WireGaugeCalc Free calculator · NEC cited · works offline
1.25hp to Amps
1.25hp to amps is quick with WireGaugeCalc, which reads the NEC full-load current near the listed motor sizes for your voltage and phase.
You enter the horsepower, voltage, and phase, so the calculator returns the amps used for sizing.
That number is what you carry into conductor and overload sizing.
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.
Converting 1.25 Hp to Motor Amps
The NEC lists motor full-load current by horsepower in Tables 430.248 and 430.250, since real amps depend on voltage and phase, not horsepower alone.
Because 1.25 hp sits between 1 hp and 1.5 hp, the calculator references the nearest listed values so the result matches the table figures.
Conductor ampacity is sized at 125% of FLA because the motor is treated as a continuous load.
What the 1.25 Hp Conversion Shows
Enter the motor details and read the amps you need:
- FLA at 115V and 230V single phase
- FLA at 200V, 230V, and 460V three phase
- 125% of FLA for conductor sizing
- A baseline for overload protection
- Amps shown clearly for the wire size step
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
Why not just use a horsepower-to-amp formula?
A raw formula ignores motor efficiency and power factor, while the NEC tables give standardized full-load values for sizing. Verify the result against the current NEC and your local authority having jurisdiction.
Does voltage change the amps for 1.25 hp?
Yes, amps fall as voltage rises since power stays roughly the same, so a 230V motor draws fewer amps than a 115V one. The calculator updates the FLA when you change the voltage.
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.