What is a diesel floater?

A clause that moves the freight price with the diesel price. The contract fixes a reference diesel price and the share of fuel in the freight price. When diesel costs more than the reference, a surcharge applies. When it costs less, the price falls. Both sides avoid a new negotiation every time diesel moves.

How do I calculate a fuel surcharge?

Take the diesel price now, minus the reference price, divided by the reference price. Multiply the result by the fuel share. With a reference of 1.50 EUR, a price of 1.62 EUR and a fuel share of 30%, the surcharge is 8% × 30% = 2.4% of the freight price.

Which fuel share should I enter?

The share written in your contract. The fuel share differs by route, truck and contract, so this calculator gives no default for your case. The example uses 30% only to show the method. If your contract uses a table of steps, use the table, not the formula.

Can the fuel surcharge be negative?

Yes. When diesel costs less than the reference price, the same formula gives a negative number. The freight price then falls by that percentage. Some contracts set a threshold, so small changes in either direction change nothing.

Should I use diesel prices with or without VAT?

Use the basis your contract names, and use it for both prices. A reference without VAT compared with a price with VAT gives a wrong surcharge, because the VAT part moves too.

Fuel surcharge calculator for road freight (diesel clause)

RNJ Transport’s free fuel surcharge calculator applies the share method of a diesel clause. Enter the reference diesel price from your contract, today’s price and the fuel share of the freight price. The surcharge is the diesel price change times the fuel share. A negative result lowers the price.

We filled in an example. Change any number to see your own result.

Your result

+2.4% Fuel surcharge

Diesel price change: +8%
Surcharge amount: +36.00 EUR
New freight price: 1,536.00 EUR

Diesel is 8% above the reference. The freight price rises by 2.4%.
Use the same basis for both diesel prices: both with VAT or both without.

The button adds these numbers to the price form at the bottom of this page.

A diesel clause, also called a diesel floater, moves the freight price with the diesel price. The contract sets the reference price and the fuel share.
Surcharge = (diesel price now − reference price) ÷ reference price × fuel share.
Example: diesel 8% above the reference with a 30% fuel share gives a 2.4% surcharge.
The same clause lowers the freight price when diesel falls below the reference.

How the share method works

The share method splits the freight price into a fuel part and the rest. Only the fuel part moves with the diesel price. The calculator takes the change of the diesel price against the reference price and multiplies it by the fuel share. The result is the surcharge on the whole freight price.

In the example, the contract reference is 1.50 EUR per litre and diesel now costs 1.62 EUR. That is 8% more. With a fuel share of 30%, the surcharge is 8% × 30% = 2.4%. On a freight price of 1,500 EUR, the surcharge is 36 EUR, and the new price is 1,536 EUR.

What your contract decides

The calculator follows the numbers in your contract. Some contracts use a table of steps instead of a formula. If yours does, use the table. Check these points in your diesel clause before you calculate.

The reference price and the date it was set
The source of the diesel price, for example a national index or a weekly bulletin
The fuel share of the freight price
How often the surcharge changes, for example every month or every quarter
Any threshold below which nothing changes
Prices with VAT or without VAT

Diesel prices to compare

The European Commission publishes average fuel prices for every EU country each week in its Weekly Oil Bulletin, with and without taxes. Use the source your contract names, and use the same source for the reference price and for the price now.

RNJ Transport gives you one fixed price for a load before booking. Ask us how fuel is handled in a price for regular loads on your route.

Sources (2)

Numbers checked on 19 October 2026

Frequently asked questions

What is a diesel floater?

A clause that moves the freight price with the diesel price. The contract fixes a reference diesel price and the share of fuel in the freight price. When diesel costs more than the reference, a surcharge applies. When it costs less, the price falls. Both sides avoid a new negotiation every time diesel moves.
How do I calculate a fuel surcharge?

Take the diesel price now, minus the reference price, divided by the reference price. Multiply the result by the fuel share. With a reference of 1.50 EUR, a price of 1.62 EUR and a fuel share of 30%, the surcharge is 8% × 30% = 2.4% of the freight price.
Which fuel share should I enter?

The share written in your contract. The fuel share differs by route, truck and contract, so this calculator gives no default for your case. The example uses 30% only to show the method. If your contract uses a table of steps, use the table, not the formula.
Can the fuel surcharge be negative?

Yes. When diesel costs less than the reference price, the same formula gives a negative number. The freight price then falls by that percentage. Some contracts set a threshold, so small changes in either direction change nothing.
Should I use diesel prices with or without VAT?

Use the basis your contract names, and use it for both prices. A reference without VAT compared with a price with VAT gives a wrong surcharge, because the VAT part moves too.

Other free tools

Price for your regular loads

Send the route, the dates and the load size in the price form. You can also call us. We give you one fixed price for each load before booking.

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