Field Guides

Every guide here does the same job: take one piece of business math that operators get burned by, explain it in plain English, work through it with real numbers, and point to the calculator that runs it. No filler, no theory for theory's sake — each guide exists because getting this particular calculation wrong costs real money.

Contractors & Trades

Calculators for these guides live in the Contractors & Trades hub.

Small Business Core

Calculators for these guides live in the Small Business hub.

Pay & Income

How Guides Are Written

Guides follow the same standards as our calculators: formulas shown, assumptions stated, at least one fully worked numeric example, and an honest section on where the math goes wrong. Contractor guides are framed and reviewed by Gerald G., founder of CalcAuthority, drawing on his background as a journeyman cabinet installer, subcontractor, and contracting business owner. See the Methodology page for the full editorial standard.

Educational content only. Guides explain math and concepts for planning purposes. They are not financial, tax, legal, or accounting advice. See our Financial Disclaimer.