Fuel sets the traffic and the store sets the profit, and each side keeps its own scoreboard. The operators who do well are the ones who watch the right handful of numbers and read them together. These are the KPIs that matter, what each one tells you, and how they connect.
The fuel-side numbers
- Fuel margin (CPG). Cents per gallon. Track it both gross and net of card fees, and know which one a benchmark uses; published industry averages are gross. It swings daily with the market.
- Fuel volume. Gallons sold. Volume and margin trade off, so they have to be read as a pair.
Pricing the pump is its own discipline, covered in how to price fuel at a gas station. The short version: cheap fuel that fills the lot is only a win if those drivers also walk inside.
The inside-store numbers
- Inside gross margin. The store's margin percent. NACS data for 2025 shows fuel brought in 65% of industry sales dollars but under 40% of gross profit dollars; the inside store earned the majority of the profit on roughly a third of the revenue.
- Basket size. The average sale inside. The number to grow.
- Inside-to-fuel ratio. How well fuel traffic converts into store sales.
The relationship between thin fuel margin and fat inside margin is the heart of the model, laid out in convenience store profit margins.
The control numbers
Margin you earn can be given right back, so two more KPIs guard the bottom line:
- Shrink as a percent of sales. The loss from theft, error, and waste. Covered in loss prevention.
- Labor as a percent of sales. Your largest controllable expense inside the store.
Read them together
The mistake is judging the store on one number. High volume with thin margin can be healthy if it feeds a strong basket. A great margin means nothing if shrink and labor eat it. The skill is holding all of them in view at once, tracked over time, so a soft trend shows up while you can still fix it.
Where FastDragon helps
FastDragon C-store pulls fuel and inside sales, margin, shrink, and labor into one place, so these KPIs are sitting in front of you instead of scattered across a POS report, a fuel report, and a spreadsheet. You see the whole store at a glance and catch the trend early.
Answers to common questions
What is a good fuel margin for a gas station?
Fuel margin is measured in cents per gallon (CPG), and it swings with the market. The 30 to 50 cents-per-gallon industry averages reported in recent years (NACS/OPIS) are gross margin, before credit-card fees; fees then take several cents off what you keep. Watch your own CPG trend against your volume, since the two trade off, and be clear which basis you are looking at.
How do you calculate fuel margin in cents per gallon?
Take the street price, subtract taxes and the delivered cost of the fuel, and you have gross CPG. Subtract card fees to get net CPG; because cards charge a percentage of the sale, the fee per gallon climbs as pump prices rise. Track both figures and only compare a benchmark on the same basis it was reported in.
Why track inside sales separately from fuel?
Because they behave differently. Fuel moves in huge volume at pennies of margin, while the store earns a far richer margin on smaller sales. If you only watch total sales, a healthy fuel month can hide a weak store, or the other way around. Splitting them tells you where the money actually comes from.
What is basket size and why does it matter?
Basket size is the average sale value inside the store. It is a quick read on whether customers are buying more than one item and whether merchandising and promotions are working. Growing the basket, getting the fuel-only customer to also buy a drink and a snack, is one of the highest-leverage things a c-store can do.
How often should gas station KPIs be reviewed?
Fuel margin deserves a daily look because rack cost and street prices move every day. Inside margin and basket size work on a weekly rhythm. Shrink only shows its true size at physical inventory counts, typically monthly, and labor percent is best checked against each schedule before it posts, since it is the one cost you set in advance.