RV Leg Planner
Updated .
This planner checks one leg of a trip. From the leg distance, your average speed, the daily driving limit you choose and your rig’s fuel range, it returns the driving time, the fuel stops needed with a safety reserve you set, and whether you arrive before dark given your own departure and sunset times. Every limit is a personal choice, not a rule or a rating.
How it works
The planner works down this list, and shows each line in the result:
- Driving time = leg distance ÷ average speed.
- Days at your limit = driving time ÷ daily driving limit, rounded up.
- Usable range per fill = fuel range × (1 − reserve ÷ 100).
- Fuel stops = leg distance ÷ usable range, rounded up, minus 1. This assumes you start the leg with a full tank.
- Total time = driving time + (planned stops + fuel stops) × minutes per stop ÷ 60.
- Arrival = departure time + total time, compared with sunset. The latest departure that still meets your buffer is sunset − buffer − total time.
The limits are yours. The driving limit, the fuel reserve and the sunset buffer are personal choices. The driving limit is not a legal limit; rules written for commercial drivers, such as those from the Federal Motor Carrier Safety Administration, are separate and are not what this tool models. Take the fuel range from your own fill-ups, because a dash estimate changes with load, wind and grade.
The dark check. It runs only when the leg fits inside your daily limit, since a leg that needs two days has to be split into days first. Arriving after dark makes backing into and levelling on an unfamiliar site harder, so see the site fit and arrival checks guide and keep a backup campsite plan. Dusk visibility begins before sunset, so the buffer is worth entering.
Check the weather and grades separately. Wind, rain and long descents change both your speed and your fuel use; see the National Weather Service forecast for your route and the mountain grades and brakes guide. For the wider plan of fuel, water and dump stops, see plan legs, fuel, water and dump.
Worked example
Suppose a leg of 380 miles at an average of 55 mph, a daily limit of 8 hours, a hypothetical fuel range of 300 miles with a 25% reserve, 2 planned stops of 20 minutes each, a departure at 8:00 AM, a sunset time of 6:30 PM and a 30-minute buffer.
Driving time: 380 ÷ 55 = 6.91 hours, or 6 h 55 min; that fits in one day. Usable range: 300 × 0.75 = 225 miles, so 380 ÷ 225 rounds up to 2 fills, which means 1 fuel stop. Stops: (2 + 1) × 20 = 60 minutes. Total time: 6 h 55 min + 1 h = 7 h 55 min. Arrival: 8:00 AM + 7 h 55 min = 3:55 PM, which is 155 minutes before sunset and meets the buffer. The latest departure that still meets it is 10:05 AM.
Leave at 11:00 AM instead and the arrival is 6:55 PM, which is 25 minutes after sunset. Set the daily limit to 6 hours and the leg needs two days, so the dark check asks you to split it first. These numbers are illustrative arithmetic, not data about any route, rig or sunset.
Frequently asked questions
Where do I get my fuel range?
From your own fill-ups: the miles driven on a tank, taken from when you filled it to when you filled it again, with a margin you are comfortable with. Dash estimates change with load, wind and grade, so check them against what you actually used.
How is the reserve used?
The reserve is the share of the tank you never want to use between fuel stops. The tool reduces your range by that share and counts the fuel stops from the remaining distance per fill. It is your personal choice.
Why does it say to split the leg?
If the driving time is longer than the daily limit you entered, the leg cannot be done in one day, so a single arrival time would mislead. Choose an overnight stop and run each day as its own leg.
Where do I find the sunset time?
From a sunrise and sunset table for your arrival date and location. Enter the time for the place and day you will arrive, not where you start.
Does this send my numbers anywhere?
No. The calculation runs in your browser and nothing is stored or sent.
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