Free electrical planning tools

Check one decision. Plan the whole route.

Use focused calculators to understand voltage drop, conduit fill, and conductor ampacity. Each tool explains its assumptions and keeps the useful result available without signup.

Route performance

Voltage drop calculator

Estimate AC or DC voltage loss from route length, load, conductor size, and installation assumptions.

Open calculator Raceway planning

Conduit fill calculator

Compare conductor area with the modeled fill allowance for EMT or PVC Schedule 40.

Open calculator Conductor sizing

Electrical wire size calculator

Find a preliminary conductor size from load, material, terminals, ambient temperature, and conductor count.

Open calculator

Calculators answer questions. Plans connect the answers.

A wire size can satisfy ampacity and still produce too much voltage drop over a long route. A larger conductor can reduce that drop while consuming more raceway area. These tools separate each relationship so you can learn it clearly. ZapSketch brings them back together around the route drawn on the plan.

Results use a documented NEC 2023 design-aid model and cover only the inputs shown. Confirm the adopted code, equipment requirements, installation details, and field conditions for the project.

Ready to connect the work?

Turn individual checks into a coordinated home-run plan.

Draw routes on the plan, keep length tied to the circuit, and review preliminary conductor, voltage-drop, fill, and material feedback together.

Open ZapSketch and plan a route