How We Verify Our Calculators
A calculator is only as good as the numbers behind it. A wrong bed temperature, a misread datasheet or an out-of-date electricity rate leads to failed prints and mispriced jobs, so we hold every figure on this site to one rule: trace it to the source, never guess. This page explains what that means in practice.
The process
- ✓Material figures such as nozzle and bed temperatures, densities and shrinkage rates are taken from the filament and printer manufacturers’ own datasheets (Prusa, Polymaker, Sovol, E3D, Formlabs and others), not from forum rules of thumb.
- ✓Thread, bolt-hole, nut-trap and tolerance calculators follow the published ISO standards they name, including ISO 286, ISO 724 and ISO 4032, with printing allowances stated separately from the standard dimensions.
- ✓Slicer and firmware behaviour is checked against the documentation and defaults of Cura, PrusaSlicer, Marlin and Klipper, so settings advice matches what the software actually does.
- ✓Belt, pulley and other community-standard parts use the published open RepRap specifications, such as the canonical GT2 pulley dimensions.
- ✓UK electricity running costs use the current Ofgem price cap rate, updated when the cap changes.
- ✓Every calculator is tested against hand-worked examples with expected answers derived independently from the source, and the whole site is re-checked adversarially: auditors re-derive results from scratch and when a check disagrees with the code, we fix the code.
- ✓Errors reported through the feedback buttons are investigated against the original source, fixed, and re-verified before the fix goes live, and content is reviewed when the underlying datasheets, standards or rates are updated.
Verified, not guaranteed
These calculators give estimates and starting points, not professional advice. Real results depend on your specific printer, filament batch, slicer version and environment, so always run test prints and confirm filament quantities and prices with your supplier before committing to a large job. For printed parts that carry load or serve a safety function, have the design checked by a qualified engineer.
Spotted an error?
Every calculator page has feedback buttons. If a figure looks wrong, tell us what you entered and what you expected: we investigate against the original source, fix anything that fails the check, and re-verify before the correction goes live.