How do I forecast fleet fuel spend?

Estimate total miles, divide by average MPG to get gallons, then multiply by fuel price. You can add growth assumptions for miles, MPG, or fuel price to forecast monthly spend.

What inputs matter most for fuel budget accuracy?

Miles driven and fuel price usually drive the biggest swings. MPG matters too, especially when speeding, idling, or load factors change.

Can I create best/base/worst cases?

Yes. Use the scenario settings to change miles growth, MPG improvement/decline, and fuel price change to generate best/base/worst forecasts.

Fleet Fuel Spend Forecast Calculator (Free) | Moto Watchdog

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Fleet Fuel Spend Forecast Calculator (Free)

Forecast monthly and annual fuel spend using miles, MPG, and fuel price—then model best/base/worst scenarios and fuel price sensitivity.

Monthly forecast

Best / base / worst

Fuel price sensitivity

Inputs

Fleet size (vehicles)

Miles per vehicle per month

Average MPG (fleet)

Fuel price ($/gal)

Forecast horizon (months)

View

Miles growth (%/year)

MPG change (%/year)

Positive = efficiency improves, negative = worse MPG.

Fuel price change (%/year)

Include idling adder (% fuel)

Optional: add % fuel due to idling/inefficiency.

Fuel price sensitivity (± $/gal)

Miles sensitivity (± %)

Tip: If you’re building a budget, run a “worst case” with higher fuel price + higher miles + lower MPG.

Projected spend (monthly avg)

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Average across horizon

Projected spend (total)

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Across horizon

Projected gallons (total)

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Across horizon

Biggest drivers

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Scenario	Total spend	Delta

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Month	Miles	MPG	Fuel price	Gallons	Spend

How to use this forecast

Fuel budgets swing because of two things: miles and fuel price. MPG matters too—especially when driver behavior changes (speeding, idle, harsh driving).

Budgeting tips

Use a base case: current miles, current MPG, and current fuel price.
Run worst case: higher price + higher miles + slightly lower MPG.
Monitor monthly: compare actual to forecast and re-forecast quarterly.

Fuel Forecast FAQ

Should I forecast by month or by season?

Start simple with monthly. If seasonality is strong (snow routes, summer demand), increase miles in those months manually (export CSV and adjust).

How do I account for idling or route inefficiency?

Use the “idling adder” to add a % fuel overhead. For more precision, use the Idling Cost and Route Optimization tools.

What if I have multiple vehicle classes?

Run separate forecasts per class (light-duty vs heavy-duty) and combine totals. This is usually more accurate than a single blended MPG.

Disclaimer: Forecasts are estimates. Real-world MPG and miles vary with load, weather, traffic, and routes.