Short answer: A fuel surcharge is a percentage added to the freight price that is adjusted in line with the diesel price, so the haulier does not carry the price risk alone. The formula is simple: fuel's share of your costs multiplied by the percentage price change from an agreed baseline. Example: if diesel makes up 25 per cent of your costs and the price has risen 12 per cent since the baseline in the contract, the surcharge is 25% × 12% = 3 per cent on the invoice. The key is that the baseline price, the source and the adjustment frequency are set out in black and white in the transport contract.
The diesel price is the most unpredictable major cost in transport. Wages, insurance and financing change annually and with notice; the pump price can jump ten per cent in a few days.
Without an agreed mechanism you have two bad options when the price rises: absorb the cost yourself, or have an uncomfortable renegotiation with every customer - mid-week, from a weak negotiating position. The fuel surcharge is the third way: a formula both parties have approved in advance, which adjusts in both directions. That last point matters more than many hauliers like to think - the surcharge must also come down when diesel gets cheaper. That is precisely what makes customers accept it.
The fuel surcharge is built on two numbers:
1. The fuel share: how large a part of your total costs is diesel. According to the cost index for road haulage from Statistics Norway (SSB), it typically lies between 10 and 27 per cent depending on segment - timber and long-haul at the top, distribution and waste collection lower. Use the figure for your own operation, not an industry average.
2. The price change: how much the diesel price has changed from the baseline set out in the contract.
The formula:
Fuel surcharge (%) = fuel share (%) × price change from baseline (%)
A haulier has agreed a baseline diesel price of NOK 16.00 per litre in the customer contract, and fuel makes up 25 per cent of costs. At the quarterly adjustment, the reference price is NOK 17.90 per litre.
Price change: (17.90 - 16.00) / 16.00 = 11.9%
Fuel surcharge: 25% × 11.9% = 3.0%
A shipment that would otherwise cost NOK 10,000 is then invoiced with NOK 300 in fuel surcharge, itemised on its own line. If the reference price falls to 15.20 the next quarter, the surcharge becomes negative - and is deducted. (The figures are examples only.)
A fuel surcharge is only as good as the contract wording behind it. Four things must be nailed down:
The baseline. Which diesel price (or index value) is the zero point, and from which date? This is the number everything is measured against.
The source. Use a neutral third party both sides can look up: SSB's cost index for road haulage has its own fuel component and is published quarterly - it is the most common reference in transport contracts in Norway. Alternatively, a list price from a named supplier. Never "our actual costs" - the customer cannot verify that.
The frequency. Monthly or quarterly adjustment is most common. Quarterly follows the SSB publication naturally; monthly gives a faster response but more administration. Choose one and write it down.
The visibility. The surcharge should appear as its own line on the invoice, in per cent and in currency. A visible surcharge comes across as tidy; a built-in mark-up comes across as a price increase.
The fuel surcharge only covers diesel. For longer contracts you should consider index-linking the whole freight price to SSB's total index for your vehicle group instead - it also captures wages, tolls and ferries, insurance and capital costs, and is published every quarter.
Rule of thumb: shorter contracts and spot-type work → fuel surcharge; multi-year contracts → full index-linking, possibly with a fuel surcharge as a more frequently adjusted component alongside. SSB publishes separate index variants excluding fuel, precisely so the two can be combined without counting diesel twice.
In practice the biggest problem with fuel surcharges is not the formula - it is the execution. The surcharge is agreed, the diesel price rises, and then: it is forgotten on every other invoice, calculated from the wrong baseline, or the customer is never notified of the adjustment.
This is where system support makes the difference. If the fuel surcharge lives as a rule in the TMS - per customer, with the right rate and automatic mark-up on the invoice basis - it is out of your head and into the structure. Then the quarterly adjustment is about updating one rate, not remembering a hundred invoice lines.
There is no single normal rate - the surcharge depends on your fuel share and how much the price has moved from the baseline in your particular contract. Two hauliers can have completely different surcharges in the same month and both be calculating correctly.
SSB's cost index for van and lorry transport is the standard in Norway. It is published quarterly, has separate figures per vehicle group and separate variants with and without fuel. Use the group that resembles your operation - or the equivalent index from the statistics agency or haulage association in your own country.
Yes. The mechanism is symmetrical, and the contract should say so. A haulier who only adjusts upwards loses trust - and often the customer - at the next tender round.
Not unilaterally, unless the contract allows for it. Use the next renegotiation or contract renewal - or have the conversation now and point out that a formula both parties can verify is tidier for both sides than ad hoc increases.
Same logic, different energy carrier: electricity or gas prices can fluctuate at least as much as diesel. Define the energy cost as a component and use a relevant price reference. If you run a mixed fleet, the surcharge can be differentiated per vehicle type - yet another argument for keeping it in a system rather than in your head.
This article was updated in August 2026. The worked examples are illustrations, not pricing recommendations.
In FleetX you set the fuel surcharge as a rule per customer - and it is included on every single invoice, automatically. See how.
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