RV Electrical Load Calculator
Estimate how many watts and amps your RV appliances use at the same time. Compare your estimated load with a 15A, 20A, 30A or 50A shore-power hookup, or an inverter/generator rating.
3. Your RV Electrical Load Results
* Amps are calculated as total watts ÷ selected nominal voltage for comparison only. A 50A RV service has two 120V legs; total watts and total equivalent amps do not establish whether either individual 50A leg is overloaded. This calculator does not model leg balancing or individual branch circuits.
How to Use the RV Electrical Load Calculator
Before plugging in your RV at a campground, it helps to know how much electricity your appliances may need. This free RV electrical load calculator estimates the combined running watts, approximate startup peak and available power for a selected hookup. It is designed for RV owners planning appliance use on a road trip or at a campsite in the United States.
- Choose your RV power connection: 15-amp, 20-amp, 30-amp, 50-amp or inverter/generator.
- Keep 120 volts unless your equipment specifications call for a different nominal voltage.
- Choose a planning limit. The default 80% provides a conservative buffer for estimating load.
- Select only the appliances you expect to run at the same time.
- Enter each appliance's actual running and starting watts when available, then click Calculate Electrical Load.
RV Electrical Load Formula
Running watts = sum of (appliance running watts × quantity). For a basic 120V connection, estimated current in amps equals running watts divided by voltage. A 30-amp RV hookup at 120V has a nominal maximum of 3,600 watts. A 50-amp RV hookup commonly provides two separate 120V, 50-amp legs, for a nominal total of 12,000 watts.
Planning capacity = nominal supply watts × chosen planning percentage. With the default 80% planning limit, a 30A connection gives a target of 2,880 watts. This is a budgeting target, not a guarantee about what any specific breaker or circuit can safely carry.
30 Amp vs. 50 Amp RV Power
| RV connection | Nominal voltage | Nominal total power |
|---|---|---|
| 15 amp | 120 V | 1,800 W |
| 20 amp | 120 V | 2,400 W |
| 30 amp RV | 120 V | 3,600 W |
| 50 amp RV | 120/240 V split phase (two 120V legs) | 12,000 W total (6,000 W per leg at 120 V) |
Figures above assume nominal U.S. voltage. A 50-amp RV hookup must be evaluated by individual leg and circuit limits, not only total watts.
Why Startup Watts Matter
Some RV appliances, including air conditioners, refrigerators and water pumps, can briefly draw more power while starting. This calculator adds the largest estimated single-appliance startup increase to the running load, assuming motors start one at a time. Multiple motors starting together, power factor and inverter surge limits can produce different real-world results.
Frequently Asked Questions
How many watts can a 30 amp RV use?
At a nominal 120 volts, 30 amps corresponds to 3,600 watts. Actual safe usage also depends on the RV wiring, breaker, circuit arrangement and duration of the load.
How many watts does a 50 amp RV hookup provide?
A typical U.S. 50-amp RV hookup supplies two 120V legs at up to 50 amps each, or approximately 12,000 watts total. Each leg and branch circuit has its own limits.
Can I run an RV air conditioner and microwave together?
Possibly, depending on their actual wattage and the power connection. Enter both appliances to estimate their combined demand. Startup surge and individual circuit limits also matter.
What is the difference between running watts and starting watts?
Running watts describe normal operation. Starting watts are the brief extra power some motors need when switching on.
Does this calculator work for a 15 amp household outlet?
Yes. Choose the 15-amp option, but also verify that the outlet, extension cord and branch circuit are suitable and that other loads on the same circuit are considered.
Why is the default planning limit 80%?
It offers a conservative buffer for planning. It is not a universal statement that every RV appliance must always operate below 80% of a breaker rating.
Can I use this RV electrical calculator with a generator?
Yes. Select inverter/generator and enter its continuous AC output rating. Verify the generator's startup surge capability separately.
Does the calculator estimate battery runtime?
No. This tool estimates simultaneous AC electrical demand. Battery runtime depends on battery capacity, voltage, inverter losses and depth of discharge.
What if my appliance wattage is not listed?
Use the custom appliance row or edit an existing row's wattage. For better estimates, check the equipment nameplate or use a suitable watt meter.
Can total watts confirm that my 50 amp RV is safe?
No. A 50-amp RV service uses two 120V legs. A total under 12,000 watts can still overload one leg or a branch circuit if loads are not properly distributed.