Decisions for the trades, not just numbers.
Put in your conditions and get a real recommendation: the size or the option that makes sense, why it makes sense, the alternatives, the tradeoffs, and a record you can copy, print, or share. It runs in your browser. No account, no sign-up.
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Browse all engines → Electrical Wire Size and Voltage Drop Pick a conductor size and material for a run, and know whether ampacity or voltage drop is really driving it. Electrical Breaker and OCPD Sizing Size the breaker for a load and its conductor, and see what the code rules actually require. Electrical Voltage Drop Remedy Your run drops too much voltage. See the ways to fix it and which one makes sense. Electrical Conduit Fill Pick a conduit size for a bundle of conductors and see how much room is left for future pulls. Electrical Box Fill Figure the required box volume for your conductors and devices, and pick a box that fits. Plumbing Water Pipe Sizing Size a water supply line so the far fixture still gets the pressure and flow it needs. Plumbing Drain Sizing Add up the fixtures and size a drain branch or building drain, with the water-closet and slope rules built in. Plumbing Water Heater Sizing Decide between a tank and a tankless water heater for your peak demand and climate. Plumbing Gas Pipe Sizing Size a natural gas line for the appliance load and run, with a plain warning that gas work is for a licensed pro. HVAC HVAC Load Sanity Check Sanity-check a quoted air conditioner or furnace size before you commit, and know when you need a real Manual J. HVAC Duct Sizing Size a round duct for an airflow and see the velocity, with a quieter size up. Concrete Concrete Volume and Order Work out how much concrete a pour needs, then decide whether to bag it or order ready-mix.
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Plumbing Drain and vent sizing on the way
HVAC Duct size (friction rate) on the way
Solar String sizing on the way
Why a workbench and not a calculator
Most trade calculators hand you a number and stop. A real job needs a decision. Which wire, which pipe, order the ready-mix or bag it, and why. TradesWorkbench is built around that second question. Every tool shows the reasoning and the tradeoffs so you can stand behind the call and explain it to whoever asks.
These are planning tools. They do not replace a licensed professional, a permit, or an inspection, and they do not certify code compliance.