For working electricians
Free electrical calculators, plus quoting built on your real costs
Check conduit fill, size wire and look up ampacity from NEC tables in seconds. Then price the job from your own material and labor costs, not guesses.
The calculators are free and need no account.
- NEC 2026
- No account needed
- Works on your phone
Free calculators
Conduit fill calculator
See how many conductors fit in a conduit and whether the fill is within the NEC limit.
OpenWire size calculator
Pick a conductor size for your load, insulation rating and installation conditions.
OpenAmpacity chart
Look up allowable ampacity by wire size, conductor material and temperature rating.
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Charts and quick answers
Conduit fill charts
Popular conduit sizes
Quotes built on your real costs
We are building a quoting tool around what the job really costs you: your material prices, your labor rates and your markup. Get early access and tell us what you need.
Get early accessFor reference only. Always verify with the NEC edition adopted by your AHJ.