WireGaugeCalc Free calculator · NEC cited · works offline
10 Ohm Resistor Voltage Drop Calculator
10 ohm resistor voltage drop calculator is quick with WireGaugeCalc, since it multiplies the current by the 10 ohm resistance to give the voltage dropped across the part.
You enter the current in amps, and the tool returns the volts lost across the resistor using Ohm's law, V equals I times R.
That means you can check a series circuit value in seconds instead of doing the math on paper.
Open the calculatorUses Vd = (phase factor × K × I × L) / circular mils, K = 12.9 copper, 21.2 aluminum. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Ohm's law and the 10 ohm drop
Voltage drop equals current times resistance, so 1 amp through a 10 ohm resistor drops 10 volts and 0.5 amp drops 5 volts.
Power burned in the resistor equals current squared times resistance, so the same calculator tells you the watts the part has to handle.
Since the resistance is fixed at 10 ohms, the drop scales straight with the current you push through it.
What the voltage drop calculation returns
Give it the current and it works the Ohm's law math for you:
- Voltage drop in volts across the 10 ohm resistor
- Power dissipated in watts at that current
- Remaining voltage if you enter the source voltage
- Current solved back if you enter the drop instead
- Clear units so series values add up correctly
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
How much voltage drops across a 10 ohm resistor at 2 amps?
By Ohm's law, voltage drop equals current times resistance, so 2 amps times 10 ohms is 20 volts. The calculator returns this directly when you enter the current.
How do I find the power rating I need for the resistor?
Power equals current squared times resistance, so 1 amp through 10 ohms dissipates 10 watts. Pick a resistor rated above that figure so it does not overheat.
Is this the same as conductor voltage drop on a wire run?
The math is the same Ohm's law, but a long wire run uses the cable resistance and the round trip length instead of a single part. For branch circuit limits, verify 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.