Calculate per-mile surcharge rates based on fuel prices and MPG.
Fuel Surcharge Per Mile
$0.000
Total Trip Surcharge Amount
$0.00
function calculateFSC() {
// 1. Get input values
var currentPrice = parseFloat(document.getElementById('currentFuelPrice').value);
var basePrice = parseFloat(document.getElementById('baseFuelPrice').value);
var mpg = parseFloat(document.getElementById('truckMpg').value);
var miles = parseFloat(document.getElementById('tripMiles').value);
// 2. Validate essential inputs
if (isNaN(currentPrice) || isNaN(basePrice) || isNaN(mpg)) {
alert("Please enter valid numbers for Fuel Prices and MPG.");
return;
}
if (mpg <= 0) {
alert("MPG must be greater than 0.");
return;
}
// 3. Calculation Logic
// The standard formula: (Current Fuel Price – Base Fuel Price) / MPG
var priceDifference = currentPrice – basePrice;
// If current price is below base, usually surcharge is 0 (or a rebate, but standard is 0)
if (priceDifference 0) {
totalAmount = surchargePerMile * miles;
}
// 4. Update the Display
var resultsDiv = document.getElementById('resultsArea');
var rateDisplay = document.getElementById('surchargeRate');
var totalDisplay = document.getElementById('totalSurcharge');
resultsDiv.style.display = 'block';
// Standard in logistics is often 3 decimal places for rates, 2 for totals
rateDisplay.innerHTML = "$" + surchargePerMile.toFixed(3);
if (totalAmount > 0) {
totalDisplay.innerHTML = "$" + totalAmount.toFixed(2);
} else {
totalDisplay.innerHTML = "$0.00 (Enter distance for total)";
}
}
How to Calculate Fuel Surcharge Rate
In the logistics and trucking industry, fuel costs are one of the most volatile expenses carriers face. To protect against sudden spikes in diesel prices without constantly renegotiating freight rates, carriers and shippers utilize a mechanism known as the Fuel Surcharge (FSC).
This guide explains how to calculate the fuel surcharge rate manually, ensuring transparency between shippers and carriers.
What is a Fuel Surcharge?
A fuel surcharge is an additional fee added to the linehaul freight rate. It fluctuates based on the national or regional average price of diesel fuel. When fuel prices rise above a predetermined "base" level, the surcharge kicks in to cover the excess cost. Conversely, if fuel prices drop, the surcharge decreases.
The Fuel Surcharge Formula
While some contracts use complex percentage tables, the most accurate and common method for calculating FSC is the "Pass-Through" method. This formula determines the surcharge on a cents-per-mile basis.
Fuel Surcharge Rate = (Current Diesel Price – Base Fuel Price) ÷ Average MPG
Understanding the Variables:
Current Diesel Price: Usually derived from the Department of Energy (DOE) National Average Diesel Price, updated weekly.
Base Fuel Price: The threshold price agreed upon in the contract. This represents the fuel cost already factored into the standard freight rate. A common historical standard is around $1.20 to $1.25 per gallon, though this varies.
Average MPG: The average fuel economy of the truck. While modern trucks may achieve 7.0+ MPG, many FSC contracts standardize this figure (often at 6.0 MPG or 6.5 MPG) to simplify calculations.
Example Calculation
Let's look at a realistic scenario to see how the numbers work in practice.
Variable
Value
Current DOE Diesel Price
$4.50 per gallon
Base Fuel Price (Contracted)
$1.25 per gallon
Truck Average MPG
6.5 miles per gallon
Trip Distance
1,000 miles
Step 1: Find the difference in fuel price.
$4.50 (Current) – $1.25 (Base) = $3.25 per gallon increase.
Step 2: Divide by the MPG to get the rate per mile.
$3.25 ÷ 6.5 MPG = $0.50 per mile.
Step 3: Calculate the total surcharge for the trip.
$0.50 per mile × 1,000 miles = $500.00 total surcharge.
Why Use a Variable Fuel Surcharge?
Using a mathematical formula rather than a flat fee benefits both parties:
Fairness: Carriers are reimbursed exactly for the increased cost of fuel, rather than making a profit on the surcharge.
Flexibility: Rates adjust automatically week-to-week based on the DOE index, removing the need to re-quote shipments constantly.
Transparency: Since the formula uses public data (DOE prices), there is no ambiguity about how the fee was derived.
Conclusion
Calculating the fuel surcharge rate is a critical skill for freight brokers, owner-operators, and fleet managers. By defining a clear base rate and MPG standard in your contracts, you can use the calculator above to instantly determine the correct surcharge for any given lane.