Powerful Fuel Surcharge Calculator for UK Haulage
Calculate a transparent diesel fuel surcharge using actual vehicle MPG and mileage, or an agreed contract percentage method. Review loaded and empty miles, cost per mile, VAT and the revised transport invoice in seconds.
Quick guide: calculate a fair fuel adjustment
- Choose the method.
Use actual fuel cost for a vehicle-based calculation or contract percentage for an agreed index formula. - Enter fuel prices.
Add the contract base diesel price and current diesel price on the same VAT basis. - Add job details.
Enter loaded and empty miles, MPG or L/100km, and the original transport charge. - Review and export.
Check the full calculation, then save it or download a PDF/CSV record.
Journey and contract details
Recent calculations saved on this device
How the UK Fuel Surcharge Calculator Works
A fuel surcharge is a separate, transparent adjustment that helps a carrier or owner-driver recover an agreed change in diesel cost. It should follow the written transport contract, use a consistent fuel-price source and state the base price, current price, effective date and mileage basis.
Actual Fuel-Cost Method
This method estimates litres used from the vehicle’s UK imperial MPG or L/100km and multiplies that fuel quantity by the change in pence per litre. It is useful where the parties want the adjustment linked to the specific journey.
Contract Percentage Method
This method multiplies the percentage change in diesel price by the agreed fuel share of the original haulage charge. Use the fuel-cost share stated in your customer or subcontractor agreement.
Loaded and Empty Mileage
Chargeable mileage can include loaded travel, empty running, depot positioning or return mileage only where the commercial agreement allows it. The calculator keeps loaded and empty miles visible for a clearer audit trail.
VAT and Invoice Totals
Enter the original transport charge excluding VAT and the applicable VAT rate. The result shows the fuel adjustment, revised charge excluding VAT, VAT amount and revised invoice total. Confirm the correct VAT treatment with your accountant.
Contract adjustment % = diesel price change % × agreed fuel-cost share %
Revised charge ex VAT = original charge + fuel adjustment
Fuel-price source: use the price source specified by your contract. For an independent reference, the UK government publishes average retail petrol and diesel prices in its weekly road fuel prices.
Important: this is a commercial planning and quotation tool, not accounting, tax or legal advice. It does not create a contractual right to impose a surcharge. Confirm the formula, index, VAT basis, rounding and effective date in the relevant customer agreement.
Fuel Surcharge Calculator FAQs
What is the difference between a fuel surcharge and a fuel rebate?
A positive adjustment is a surcharge when diesel rises above the contract base price. If diesel falls below the base price, the result can be a negative adjustment or rebate unless the contract applies a zero floor.
Does the calculator use UK or US gallons?
The MPG option uses the UK imperial gallon, equal to 4.54609 litres. Do not enter a US MPG figure without converting it first.
Should empty miles be included?
Only include empty, return or positioning miles if they form part of the agreed chargeable mileage. The commercial contract controls which miles qualify.
Are government weekly diesel prices live inside the tool?
No. Enter the current price manually so you can use the exact contract source, bulk diesel invoice, fuel-card price or government weekly average agreed with the customer.
Can I download the calculation?
Yes. Save recent calculations on the current device and download a detailed PDF or CSV record for quotations, invoice support and internal review.