Fuel 
Before any big drive, the same question comes up: what's this going to cost me in fuel? The good news is you don't need an app or a spreadsheet to get a solid estimate - just three numbers and one bit of primary-school maths. Get those three numbers right and you'll be within a few dollars of the real figure, which is close enough to budget a road trip or split costs with mates.
This guide gives you the formula, then runs the actual numbers on a Brisbane to Sydney trip (about 920 km) and a few shorter local runs. Every dollar figure here states its assumptions, so you can swap in your own car and today's price. If you'd rather skip the maths entirely, the Fuel Daddy fuel cost calculator does it for you - free, no sign-up.
The road trip fuel cost formula
Here's the whole thing. Your fuel cost for any trip is:
Distance (km) ÷ 100 × fuel use (L/100km) × price ($/L) = total cost
You need three numbers:
- Distance - the one-way kilometres (double it for a return trip). Grab this from any maps app.
- Fuel use - your car's litres per 100 km. Check the trip computer, or use a rough guide: small petrol car around 6–7, mid-size SUV around 8–9, large 4WD or ute around 10–12.
- Price - the price per litre, in dollars. So 185 c/L is $1.85.
That's it. One quick worked example: a 500 km drive in a car using 8 L/100km at $1.85/L costs 500 ÷ 100 × 8 × 1.85 = $74. Highway driving usually returns a litre or two better than the city figure, so if anything this formula slightly overestimates - which is the safe way to round when you're budgeting.
What does Brisbane to Sydney cost in fuel?
The drive from Brisbane to Sydney is roughly 920 km one way via the Pacific Highway and M1. Plug that into the formula with a mid-size car and a typical 2026 highway price:
At 8 L/100km and 185 c/L: 920 ÷ 100 × 8 × 1.85 = about $136 one way, or around $272 return.
That figure moves a lot with your car and the pump price, so here's the same 920 km drive at different consumption rates, all at the same 185 c/L, so you can find the row closest to your vehicle:
| Vehicle type | Fuel use | One way (920 km) | Return |
|---|---|---|---|
| Small petrol car | 6.5 L/100km | ~$111 | ~$222 |
| Mid-size car / small SUV | 8 L/100km | ~$136 | ~$272 |
| Large SUV / 4WD | 10 L/100km | ~$170 | ~$340 |
| Ute or 4WD towing | 13 L/100km | ~$221 | ~$442 |
All figures above assume a flat 185 c/L and the stated consumption. Running on diesel? The litres-per-100 are usually lower, but diesel often prices higher, so the totals tend to land in a similar ballpark - our diesel vs petrol guide breaks down which actually works out cheaper for your driving.
What about shorter runs - Gold Coast, Sunshine Coast, Newcastle?
The same formula handles the everyday trips just as well. Here are a few popular runs, all worked at 8 L/100km and 185 c/L so they're directly comparable - swap in your own numbers as needed:
| Trip | Approx. one-way distance | Fuel cost one way | Return |
|---|---|---|---|
| Brisbane → Gold Coast | ~80 km | ~$12 | ~$24 |
| Brisbane → Sunshine Coast | ~100 km | ~$15 | ~$30 |
| Sydney → Newcastle | ~160 km | ~$24 | ~$48 |
| Gold Coast → Byron Bay | ~95 km | ~$14 | ~$28 |
The lesson from those numbers is that the weekend run to the coast is genuinely cheap - a Gold Coast day trip is roughly the price of two coffees in fuel. It's the long interstate haul where the price per litre really starts to bite, which is exactly where filling up smart pays off.
Where do you fill up cheapest on a road trip?
The single biggest mistake on a long drive is filling up at a highway service centre out of convenience. Those big roadhouse stops are often 15 to 30 cents a litre dearer than a regular servo in a nearby town, because they can charge a premium to a captive audience. On a 60-litre fill, that gap is $9 to $18 you've handed over for nothing.
The fix is simple: fill up before you leave the city while prices are competitive, then top up in regional towns rather than at the big highway plazas. A few minutes off the highway into a town like Grafton, Coffs Harbour or Taree usually beats the servo right on the motorway. Check live prices along your route on the Fuel Daddy live map - it shows every station's current price, so you can see which town stop is worth the small detour. Timing matters too in the cities you start and finish in; our best time to buy fuel guide explains the price cycle.
Why towing and a loaded car costs so much more
If you're towing a van, boat or camper - or just packed heavy for a family holiday - expect your fuel use to climb 30 to 60 per cent above the normal figure. A car that sips 8 L/100km solo can easily drink 12–13 L/100km hauling a caravan into a headwind. That's not a rounding error; it can turn a $136 Brisbane–Sydney run into $200-plus.
The extra comes from three things: weight, wind resistance and the drag of the trailer behind you. A boxy caravan punches a much bigger hole in the air than your car does on its own, and that gets dramatically worse at higher speeds. If you're towing, use the upper end of the consumption ranges in the tables above - the 13 L/100km row is a realistic starting point for most caravan setups, and heavier rigs go higher still.
How do you cut road trip fuel costs?
You can't change the distance, but a few easy habits genuinely move the needle on a long drive. None of these are dramatic on their own - stacked together they can shave a real chunk off the total.
- Check your tyre pressures. Under-inflated tyres can add several per cent to fuel use. Set them to the placard pressure (often a touch higher for a loaded car) before you leave.
- Ease off the speed. Fuel use rises sharply above about 100 km/h. Sitting on 100 instead of 110 on a long highway stretch noticeably cuts consumption with barely any difference to arrival time.
- Drop the dead weight. Clear out the boot of stuff you're not using, and pull off the empty roof rack or pod - an unused roof box is pure drag.
- Drive smoothly. Steady throttle and gentle braking beat constant acceleration. Cruise control on open highway is your friend.
- Fill smart, not desperate. Plan your stops around cheaper towns rather than topping up in a panic at the dearest roadhouse on the route.
The bottom line
Working out a road trip's fuel cost takes one formula and three numbers: distance ÷ 100 × L/100km × price per litre. A Brisbane to Sydney run lands around $136 one way in a typical mid-size car at 8 L/100km and 185 c/L - more if you're in a big 4WD or towing, less in a small hatchback. Local runs to the Gold Coast or Sunshine Coast are pocket change by comparison.
Whatever you drive, the two levers that matter most are where you fill up and how heavy your right foot is. Fill before the highway, skip the pricey roadhouses, and check live prices along the way on the fuel map. To run the exact numbers for your own car and trip, use the Fuel Daddy fuel cost calculator.
