I built a small browser calculator inside an existing insurance-agency cost guide. Four blank inputs cover total staff minutes, hourly staff cost, additional per-batch tool cost and the number of checked results. It shows staff cost, batch cost and cost per checked result, with the arithmetic and rounding explained.

Blank is not zero. Explicit zeros are allowed, checked-result counts must be positive whole numbers, and editing an input clears a stale result. The calculation stays in the browser, with no calculator input submission or storage. Existing site analytics still runs. Without JavaScript, calculator controls stay disabled and the original worksheet and worked example remain available.

The fictional arithmetic example uses 90 minutes at 30 per hour, 1 in tool cost and 10 checked results: batch cost 46.00 and cost per checked result 4.60, in the reader's chosen currency. Include preparation, review, corrections and filing in staff time. Setup and monthly upkeep are excluded and need separate treatment.

Prepared with AI assistance alongside my Cirlet AI and automation service. This is a free educational tool, not a customer result, measured savings, a quote or a quality check.