- How is MPG calculated?
- MPG (miles per gallon) is calculated as: miles driven ÷ gallons added. Miles driven is the odometer reading at the current fill-up minus the odometer at the previous fill-up. For example, if you drove from 45,000 mi to 45,312 mi (312 miles) and added 11.2 gallons, your MPG = 312 ÷ 11.2 = 27.9 MPG. The first fill-up in your log cannot show an MPG because there is no prior reading to compare against.
- Is my data saved? Will it disappear if I close the browser?
- Yes — your data is saved in your browser's LocalStorage and persists across sessions. It will remain until you clear your browser's site data or use the delete options in the app. Because storage is local, use the CSV export feature to back up your records or to transfer them to a new device. No data is ever sent to a server.
- Can I track multiple vehicles?
- Yes. Use the "Add vehicle" button at the top to add as many vehicles as you like. Each vehicle has its own independent fuel log and service history. Switch between vehicles using the dropdown selector at any time. All data is stored separately per vehicle.
- What is the difference between a full tank and partial fill?
- A full tank fill-up refills the tank completely, which gives an accurate MPG calculation (all the fuel from the previous full fill to this one was consumed over the measured distance). A partial fill is when you add some fuel without topping off — MPG cannot be accurately calculated for partial fills because you don't know exactly how much fuel was in the tank at the start. Partial fills are still logged for cost tracking purposes, but are excluded from the MPG chart.
- How do service milestones work?
- When you log a service entry and set a "next service due" odometer or date, the app shows this as a milestone in the Service tab. The app compares the due mileage against your latest odometer reading (from the most recent fuel log entry) to calculate miles remaining. Items within 500 miles are flagged as "soon" in orange; items past due show in red. This lets you glance at the app and instantly know what's coming up.
- How do I export my data for taxes or resale documentation?
- Go to the Summary tab and click one of the CSV export buttons. "Export Fuel Log" downloads a CSV with every fill-up (date, odometer, gallons, price, MPG). "Export Service History" includes all maintenance records with costs. "Export All" combines both into a single file. Open the CSV in Excel, Google Sheets, or Numbers to print, filter, or share. Many buyers appreciate a documented service history, and the fuel log is useful for mileage deduction records.