About AllJobsCalc

AllJobsCalc is a small set of free, fast, no-signup calculators for electricians, HVAC technicians, plumbers, carpenters, roofers, welders, and machinists. It exists because most "free" calculator tools online are either locked behind account creation, cluttered with pop-ups, or vague about where their numbers actually come from.

Every calculator here is built from a specific, cited code section or standard reference table — NEC Table 310.16 for ampacity, NEC Chapter 9 for conduit and box fill, IPC drainage fixture-unit tables for pipe sizing, IRC stair provisions, and widely used industry reference charts. Each calculator page explains the formula or table it uses so you can sanity-check it yourself, not just trust a black box.

See the sources and checks for every calculator, and our corrections log →

Who runs AllJobsCalc

AllJobsCalc is built and maintained by Rizon Lab (rizonlab.com), a small web studio in Preveza, Greece, run as a sole proprietorship. Rizon Lab writes the calculators and guides, checks them against their sources and keeps them up to date. The site is paid for by advertising; nothing in a calculator or guide is sponsored.

How the numbers are checked

Each calculator is built from a named code section, regulation or published table, and its formulas are covered by automated tests that reproduce worked examples from those sources (over 140 tests as of October 2026). When a code table or source changes, the calculator, its tests and the Sources & methodology page are updated together and the change is logged with its date. The guides are written from the same sources, and their tables are generated by the calculators' own code, so a guide and its calculator cannot disagree.

See the dated list of updates →

What this is not

This is not a substitute for a licensed professional, a stamped engineering load calculation, or your local Authority Having Jurisdiction (AHJ). Code editions and local amendments vary by location and change over time. Treat every result here as a planning estimate and starting point — always verify against the current code adopted in your area before design, bidding, or installation. Full details in the disclaimer.

No accounts, no clutter

There's nothing to sign up for. Calculators run entirely in your browser — inputs aren't sent to a server or stored anywhere. See the privacy policy for specifics.

Report an error

Spotted an error or have a question? Email us at contact@alljobscalc.com. Every message is read, and corrections are made and noted.