The formula
Surcharge per job = (current price − baseline price) × gallons per month ÷ jobs per month
Baseline price = the fuel price your current rates were built on.
That's the whole calculation. Everything else on this page is about getting those four inputs right and choosing how to present the result: as dollars per job, cents per mile, or a percentage of the invoice.
Worked example
A small hauling company set its prices when diesel was $3.50 a gallon. Diesel is now $6.30. The trucks use about 421 gallons a month across 120 jobs, and the average job is $250.
| Step | Calculation | Result |
|---|---|---|
| 1. Price increase per gallon | $6.30 − $3.50 | $2.80 |
| 2. Extra fuel cost per month | $2.80 × 421 gal | $1,178.80 |
| 3. Extra cost per job | $1,178.80 ÷ 120 jobs | $9.82 |
| 4. As a % of the average job | $9.82 ÷ $250 | 3.9% |
So a $9.82 surcharge per job (or a 3.9% increase) recovers the added fuel cost exactly. Without it, about $1,179 a month comes straight out of profit.
Getting the inputs right
- Baseline price: use the fuel price when you last set your rates, not the lowest price of the year. If you don't know it, use the EIA weekly average from that month.
- Current price: use what you're actually paying, from fuel card statements or receipts, or the EIA weekly average if your fuel tracks it closely.
- Gallons per month: total fuel spend for a normal month ÷ price per gallon. Include equipment (mowers, chippers, generators) if it shares the fuel budget.
- Jobs per month: count the unit you bill: jobs, visits, stops, loads, tows, or hours. Use a normal month, not your busiest.
Three ways to present it
| Method | How it's calculated | Best for |
|---|---|---|
| Flat $ per job | Extra monthly fuel cost ÷ jobs per month | Service businesses with similar-sized jobs |
| Cents per mile | Price increase per gallon ÷ miles per gallon | Hauling, moving, towing, long-distance work |
| % of invoice | Fuel share of revenue × (current ÷ baseline − 1) | B2B accounts, mixed job sizes, contracts |
Per mile: a truck that gets 8 MPG burns 1/8 of a gallon per mile, so a $2.80 increase adds $2.80 ÷ 8 = $0.35 per mile.
Percentage: in the example above, fuel at the baseline price was 421 × $3.50 = $1,473.50 on $30,000 of monthly revenue, a 4.9% fuel share. Fuel is now 80% more expensive ($6.30 ÷ $3.50 − 1), so the surcharge is 4.9% × 80% = 3.9%. That's the same answer as the per-job method, expressed differently.
Tying it to a public index
Customers accept surcharges more readily when they can see they follow a public number. The most common reference in the U.S. is the Energy Information Administration's weekly average retail diesel price. A tiered table sets the surcharge for each price band and updates as the index moves.
Ready-made table
MarginShock's fuel surcharge table shows the surcharge percentage at every price level for different fuel shares, with this week's EIA price highlighted.
Open the fuel surcharge table →Common mistakes
- Padding the surcharge. A surcharge that obviously exceeds fuel costs gets noticed, and it damages trust in your base prices too.
- Forgetting equipment fuel. Mowers, chippers, generators, and reefers can be a big share of total fuel.
- Using your busiest month. Peak-month jobs spread the cost over more work and understate the per-job figure for the rest of the year.
- No exit. Say when the surcharge will be reviewed or removed. Surcharges that never come down feel like price increases in disguise.
- Ignoring contracts. Recurring agreements often require written notice before prices change.