WireGaugeCalc Free calculator · NEC cited · works offline
Horsepower To Fla Calculator
Horsepower to fla calculator is fast with WireGaugeCalc, since you pick the horsepower, voltage, and phase and it returns the full load amps for the motor.
It uses the NEC motor FLA tables rather than the nameplate amps, so your branch-circuit sizing follows the code values.
That means you get one clean current figure to drive your wire, breaker, and overload selection.
Open the calculatorEnter any two values and read the rest.
Ohm’s law: V = I × R and P = V × I. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Convert Motor Horsepower To Full Load Amps
Full load amps rise as horsepower rises and fall as voltage rises, so the same motor draws more current at 120V than at 240V.
The calculator reads the matching NEC table value for single-phase or three-phase motors, so you are not guessing from the nameplate.
Why FLA Drives Your Motor Circuit
Full load amps set the rest of the motor circuit, since the NEC scales conductor and protection from this single value:
- Branch-circuit conductors are sized at 125% of the motor FLA.
- Overload protection is set from the nameplate amps and service factor.
- Three-phase motors draw less current per leg than single-phase at the same horsepower.
- Higher voltage on the same horsepower lowers the current draw.
- Use the NEC table FLA for sizing, not the nameplate amps.
One app for every NEC calculation
WireGaugeCalc keeps the calculations you reach for most in one place:
- Voltage drop and wire sizing for any run
- Conduit fill for EMT, PVC, and RMC
- Box fill and junction box sizing
- Ampacity and temperature derating
- Motor circuit and load calculations
- Conduit bend offsets and saddles
Built for the field, works offline
The whole app runs on your phone, so it keeps working in a basement, an attic, or a job site with no signal.
There is no account to create and nothing to load. Open it, run the number, and get back to work.
- No signup and no signal needed
- Answers in a tap, not a spreadsheet
- Same tool on phone, tablet, and desktop
Every result cites the NEC article
Each answer shows the table or formula it came from, so you can check the method and learn the code as you go.
That makes the app useful on the job and during exam prep, since the reasoning is right next to the number.
Switch the code year your job runs on
Jurisdictions adopt the NEC at different times, so you can match the calculation to the code in force:
- NEC 2017, 2020, and 2023 tables
- Copper and aluminum conductors
- 60, 75, and 90 degree C terminations
- Single-phase and three-phase systems
Run the number, then get back to work
Stop flipping through a paper book or hopping between calculator sites. Enter your values, read the code-cited answer, and move on. Free to use, no signup.
Open the calculatorFrequently asked questions
Should I use nameplate amps or NEC table FLA for sizing?
Use the NEC table full load current to size branch-circuit conductors and the short-circuit protection. Use the nameplate amps only to set the overload device.
Why do my full load amps differ from the nameplate?
The NEC tables give standard values that often run slightly higher than a specific nameplate. This is intentional so the wiring covers a range of motors. Verify the final number against the current NEC and your local authority having jurisdiction.
Is WireGaugeCalc free to use?
Yes. Every calculator is free to run with no signup. A paid tier adds saved projects, PDF reports, and extra code years, but the core math stays free.
Does it work without internet?
Yes. The app runs on your device, so it keeps working with no signal on a job site, in a basement, or in an attic.
Are the results code accurate?
Results follow published NEC tables and standard formulas, and each answer shows the article it came from. It is a field aid, not a stamp of approval, so verify against the current code and your local authority before you wire anything.
Which NEC code year does it use?
You can switch between NEC 2017, 2020, and 2023, since jurisdictions adopt the code at different times. Pick the year your job runs on.