RV calculators: choose the loading or power question

Choose the calculator for the decision you need: remaining cargo capacity, tow-vehicle loading, shore-power running loads, or battery and solar energy. Each uses your entries and stated assumptions. A result does not inspect equipment or replace actual weight and electrical checks.

Four distinct calculations

Start with the question
QuestionCalculator
What remains below GVWR after additions?Cargo capacity
How does this trailer loading use tow-vehicle allowance?Tow match
How does simultaneous running demand compare with supply?Shore power
What bank reserve and daily solar balance follow from my use?Power budget

Cargo capacity starts from a documented vehicle weight and subtracts only additions absent from it. Water, propane or batteries already aboard are not counted again. RV tow and payload calculation uses payload and vehicle ratings, with optional measured hitch weight and GCWR.

Shore power compares running watts and can divide 50-A loads between legs. It leaves starting demand, power factor and voltage acceptability for separate checks. Battery and solar energy budget converts energy at the entered bank voltage and makes the usable-capacity allowance explicit.

Choose an input you can documentRead the actual label, manual or measurementThen: Record what the measurement already includesThen: Replace defaults before making the purchase decisionChoose an input you can documentRead the actual label, manual or measurementRecord what the measurement already includesReplace defaults before making the purchase decision

A short weight example shows why input scope matters

Forty US gallons at this tool’s 8.34-lb/gal approximation add 333.6 lb when absent from the starting weight. They add zero further mass when the same water simply moves from fresh storage into waste tanks. An outside supply adding water is a different case.

Forty gallons divided between two tanksTwenty gallons remaining fresh: 166.8 lb; Same twenty gallons now waste: 166.8 lbForty gallons divided between two tanksTwenty gallons remaining fresh: 166.8 lbSame twenty gallons now waste: 166.8 lb

Calculation inputs can reach the fallback server

With the calculation script working, the arithmetic runs on the device. If scripts are unavailable, the form posts entries to this site’s server and returns a result. Do not enter names, addresses or other identifying information in numeric fields.

The result includes the calculator version and inputs. That record helps compare changed assumptions; it is not a stored account or guarantee that results remain available. Read privacy for the contact form and provider processing.

Follow actual vehicle, equipment and legal requirements together. A label, manual or regulation is not automatically dismissed by an invented priority order. Use weigh an RV on travel-ready scale passes and the actual supply arrangement to resolve the limits a calculator leaves open.