Digitalfire are used for ceramic terminology and practical test context when no open primary standard describes the studio workflow.

A source link does not mean the source endorses ClayCalc. It tells you which table, definition or method informed the page so you can check the original. If your product data sheet conflicts with a preset, the product data sheet wins.

3. What is tested in software

Each calculator is a deterministic server-side PHP engine. The browser sends the values entered in the form to the calculation endpoint; the response contains the result and any range warnings. Inputs are used for that request and are not written to the application database.

Automated tests cover known input/output examples, invalid ranges, public routes, sitemap coverage and the presence of the input, explanation and tips templates required by every active calculator. These checks catch arithmetic regressions and broken deployments. They do not certify a material, glaze, kiln program or finished object.

4. Coefficients and presets

Some planning tools offer starting values because an empty form is not useful. Presets are clearly editable. A clay shrinkage preset, kiln duty cycle, loss rate or labour allocation is not a universal constant. Replace it with your own measurement as soon as you have one.

We avoid calling an estimate “exact,” “certified” or “food safe.” Food-contact suitability cannot be established from colorant percentage or calculated thermal expansion alone; it depends on the full formulation, firing and appropriate finished-ware testing. Electrical and kiln work must follow the equipment manufacturer and a qualified technician.

5. Editorial review

ClayCalc is an independent calculator project. Pages are published under “ClayCalc Editorial” rather than a fabricated individual expert profile. The project does not claim laboratory accreditation. A page is ready for publication when it explains its inputs, shows the equation or decision model, includes a worked example where useful, states its limits, links to the relevant source and connects to the next practical step.

Generated text is not treated as evidence. Technical claims must be traceable to a source or presented as an explicit assumption. Repetitive filler is removed even when doing so makes a page shorter.

6. Corrections

A useful correction contains the calculator URL, the values entered, the result received, the result expected, units, and a source or repeatable measurement. That is enough to reproduce the issue without receiving a studio notebook or personal data. Corrections are prioritized when they affect safety, reverse the direction of advice, or produce a materially wrong number.

Until a public contact inbox is added, reproducible corrections can be submitted through the contact channel associated with the ClayCalc domain registration or hosting account. A visible project email should be added only when it is monitored; we do not publish a decorative address that no one reads.

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