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Your Fleet Model
Your Inputs
Build your fleet baseline
Add your fleet size and fuel price to see your estimate. Adjust the pre-filled mileage and fuel efficiency if needed.
Fleet and fuel
Fine-tune the model
Optional inputs improve the estimate. Every default is editable.
Estimated Annual Value
What your fleet could recover
Your estimate appears here
Fill in the two highlighted fields — fleet size and fuel price — to model what your fleet could recover.
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Transparent by design
A fuel cost calculator that shows its working.
A fleet fuel cost calculator estimates annual fuel spend from vehicle count, distance, fuel economy and price per litre. This model then separates direct cash savings from productivity value, so cheaper fuel is never mixed invisibly with time savings.
Fuel cost formula
In UK units: annual fuel cost = (annual miles ÷ MPG) × 4.54609 × price per litre. In metric units: annual fuel cost = (annual km ÷ 100) × L/100km × price per litre. Example: a 20-vehicle fleet driving 20,000 miles each at 32 MPG pays about £80,000 a year with petrol at £1.40 per litre.
Three honest scenarios
A single optimistic number hides uncertainty. Conservative, average and cutting-edge cases vary each saving lever independently and keep optional behaviour savings off until you choose to include them.
Fuel-price assumption
Rally customers save more than 5% on fuel on average. The model uses 3% in the conservative case, 5.5% in the average case and 8% in the cutting-edge case to show a wider honest range.
Rally cost, included
The model deducts an editable illustrative subscription per active card from direct savings. Service-fee savings only cover the current network, transaction and service fees you enter.
Every lever, across all three cases
These are the model's reduction or prevention rates. Your inputs stay constant while the assumptions change, making the range easy to audit.
| Savings lever | Conservative | Average | Cutting-edge |
|---|---|---|---|
| Cheaper open-loop fuel | 3% | 5.5% | 8% |
| Service fees removed | 75% | 90% | 100% |
| Less detour fuel | 40% | 65% | 85% |
| Fuel fraud and misuse | 25% | 50% | 75% |
| Spend-control behaviour | 0.5% | 1.5% | 3% |
| Admin and reporting | 25% | 50% | 70% |
| Fewer accounting errors | 50% | 75% | 90% |
| card-wait days avoided | 50% | 80% | 100% |
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Eight value levers
Savings are more than pence per litre.
Closed networks, manual reporting and slow card replacement create costs outside the headline fuel price. The calculator keeps each lever visible.
Open-loop fuel prices
Drivers can choose lower pump prices instead of being routed to one network or a provider-set list price.
No hidden service fees
Model network, transaction and service charges separately from Rally's visible card subscription.
Wider coverage
More accepted stations means fewer detours, fewer declined transactions and less driver frustration.
Fuel fraud controls
Real-time limits and transaction visibility can reduce misuse without assuming every suspicious transaction disappears.
Optional behaviour change
Limits and feedback may change purchasing habits, but this lever stays off until you explicitly include it.
Cleaner accounting
Receipt capture and automated coding reduce the corrections hidden inside month-end close.
Faster card access
Apple Pay can reduce dependence on physical-card shipping for supported drivers and use cases.
Reporting time
One fleet ledger replaces exports, invoice matching and repeated reporting across providers.
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Questions
Fuel Cost Calculator FAQs
Multiply annual distance by the number of vehicles, convert distance and fuel economy into litres used, then multiply by the average price per litre. In UK units the formula is miles divided by MPG, multiplied by 4.54609 litres per UK gallon and then by fuel price.
It depends on current pump or list prices, fees, routes and controls. Rally customers save more than 5% on fuel on average, but this calculator uses a 3% conservative case, 5.5% average case and 8% cutting-edge case rather than presenting one guaranteed result.
Yes. An editable illustrative monthly cost per active card is deducted from direct savings. The result shows that cost as a separate negative line so it is not hidden.
Cheaper fuel and removed fees affect cash directly. Admin and driver time only become financial value when your team can redeploy those hours, so the calculator reports them separately before combining them into total annual value.
A wider acceptance network reduces detours to an approved station. That can save fuel, vehicle wear and paid driver time while making routes less frustrating for employees.
You enter the share of fuel spend you believe is lost to fraud or misuse. The model assumes only 25% of that leakage is prevented in the conservative case, 50% in the average case and 75% in the cutting-edge case.
Yes. Switch the calculator from miles and MPG to kilometres and L/100km. You can also switch between pounds and euros.
No. It is an illustrative planning model. Actual savings depend on fuel prices, routes, fleet adoption, current fees, driver behaviour and the accuracy of the data you enter.
Divide the price in pence per litre by your MPG and multiply by 4.54609. At £1.40 per litre and 32 MPG, fuel costs about 19.9 pence per mile. This calculator reports cost per mile automatically from your fleet's own efficiency and fuel price.
Yes. Enter your fleet's real average fuel efficiency — for example roughly 40 MPG for diesel vans or 8 to 10 MPG for HGVs — and every cost and saving lever scales with it. Mixed fleets can use a weighted average.
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Turn the model into a real plan