Vehicle log

Add your vehicles (with the odometer you start from), then log as you go: each fill-up or charge, each job done on the car, and costs such as insurance and tax. Everything is worked out from that.

How to use it

Overview — what needs attention across every vehicle, and for each one its odometer, average economy, running cost per mile or km and the total logged.
Fuel & charging — add a fill-up with the odometer, the fuel put in and what it cost (or the price per litre or gallon). Tick Filled to full when the pump clicked off. Economy is measured only from one full tank to the next: the fuel for that stretch is everything put in after the first full fill up to and including the second, so a partial fill in between adds its fuel to the next full one rather than giving a silly figure of its own. If you forgot to log a fill, tick I missed logging the fill before this on the next one and that stretch is left out instead of reading far too good. The chart shows each tank and a rolling average of the last five.
For an electric car or plug-in hybrid, add charging sessions with the kWh billed and, ideally, the odometer. Efficiency is the distance between sessions over the energy put back at the later one, so the first session only sets the starting point. The kWh your charger or the network bills includes charging losses (often 10–15 % at home on AC), so the figure here is lower than the car’s own display. That is your real cost. To compare with the car’s figure, set a loss to ignore under Vehicles & data.
Service & repairs — reminders for oil and filters, spark plugs, tyre rotation, brake fluid, coolant, the timing belt, the MOT or inspection and more, each with an interval by distance, time or both, whichever comes first. A bar shows how much is used; it turns amber at 85 %, red when it is due, dark red at 110 %. With only a distance set, the due date is projected from how far the vehicle has gone over the last year. Done restarts a reminder and adds it, with its cost and parts, to the history. Repairs, parts, tyres, insurance, tax and parking go in the history too.
Costs — the cost of ownership per vehicle: fuel, charging, each kind of work and cost, and depreciation (what you paid less what it is worth now), per mile or km, and spending by month.
VIN — decodes a 17-character vehicle identification number in the page and, if you ask, looks it up with NHTSA’s vPIC service.
Vehicles & data — vehicles' details, odometer readings for a vehicle you rarely fill, JSON backup and restore, CSV export of fill-ups, charges and history, and CSV import of fill-ups.

Choose the units under Units: distance in km or miles, fuel in litres or US or UK gallons, and economy in mpg (US), mpg (UK), L/100 km or km/L. A UK gallon is 4.546 litres and a US gallon 3.785, so the same car does 20 % more "mpg" in the UK: 40 mpg (UK) is 33.3 mpg (US) and 7.1 L/100 km. Load example data fills in a petrol hatchback, an electric car and a motorbike with a year of history to look around with.

The default service intervals

They are rules of thumb for a typical modern vehicle, to be replaced with your handbook’s figures: engine oil and filter every 15,000 km or a year; air filter 30,000 km or two years; cabin filter 20,000 km or a year; spark plugs 60,000 km; tyre rotation 10,000 km; brake fluid every two years; coolant every five; a timing belt 100,000 km or five years (some engines need it far sooner, some far later, and chains have no interval); and for motorbikes, chain cleaning and lubrication every 800 km and valve clearances every 24,000 km. "Severe" use — short trips, towing, dusty roads, a lot of idling — often halves the oil interval. Edit any reminder to set your own.

Decoding a VIN

The VIN is on a plate at the base of the windscreen, on the driver’s door pillar and on the registration document; OBD-II diagnostics can read it from most cars made since 2005 or so. The page checks it without sending it anywhere:

Structure (ISO 3779): 17 characters, never I, O or Q. The first three are the world manufacturer identifier (WMI), the next six describe the vehicle (VDS), and the last eight identify it (VIS).
Check digit: position 9 on North American VINs is a check digit (US 49 CFR 565). Each character becomes a number (letters A–H are 1–8, J–N are 1–5, P is 7, R is 9, S–Z are 2–9), each is multiplied by a weight (8 7 6 5 4 3 2 10, then 0 for the check digit itself, then 9 8 7 6 5 4 3 2), and the sum’s remainder after dividing by 11 is the check digit, with 10 written as X. A wrong check digit on a US or Canadian VIN almost always means a typing error. Many European makers do not use it, so a mismatch there means little.
Model year: position 10 is a code that repeats every 30 years (A = 1980 or 2010, Y = 2000 or 2030, 1–9 = 2001–2009 or 2031–2039; U, Z and 0 are never used). For North American cars and light trucks, a letter in position 7 means 2010–2039 and a digit means 1980–2009. Elsewhere the page takes the latest year that is not in the future. European makers are not required to code the year here.
Region, country and maker: the first character gives the region (1–5 North America, J–R Asia, S–Z Europe, and so on), the first two the country for the common ranges, and the WMI the maker for about 90 common ones. A 9 in position 3 marks a small maker, identified by positions 12–14 as well.

Look up with NHTSA vPIC sends only the VIN to the US National Highway Traffic Safety Administration’s free Product Information Catalog API at https://vpic.nhtsa.dot.gov/api/vehicles/DecodeVinValues/<VIN>?format=json, which allows calls from any web page. It returns the make, model, year, body, engine and plant as the maker reported them to NHTSA. It covers vehicles sold in the United States best; others may decode only partly. Save to a vehicle copies the VIN, make, model and year to the vehicle picked on the other tabs.

CSV import and export

Export writes fill-ups, charging sessions and the history as CSV in your current units. Import reads fill-ups from any CSV with a header row containing a date, an odometer (odometer, odo, mileage) and a fuel quantity (litres, gallons, volume, quantity) column. It also uses cost or total, price per unit, full or partial, missed, station and note columns where present. The units come from the header, such as Odometer (mi), Litres or UK gallons, or from your settings. Rows that match a fill already logged (same day, same odometer) are skipped. Exports from most fuel-log apps work after renaming a column or two.

Limits

The log is stored only in this browser (localStorage). Clearing site data, a private window, or another browser or device starts empty: export a JSON backup now and then. It is never sent anywhere and never goes into a link.
Economy is only as good as the fill-ups: pumps click off at slightly different levels, so single tanks scatter by several per cent and the average over many is what to trust.
The reminders do not know your vehicle’s maker schedule, and the projected due date assumes you keep driving as much as you did over the last year.
The built-in maker list is short, and a few country ranges are left out; vPIC fills those gaps for vehicles sold in the US.
Money is in whatever currency you type, with no conversion between vehicles.

Linking to an example

Share link copies a link with your units and the VIN on the VIN tab. Your log never goes into a link. A hand-written link can set these:

Parameter Meaning Example

Parameter	Meaning	Example
`vin`	A VIN to decode (open the VIN tab with `#vin`)	`vin=1HGCM82633A004352`
`dist`	Distance: `km` or `mi`	`dist=mi`
`vol`	Fuel volume: `L`, `galUS` or `galUK`	`vol=galUK`
`econ`	Economy: `mpgUS`, `mpgUK`, `l100` or `kmL`	`econ=l100`
`ev`	EV efficiency: `miKwh`, `kmKwh`, `kwh100` or `whMi`	`ev=kwh100`

vin

A VIN to decode (open the VIN tab with #vin)

vin=1HGCM82633A004352

dist

Distance: km or mi

dist=mi

vol

Fuel volume: L, galUS or galUK

vol=galUK

econ

Economy: mpgUS, mpgUK, l100 or kmL

econ=l100

ev

EV efficiency: miKwh, kmKwh, kwh100 or whMi

ev=kwh100

For example ?vin=1HGCM82633A004352#vin decodes a 2003 Honda Accord’s VIN, and ?dist=mi&vol=galUK&econ=mpgUK sets British units.