Truck Fuel Consumption per 100km: Benchmarks, Calculation and How to Reduce It

Truck fuel consumption per 100km: a flatbed truck on a desert highway

How many liters of diesel does a truck use? It is one of the most common questions from fleet managers and transport companies, because diesel is often the largest operating cost after salaries. Truck fuel consumption depends on the type of truck, the load, the road and the driving style, but reference figures help you judge whether your fleet’s numbers are normal. This guide covers truck fuel consumption per 100km, how to calculate it for your own trucks, why it rises and how to bring it down.

The full picture: read our fleet fuel management guide.

Truck Fuel Consumption per 100km: Reference Figures

In tests by the International Council on Clean Transportation (ICCT) on European trucks, a typical 40-tonne tractor-trailer used about 32.6 liters per 100 km on the long-haul cycle, and the best truck in its class used 29.9 liters. In other words, a loaded tractor-trailer covers roughly 3 km per liter of diesel under test conditions.

  • Lighter trucks such as pickups and distribution trucks use less per kilometer, but frequent stops and starts in the city raise their consumption relative to their size.
  • Conditions in Saudi Arabia differ from test conditions: high heat, air conditioning, sandy or mountain roads and heavy loads all push the numbers up.

So treat published figures as a starting point only. The most accurate benchmark for truck fuel consumption is your own fleet’s data for each truck type and each route.

How to Calculate Your Truck’s Fuel Consumption

The formula is simple: consumption (liters per 100 km) = (liters used ÷ kilometers driven) × 100.

  1. Fill the tank completely and record the odometer reading.
  2. At the next full fill-up, record the liters added and the new odometer reading.
  3. Divide the liters by the kilometers driven and multiply by 100.
  4. Repeat over several fill-ups and take the average, because a single reading can mislead.

Example: a truck drove 10,000 km in a month and used 3,400 liters. Its rate is (3,400 ÷ 10,000) × 100 = 34 liters per 100 km, or about 2.9 km per liter. For heavy equipment, liters per engine hour is a better measure than kilometers.

Calculating truck fuel consumption by hand is fine to start with, but it becomes tiring for large fleets. Fleet fuel monitoring systems calculate the rate automatically for every vehicle, using CAN Bus data or a sensor in the tank.

How to Estimate Your Monthly Diesel Cost

The monthly cost of truck fuel consumption differs from truck to truck depending on distance, load and route, but the way to calculate it stays the same:

  • Cost per truck = liters used in the month × the price per liter published by Saudi Aramco at the time.
  • Fleet cost = the sum for all trucks, ideally calculated truck by truck, because consumption varies between them.
  • Any small cut in consumption is multiplied by the number of trucks and the months of the year, so every point of saving is worth tracking.

Fuel prices are reviewed periodically, so update the price in your calculations whenever it changes.

Why Does Truck Fuel Consumption Rise?

  • Load: the heavier the load, the higher the truck fuel consumption, so compare trucks with similar loads or calculate consumption per tonne carried.
  • Speed: air resistance grows quickly with speed, so consumption climbs clearly on highways. Speed limits with overspeed alerts are one of the fastest ways to save.
  • Idling: the U.S. Department of Energy estimates that a heavy truck burns about 3.4 liters per hour while parked with the engine running. Two hours a day of idling for air conditioning in summer, over 26 working days, means about 177 liters a month per truck burned without moving.
  • Tire pressure: according to the U.S. EPA SmartWay program, tires 10 psi below the recommended pressure can cut fuel efficiency by about 0.5% to 1%, and under-inflation is also a safety risk in high heat.
  • Maintenance: clogged air filters, injectors, wheel alignment and sticking brakes. A sudden rise in one truck but not in similar trucks usually points to a technical problem. A fleet management system helps you schedule maintenance on time.
  • Route and road: mountain and sand roads, congestion and extra distance. See route optimization.
  • Driving style: harsh acceleration and sudden braking. See driver behavior monitoring.
  • Unexplained losses: fuel siphoned from the tank or inflated fuel receipts.

When Is a Truck’s Consumption Abnormal?

  • When its rate rises clearly above its own average for the previous three months, for example by 10% or more, with no change in load or route.
  • When it uses more than similar trucks with similar loads on similar routes.
  • When the tank level drops while the truck is parked with the engine off.
  • When the quantity on the fuel receipt is larger than the actual rise in the tank.

7 Steps to Reduce Truck Fuel Consumption

  1. Set a baseline for each truck and each truck type, and review it monthly.
  2. Set a speed limit with alerts when it is exceeded.
  3. Introduce a clear idling policy and review idling hours weekly for each driver.
  4. Check tire pressure regularly, especially in summer.
  5. Link preventive maintenance to actual kilometers and engine hours.
  6. Plan routes to cut extra kilometers and empty trips.
  7. Share consumption figures with drivers and reward the best performers.

Truck fuel consumption also depends on the vehicles themselves: when you renew the fleet, remember that fuel-efficiency technologies in modern trucks, such as improved aerodynamics, tires and engines, could cut long-haul fuel use by up to 27% according to ICCT estimates for European trucks.

Frequently Asked Questions

How many liters per 100 km does a tractor-trailer use?

In ICCT tests, a typical 40-tonne European tractor-trailer used about 32.6 liters per 100 km. Real consumption varies with load, road, speed and heat.

How do I calculate a truck’s diesel consumption?

Divide the liters used by the kilometers driven and multiply by 100. For example, 3,400 liters over 10,000 km means 34 liters per 100 km.

How much fuel does an idling truck use?

The U.S. Department of Energy estimates that a heavy truck idles at about 3.4 liters per hour, and more with air conditioning and accessories running.

Do heat and air conditioning affect diesel consumption?

Yes. Air conditioning adds load to the engine, and the biggest effect usually comes from leaving the engine running at stops to cool the cab in summer.

How do I know if one truck’s consumption is abnormal?

Compare it with its own average for previous months and with similar trucks on similar routes. A clear rise with no change in load or route deserves a check of maintenance, driving style and fuel records.

How Afaq Alrasd Aldhki Can Help

We help you see your real truck fuel consumption by reading fuel use for each truck through CAN Bus or a tank sensor, and by tracking liters per 100 km, idling hours and speeding on Afaq Platform, with installation and technical support. Explore fleet fuel monitoring, or request a quote to start measuring your fleet’s consumption.

References