Overlanding Multi-Terrain Fuel & Jerry Can Trip Planner

About This Tool

Most basic overlanding fuel calculators only do simple distance ÷ MPG — ignoring the fact that terrain dramatically changes consumption. This planner lets you break your trip into legs, assign a terrain mode to each, and applies the appropriate consumption multiplier. It then adds idle burn, a safety reserve, and a water carry estimate, giving you the full picture before you leave the tarmac.

How to Use the Planner

1. Set your vehicle's highway fuel efficiency (your real-world on-road figure, not the manufacturer's claim).
2. Enter your main tank size and how full it is at the start.
3. Enter your jerry can size (or 0 if not carrying any).
4. Set idle hours per day for camp running, and your engine's idle burn rate.
5. Fill in trip days, people, and daily water ration.
6. Add one row per trip leg — name it, enter the distance, choose a terrain mode. Adjust the consumption multiplier if you know your rig's actual off-road figure.
7. Read the result summary: total fuel needed (with reserve), jerry cans required, and water to carry.

Terrain Consumption Multipliers — Reference

These defaults come from real-world community data. Your rig may differ — use them as a starting point and adjust from your own experience.

Common Mistakes

• Using the manufacturer's MPG figure. Fully loaded with a roof tent, extra gear, and oversized tyres, your real-world figure is almost always worse. Measure it from a real tank fill-up.
• Ignoring idle time. Running the engine at camp for a fridge, charging, or warmth on a week-long trip can add 3–7 gallons (12–28 L) to total consumption.
• No safety reserve. Remote trails have no tow service. A 20% reserve is the community minimum; 30% in very remote areas.
• Treating the whole trip as one terrain type. A trip with a long highway transit and a short technical section needs per-leg calculation — averaging it loses accuracy.
• Under-planning water. In hot desert terrain, 2 L/person/day is insufficient. Plan 4–6 L plus a buffer.

Frequently Asked Questions

How much extra fuel does off-road driving use compared to highway?

Fuel consumption increases significantly off-road. On gravel/dirt roads expect roughly 15–25% more than highway. High-range 4WD on rough tracks adds 30–50%. Low-range driving, deep sand, or mud can double fuel use compared to highway. These are multipliers against your base highway consumption figure — the calculator applies them leg-by-leg.

How many jerry cans do I need for an overlanding trip?

That depends on total fuel needed minus your main tank capacity. The planner calculates net extra fuel after your main tank, then divides by your jerry can volume to give a count. Always carry at least a 20% safety reserve on top of calculated need. Common jerry can sizes are 5 gal (20 L), with 10 gal (40 L) options also available.

How much fuel does an idling 4WD use per hour?

A typical petrol 4WD or truck at idle burns roughly 0.5–1.0 gallon (2–4 litres) per hour depending on engine displacement. Diesel engines are more economical at idle. Running a fridge compressor or high-load accessories can push consumption higher. Enter your vehicle's actual figure in the idle consumption field.

How do I calculate water for an overlanding trip?

Minimum for drinking is 2–3 litres per person per day in temperate conditions. In desert heat, plan 4–6 litres/person/day. Add extra for cooking, washing, and a buffer. The planner multiplies your chosen daily ration by people and days to give a total target.

What safety fuel reserve should I carry overlanding?

Most experienced overlanders recommend a minimum 20% reserve on top of calculated fuel need. In very remote areas with uncertain refuel points, 25–30% is safer. The planner adds your chosen reserve percentage to the calculated total before working out jerry can count.