Fuel surcharges customers accept

Every haulier has had this conversation. The surcharge sits at 14 per cent, the customer’s new procurement lead has noticed it, and they would like to know what the 14 per cent is of and why it was 11 last year. You say diesel went up. They say diesel has since come down. Neither of you has anything to point at, the number gets talked down to 12, and the whole exchange repeats next quarter.

The trouble is not the size of the surcharge. It is that a bare percentage is not a mechanism — it is an opinion, and an opinion invites a counter-opinion. A surcharge that survives procurement has three properties instead: it is tied to a published index, its arithmetic can be reproduced by the customer without asking you, and it is symmetric. That last one is the one most carriers skip, and it is the one that buys the other two.

Why the flat percentage always ends up renegotiated

A percentage with no stated basis has three structural problems, and none of them are about trust.

It is unfalsifiable. Nobody can check it, which means nobody can be reassured by it. A customer who cannot verify a charge has only one lever available — argue the number down — so that is the lever they use.

It moves in one direction. Surcharges are raised in the month diesel spikes and lowered in the month a customer complains. Even when a carrier is scrupulous about this, the customer cannot tell the difference between a carrier who lowered it promptly and one who waited to be asked. The suspicion is free to hold and expensive to disprove.

And it has to be renegotiated to change, which is the worst part. If adjusting the surcharge means reopening a commercial conversation, then in a month when costs rise you either absorb the rise or spend goodwill. Indexing is not primarily about fairness. It is about removing a recurring negotiation from the calendar.

What indexing actually decides

“Index-linked” sounds like one decision. It is four, and vagueness in any of them puts the argument back where it started.

Which published series. Not “the diesel price” — a specific table from a specific publisher, named in the contract.

The base price. Your tariff already contains an assumed diesel price, whether or not anyone wrote it down. The surcharge is zero at that price and moves from there. If you cannot say what the base is, you cannot say what the surcharge compensates for.

The consumption assumption. Litres per 100 km, stated. This is what turns a price movement into money, and it is the number customers actually want to see, because it is the only one that is about your operation rather than about the market.

The cadence, and which figure governs which work. Monthly review using the previous month’s average is a common shape and an easy one to check. Weekly tracks costs more closely and produces more invoice lines to explain. Either is defensible; being unclear about which period’s figure applies to which period’s work is not.

The indices, by name

There is no need to invent a benchmark. Several are published, free, and already used for exactly this.

The EU Weekly Oil Bulletin is published by the European Commission and gives weekly consumer prices for petroleum products across EU countries, under Council Decision 1999/280/EC and Commission Decision 1999/566/EC. Member States submit on Wednesdays and the bulletin goes out on Thursdays. Usefully for contracts, it comes as two datasets — prices with taxes and prices without taxes — so you can name the one you mean.

Worth knowing before you pick: neither series is your cost. The with-tax series includes VAT, which a VAT-registered haulier reclaims. The without-tax series excludes excise duty, which you largely pay. So the published number will not equal what leaves your bank account either way. That is fine, and it is the point worth internalising about indices generally: an index has to move with your cost, not equal it. Pick one, name it, and let the base price absorb the difference in level.

In Sweden, SÅ Index does a broader job — it is the road haulage association’s shared tool for regulating cost development in transport contracts, covering fuel alongside personnel and other operating costs rather than fuel alone. Truck series are published around the 25th of each month, and in periods of sharp movement there is a separate model for weekly adjustment of fuel costs.

SÅ Index also illustrates why you name the series and not the organisation. Statistics Sweden calculated it until 31 December 2025; since then it has been produced on the association’s behalf by SBIX, Svenska Branschindex. A contract drafted as “as calculated by SCB” would have quietly broken on 1 January 2026. Name the index, name who publishes it today, and add a line saying what happens if it is discontinued or restated.

Outside Europe the equivalent is the US Energy Information Administration’s weekly On-Highway Diesel Fuel Price Survey, collected on form EIA-888 — the series most American surcharge tables are built on. The mechanism travels even where the market does not.

Symmetry is what makes it stick

An indexed surcharge that only ratchets upward is still an opinion; it has just acquired a footnote. The commitment that changes the conversation is the one where the surcharge goes down when diesel goes down, automatically, in the month it happens, without the customer having to notice and ask.

Be clear-eyed about what this costs. You give up the good months — the ones where prices fall and nobody mentions it for two quarters. That is a real loss, and it is the price of never again defending the number in the bad months. Most carriers find the trade worthwhile once they count the hours their sales staff spend on it.

If you want a deadband so that trivial movements do not generate paperwork — say, no adjustment inside a two per cent band — that is reasonable. Make it symmetric too, and write the figure down. A deadband that is generous in one direction only is the ratchet, rebuilt.

The other honest caveats

The index lags. Every published series describes a period that has ended. Weekly reduces the lag and multiplies the admin; monthly is the usual compromise. Neither eliminates it.

A national average is not your fuel card. Your bunkering, your mix of diesel and HVO, and where you actually fill up all mean the index and your invoice diverge. Over a year that mostly washes out. Over one bad month it will not, and pretending otherwise is how carriers end up quietly resenting the mechanism they proposed.

It only works if it is automatic. A surcharge that a person recalculates by hand each month gets skipped in a busy month, and a skipped month is not recovered — it is simply revenue you decided not to bill. If the recalculation is not somewhere it will happen without anyone remembering, the scheme degrades back into the percentage you started with.

Put it on the invoice

The final piece is nearly free and does most of the work: show the calculation. Index value, base value, the consumption figure, the resulting rate. A customer who can see the arithmetic stops auditing it, because there is nothing hidden to find. A customer who sees only “fuel surcharge, 14%” will keep asking, and they are right to.

Where navichain fits

navichain prices from services and price sheets — by weight, distance, time or geographic zone — so a fuel surcharge lives as a defined charge on the booking rather than a percentage somebody remembers to apply. When the index moves you change the figure in one place and everything priced afterwards carries it, and the charge appears as its own line from price sheet to posted invoice, with distance and fuel costed before you quote and tolls estimated across 20+ country regimes. If invoicing lag is the other half of your cash-flow problem, we wrote about that in invoice on delivery day; the pricing page and the platform page cover the rest, and every feature is on every plan from 995 kr a month.