Fuel range when towing: how to plan a remote route without guessing

Fuel range when towing is a number you have to produce yourself, because nobody publishes it for you. The figure on the windscreen label and in the brochure comes from a laboratory test that does not include a trailer, and the Australian Government’s own Green Vehicle Guide lists “the load being carried or towed by the vehicle” among the things that make real consumption differ from it. Landscape South Australia puts the outback version more bluntly: “Your fuel economy will vary greatly on the tracks you take. Make sure you plan ahead and carry enough fuel between all stops.”

So the short answer runs in four steps. Measure your own consumption with the trailer on, loaded the way you travel, over a full tank. Divide the tank by that figure, then take a reserve off the top before you compare it with the gaps between fuel stops. Verify every fuel stop you are relying on, including which fuels it actually sells, using the official price-and-availability schemes where they exist. And if the arithmetic says you need extra fuel, carry it the way the state safety regulators describe, not in the cabin, and count its weight.

Geographic scope: the labelling rules are Commonwealth Australian Design Rules and apply nationally. The fuel-container guidance quoted is from WorkSafe Western Australia and WorkSafe Victoria; other states publish similar advice and their own dangerous-goods rules, so check yours. The land-manager advice comes from NSW, WA, SA and Queensland agencies. Product figures are the manufacturer’s own published specifications at the access date and are used as a worked example, not an endorsement.

Why the label figure is not your fuel range when towing

New light vehicles sold in Australia carry a fuel consumption label under Australian Design Rule 81/02. The Green Vehicle Guide explains what sits behind it: “The Standard requires testing of vehicles to a laboratory test procedure that is known as the New European Drive Cycle, or NEDC”, a procedure “Last updated in 1997” and “defined by the United Nations Economic Commission for Europe (UNECE) Regulation 101”. The test produces three values, “for ‘urban’ (low speed), ‘extra-urban’ (higher speed) and ‘combined’, which includes both”, and the guide notes that “the current fuel consumption label only displays the ‘combined’ value, when there can often be quite a range between the values”.

The government is candid about what the test leaves out. Its FAQ states: “These tests cannot and do not simulate all possible real-world driving conditions. This means the emissions and fuel consumption you may experience on the road will vary due to traffic and road conditions, the condition of your vehicle and how you use it.” Its real-world emissions page lists the variables the laboratory controls for and the road does not: “Traffic and weather conditions”, “The load being carried or towed by the vehicle”, “The use of accessories such as air conditioning and heating” and “How the driver speeds up and slows down”.

The label is changing, but not in a way that adds a trailer. ADR 81/03, registered on 20 November 2025, replaces the fuel consumption label with an energy consumption label based on the Worldwide harmonised Light vehicle Test Procedure, or another procedure the rule recognises. The Green Vehicle Guide describes the WLTP as introduced “to replace the NEDC procedure through UN Regulation 154”. The new rule applies from “1 July 2026 for new models” and “1 July 2028 for all models”. A WLTP figure is still a laboratory figure for an unladen vehicle; it is a better comparison tool between vehicles, not a towing prediction.

Manufacturers say the same thing in their own fine print. Isuzu UTE Australia’s current D-MAX specification sheet, which lists a 76-litre fuel tank and ADR 81/02 combined figures between 6.3 and 7.8 L/100 km depending on the variant, carries the note that the figures “are to be used for vehicle comparison purposes only. Actual fuel consumption & emissions will vary depending on many factors including, but not limited to, traffic conditions, individual driving style & vehicle condition.” The tank capacity is a fact you can plan with. The consumption figure is not, once the trailer is on.

Figure	Where it comes from	What it is good for	What it cannot tell you
Label combined L/100 km	ADR 81/02 laboratory test (NEDC) until the ADR 81/03 WLTP label phases in from 1 July 2026	Comparing one vehicle with another	Consumption with a trailer, a loaded vehicle, a headwind or a corrugated track
Fuel tank capacity	Manufacturer specification	The only fixed input in the range calculation	How much is usable before the pump starves on a slope, which the handbook may or may not state
Dashboard range readout	The vehicle’s own recent consumption history	A rough live check once it has learned towing consumption	Range on the next leg if the last tank was solo highway driving
Your brim-to-brim figure	Your vehicle, your trailer, your load, your roads	Planning the trip you are actually taking	Consumption on a surface or in weather you have not yet measured

Measure your own towing consumption

The measurement is simple and the only hard part is discipline. Fill the tank to the first click at a pump, note the odometer, tow the way you will tow on the trip, then refill to the first click at the same kind of pump and note the litres and the distance. Litres divided by kilometres, multiplied by 100, is your towing figure for that kind of driving. Do it over a full tank rather than a short hop, because a few litres of error on a 20-litre fill is a large error on the result.

Three things make the figure worth having.

• Load it the way you travel. Water, food, recovery gear, a full fridge and the people who are coming. The trailer with its tanks full if that is how you will leave the last town. Our remote camping water planning guide uses the same logic for water: measure your own use, then plan from it.
• Measure the surfaces separately if you can. Landscape SA’s outback safety advice is explicit that “Heavy track conditions such as soft sand, muddy tracks and slow, hilly terrain will increase your fuel consumption.” A highway figure will not carry a sand track. If the route has a long unsealed section, a separate measurement on gravel with the trailer on is the best predictor you will get; if you cannot get one, treat the unsealed leg as a larger unknown and give it a larger reserve. Our guide to reading unsealed-road warnings with a camper trailer covers what the official notices say about surface and recent rain.
• Do not trust the range readout until it has caught up. The distance-to-empty figure on the dash is derived from recent consumption. A week of solo commuting before departure teaches it a number that stops applying the moment the trailer is hitched. Reset the trip computer when you hitch up, and treat the readout as a live sanity check against your own arithmetic, not as the plan.

The fuel range worksheet

Work in litres and kilometres and keep the reserve visible as its own line, so that “we can make it” never quietly means “we can make it with nothing left”.

Line	Item	Example	Where the number comes from
A	Tank capacity	76 L	Manufacturer specification (Isuzu D-MAX example)
B	Label combined figure	7.8 L/100 km	Windscreen label or specification sheet; shown for contrast only
C	Theoretical label range (A ÷ B × 100)	974 km	Arithmetic; not a planning figure
D	Your measured towing figure	say 13.0 L/100 km	Your brim-to-brim test with the trailer on; the example value is a placeholder, not a D-MAX figure
E	Full-tank towing range (A ÷ D × 100)	585 km	Arithmetic
F	Reserve you will not plan to use	say 25 per cent, 146 km	Your decision; see below
G	Planning range (E − F)	439 km	The longest gap between guaranteed fuel you will accept on a full tank
H	Longest gap on the route between verified fuel	measured on the map	Your route, after checking each stop
I	Extra fuel needed if H exceeds G	(H − G) × D ÷ 100	Arithmetic, then rounded up to whole containers

Two things to notice in the example. The label range (line C) is more than twice the planning range (line G), and the whole difference is the trailer, the load and the reserve, none of which the label knows about. And the extra-fuel line only appears once the reserve is already in the sum; extra fuel is for closing a gap, not for replacing the margin.

Choosing the reserve

No Australian authority publishes a percentage, and this guide does not invent one. The land managers instead describe what the reserve is for. Main Roads Western Australia’s remote-travel checklist wants “Enough food and water to last for 2 to 3 days past your intended travel time”, and lists “Extra fuel if travelling long distances”. Explore Parks WA tells travellers to “Carry extra fuel and water with you in case you get lost or your vehicle breaks down.” The South Australian Desert Parks Bulletin asks visitors to “Take extra water, food and fuel supplies” and to “Check road and weather bulletins and local conditions before travelling into the Outback.”

Read together, the reserve has to cover things that add distance or consumption after you have left the last pump: a closed road and the detour around it, a soft section driven in low range, a headwind, a wrong turn, a run back to a homestead or a ranger station for help, and an outlet that is shut or dry when you arrive. Size it to the leg with the most of those, not to the average. A route with a bitumen highway between two towns needs a smaller reserve than a route with an unsealed crossing where the surface changes with the weather. Our guide to checking national park road closures before towing explains how a closure turns into a detour that eats fuel.

Verify each fuel stop, and what it sells

Every outback safety page says the same thing in different words. NSW National Parks: “Check the locations of local food and fuel supplies before you go”, and, in its outback survival tips, “Plan every detail of your trip, like where the petrol stations are”. Queensland’s StreetSmarts: “refuelling – it can be a long way between petrol stations in the outback”. None of them says that a dot on a map is a fuel stop. A remote outlet has hours, a fuel list and a supply chain, and each of those can fail on the day.

Three checks turn a map symbol into a fuel stop you can plan around.

Check that it exists and is open

Phone ahead, or use the official schemes where a state runs one. The point of these schemes for a towing crew is not the price; it is that they list outlets, fuel types and, in NSW, availability.

Jurisdiction	Official scheme	What the source says it does
NSW	FuelCheck (NSW Government)	Operators must register “details about the types of fuel available” and “notify if a type of fuel becomes unavailable”; motorists can “search for fuel by type or brand” and “search fuel availability”
WA	FuelWatch (Consumer Protection WA)	“The FuelWatch scheme includes every fuel retailer in Western Australia”; retailers “must notify FuelWatch of their next day’s prices by 2pm each day”, and those prices are “‘locked in’ for 24 hours from 6am the following day”
Queensland	Fuel price reporting scheme (Queensland Treasury)	“Access fast and free updates on real-time fuel prices on your phone using apps and websites that have signed up to receive data under Queensland’s fuel price reporting scheme”

Other jurisdictions run their own price-reporting arrangements; check the relevant government site rather than a third-party app for the authoritative list. A scheme listing tells you an outlet is registered and what it reported; it does not tell you the pump is working this afternoon, so for the stops your range depends on, a phone call the day before is still the check that counts.

Check which fuel it sells

The second check is the one that catches diesel-only or low-aromatic-only outlets. Across northern and central Australia, the Commonwealth’s low aromatic fuel programme stocks low aromatic fuel in place of, or alongside, regular unleaded. The National Indigenous Australians Agency states that “There are around 190 retail sites across Queensland, the Northern Territory, Western Australia and South Australia that stock low aromatic fuel”, that it “has a minimum octane rating of 91 and can be used in any engine in which manufacturers recommend the use of regular unleaded petrol (91)”, and that “From 2022, low aromatic fuel has been dyed purple to make it easily identifiable.” The agency’s fact sheet adds that it “meets all the specifications for regular unleaded 91 fuel” and that these fuels “can be mixed in your petrol tank”.

For a petrol tow vehicle whose handbook accepts 91, this changes nothing but the colour. For a vehicle whose manufacturer requires 95 or 98, the question is whether the outlet sells it, and the answer is outlet by outlet; the NIAA notes some sites that sell premium alongside low aromatic fuel, and does not claim that all do. A diesel tow vehicle has the opposite problem: some small outlets are petrol-only. Neither case can be settled from the label on the map. Ask.

Check that you can pay and that the leg is still open

Remote outlets keep their own hours, and a card terminal needs power and a connection, so carry a way to pay that does not depend on a single card or a working terminal, and refuel when you pass fuel rather than when the gauge asks. The road matters as much as the pump: if the leg between two stops closes after rain, the detour may add a full stop’s worth of distance. Check the land manager’s alerts and the state road report before each remote leg, as our guides on road closures and flood-season checks describe.

Carrying extra fuel legally and safely

When line I on the worksheet is more than zero, the safety regulators have already written the rules for how the fuel travels. NSW National Parks phrases the recommendation carefully: “consider carrying extra fuel in a suitable fuel container”. The word “suitable” has a specific meaning.

The container

WorkSafe Western Australia states that “Petrol should be transported in United Nations approved jerry cans that comply with Australian Standard AS 2906”, and that “The capacity of containers filled with petrol at service stations is limited to 25 litres.” WorkSafe Victoria describes the same limit and tells buyers to “Look for UN package approval markings which indicate that the container has been manufactured to meet the mandatory requirements of the Australian Code for the Transport of Dangerous Goods Code by road and rail (ADG Code)”. A container that does not seal, or has no markings, is not a fuel container for this purpose.

Filling

WorkSafe Victoria’s filling rules are short and worth quoting in full order. “Always place portable fuel containers on the ground away from all possible ignition sources when open for filling.” “Keep one hand on the container while filling to reduce the likelihood of static electricity build up and discharge.” “Use an earthing strap if there is one supplied by the service station”. “Ensure the container cap is replaced tightly on the filled container before attempting to lift and place the container back in the vehicle.” And the rule that matters most to a camper trailer crew: “Flammable liquids should never be decanted inside vehicles or on trailers, boats, caravans or motorcycles.”

Where it rides

WorkSafe WA describes the hazard: “If petrol fumes vent from a container inside a vehicle, it can form an explosive fuel and air mixture.” Its remedy is placement and restraint: “Transport small containers of petrol (properly restrained) in a trailer or ute tray”, “securely restrain containers in an upright position on the vehicle”, and if a container has to travel in the cabin, “wind down the vehicle windows for cross-flow ventilation” and “do not smoke or vape in or near the vehicle”. WorkSafe Victoria adds that containers should be carried “in a secured and upright position, away from heat sources, such as the sun, in a well ventilated space.” For a camper trailer, that points to a rack on the drawbar or a purpose-built holder on the trailer, never the footwell, and never loose on the trailer floor.

The weight

Extra fuel is payload, and it lands on a drawbar or a rear rack that already carries the tow-ball load. The Commonwealth diesel standard sets density at 15 °C between 820 and 850 kg/m³, so a 20-litre container of diesel holds roughly 16.4 to 17 kg of fuel before the container’s own mass. BP’s Australian safety data sheet for Unleaded 91 gives a density of “710 to 750 kg/m³”, so 20 litres of petrol is roughly 14.2 to 15 kg. Two full 20-litre containers on a drawbar are 30 kg or more added to the coupling side of the trailer, which changes ball weight and the trailer’s loaded mass. Weigh the combination, or at least redo the sums, with the containers full.

Rule or advice	What it says	Who says it
Container standard	“jerry cans that comply with Australian Standard AS 2906”, UN package approval markings	WorkSafe WA, WorkSafe Victoria
Maximum fill	Containers filled at service stations are “limited to 25 litres”	WorkSafe WA, WorkSafe Victoria
Filling	On the ground, one hand on the container, earthing strap if provided, cap on before lifting	WorkSafe Victoria
Never decant	“never be decanted inside vehicles or on trailers, boats, caravans or motorcycles”	WorkSafe Victoria
Placement	“in a trailer or ute tray”, “upright”, restrained, ventilated, away from heat	WorkSafe WA, WorkSafe Victoria
Weight	20 L of diesel is about 16.4–17 kg of fuel; 20 L of Unleaded 91 about 14.2–15 kg, plus the container	Commonwealth diesel standard; BP safety data sheet

If the plan fails anyway

The reason every land manager pairs the fuel advice with a communications line is that fuel planning fails quietly, usually well past the last pump. NSW National Parks asks remote travellers to “consider filling in a trip intention form and taking a personal locator beacon” and to “Give your route details to family and friends who are not travelling with you.” Queensland’s advice is to “give friends, neighbours or the police the details of your route”. A tow vehicle with an empty tank on a remote track is a vehicle breakdown, and the right response is the one in our remote area communications guide: stay with the vehicle, use the beacon or messenger you registered before you left, and let the plan you lodged do its work.

Before you leave

1. Brim-to-brim test done with the trailer on and the vehicle loaded, on the surface the trip will use, with the result written down as L/100 km.
2. Worksheet completed: tank capacity from the manufacturer, your measured figure, a reserve as its own line, and the planning range that results.
3. Every fuel stop the route depends on confirmed by phone or through the state scheme, including fuel types, hours and a way to pay if the terminal is down.
4. Low aromatic fuel checked against the handbook if the tow vehicle needs more than 91 octane.
5. Extra fuel, if the worksheet demands it, in AS 2906-compliant containers of 25 litres or less, filled on the ground, carried upright and restrained outside the cabin, with its weight added to the trailer sums.
6. Road and weather reports checked for each remote leg, because a detour is the fastest way to turn a comfortable range into a marginal one.
7. Route and timings left with someone who is not travelling, and a beacon or satellite messenger registered and aboard.

Rules and outlets change. The container rules quoted here are the current WorkSafe guidance at the access date; the outlets, fuel types and hours on any route are only as current as your last phone call.