WireGaugeCalc Free calculator · NEC cited · works offline
Horsepower To Fl Amsp
Horsepower to fl amsp is fast with WireGaugeCalc, since the tool reads motor horsepower against voltage and phase to return the full load amps.
You pick the horsepower, the volts, and single or three phase, so the calculator returns the FLA figure.
That gives you the motor current you need to size conductors and overload protection.
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.
How horsepower converts to full load amps
Full load amps fall as voltage rises, so the same horsepower draws fewer amps at 480 volts than at 240 volts.
Three-phase motors draw less current per leg than single-phase at the same horsepower, since the load is split across three lines.
The tool matches the NEC motor full load current tables so the FLA aligns with code values.
What sets full load amps from horsepower
WireGaugeCalc weighs the inputs that convert horsepower to full load amps:
- Motor horsepower rating
- Supply voltage from 120 up to 480
- Single-phase or three-phase service
- NEC table 430.250 values for sizing
- Nameplate amps for the actual running current
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 size wire from the NEC table FLA or the nameplate amps?
Use the NEC table full load current for conductor and protection sizing, not the nameplate amps, per NEC 430.6(A). Confirm the value in the current code tables and with your local authority having jurisdiction.
Why does three-phase show fewer amps than single-phase at the same horsepower?
Three-phase power splits the load across three conductors and includes the square root of three factor, so the current per leg is lower. The calculator applies the correct factor for the phase you select.
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.