Comparison
Co-oto or Excel + Splitwise/Tricount: which solution for sharing a car with people you know?
Bookings, mileage, fixed costs: what the spreadsheet doesn't track, and the point where a dedicated app changes the game.
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The essentials in 30 seconds
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A spreadsheet plus Splitwise/Tricount answers a single question: who owes how much to whom. It handles neither vehicle booking, nor mileage tracking, nor pro-rata fixed costs (based on the offerings as of August 2026).
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Fixed costs account for roughly two thirds of what a car costs: the TCS arrives at 74 Swiss centimes per kilometre for its 2026 reference car, the Automobile Club Association at around 36 euro cents. Sharing only the fuel leaves the majority of the real cost with the owner.
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A spreadsheet is still the right call in some cases: an occasional loan to a single driver, two users with naturally separate schedules, or a circle that values full control over its formulas.
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The switch usually happens at the same moment: several drivers, weekly usage, and weariness of the double entry.
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Co-oto brings it all into a single app: a booking calendar, odometer-based trips visible to both parties, and fixed costs split pro rata to usage, with no commission and no hardware box. Invited drivers pay nothing.
A spreadsheet paired with Splitwise or Tricount answers a single question: who owes how much to whom. Sharing a car raises three more: who has the vehicle when, what each trip really costs, and how to split insurance, taxes and depreciation between the people who use it.
For an occasional loan, the spreadsheet plus expense app duo does the job. As soon as sharing becomes regular, with several drivers, a private car sharing app like Co-oto replaces double entry, scheduling clashes and fragile formulas with a single tool. Here is the detailed comparison, figures included, and the cases where a spreadsheet is still the right call.
How people share a car with a spreadsheet today
The most common homemade method combines two tools. An Excel or Google Sheets table acts as the logbook: date, driver, starting odometer, ending odometer, amount owed. An expense-sharing app, Tricount or Splitwise, is then used to settle up. Anyone who has tried it knows the ritual: the link to the file is pinned in the group chat, everyone is supposed to log their trips when they hand back the keys, and at the end of the month someone copies the totals into the app to trigger the reimbursements. As long as everyone plays along, the system holds.
The spreadsheet: flexible, free, entirely manual
Excel and Google Sheets offer total freedom: every circle builds its own columns and formulas. That freedom comes with a maintenance cost. The templates available online are almost all designed for a one-off trip or for professional expense claims, rarely for a vehicle shared over the long run. So you have to build the calculation logic yourself, keep it up to date with every new bill, and train every new member to fill it in correctly.
Splitwise: solid for general expenses, limited on the free plan
Splitwise remains a benchmark for group expenses: roommates, trips, nights out. Since 2023, however, the free version has been limited to three expense entries per day, with ads. The Pro plan, around USD 5 per month or USD 40 to 50 per year depending on the offer (rates checked in August 2026), unlocks receipt scanning, charts, data export and currency conversion. Splitwise handles recurring expenses (monthly, annual) and splits by percentage or by shares. None of those functions covers mileage or vehicle booking.
Tricount: simple and free, stripped of several functions since version 8.0
Tricount, a Belgian app acquired by the bank bunq in 2022, claims roughly 16 to 17 million users. It remains free and very effective for settling shared expenses. Since the app was rebuilt (version 8.0), several features from the former Premium plan have disappeared: CSV and PDF export, personal mode, statistics and saved custom splits, some of which are announced as planned for a future update in the official help centre. Like Splitwise, Tricount ignores mileage and offers no calendar.
What Splitwise, Tricount and Excel do not handle for a car
No booking calendar
This is the first friction point once several drivers are involved. Neither Splitwise nor Tricount offers booking, and a "schedule" tab in a spreadsheet assumes everyone remembers to check it and fill it in. In practice, coordination drifts to WhatsApp, and double bookings are discovered on Saturday morning in front of an empty garage. Co-oto includes a booking calendar with owner approval (which you can switch on or off), recurring blocked slots, and a maximum booking duration.
No cost per kilometre, no pro-rata fixed costs
Expense apps split amounts that have been paid. A shared car, however, generates a cost per kilometre driven, on top of annual fixed costs (insurance, taxes, depreciation, parking space) that should be split according to how much each person actually uses the vehicle. Rebuilding that logic in Excel calls for formulas combining duration and mileage, to be updated with every new bill. In Splitwise or Tricount it is simply out of scope. In Co-oto, the owner enters the annual bills once; the app turns them into an hourly cost, charges each trip the share matching its duration, and adds the per-kilometre rate set for the vehicle.
No time-stamped trip history
A spreadsheet can be edited after the fact, without a trace. A time-stamped trip logbook showing who was driving, when, and with which odometer readings is a far more solid document when the tax authorities take an interest in how the vehicle is used. In Co-oto, every trip is visible to both the owner and the driver, which cuts down on disputes.
Double entry and the burden on the group "accountant"
Two tools means every trip is entered twice: one row in the spreadsheet, one expense in the app. And in most circles, one person ends up carrying the whole system: chasing latecomers, fixing formulas, checking balances. Our guide to private car sharing also points to the awkward moment when a member leaves, which often leaves frozen balances and a file nobody keeps up to date.
Why sharing only the fuel underestimates the real cost
Fixed costs account for roughly two thirds of what a car costs
This is well established on both sides of the border. In Switzerland, the TCS puts the 2026 cost of running its reference car (CHF 45,000, 15,000 km a year) at 74 centimes per kilometre: CHF 6,977 of annual fixed costs against CHF 4,135 of variable costs, about 63 % fixed. In France, the Roole car club put the average monthly budget at the end of 2025 at EUR 416, of which EUR 257 in fixed costs, a comparable proportion, and the Automobile Club Association estimates the full cost at around 36 euro cents per kilometre. With average annual mileage falling (around 11,000 km in France), every kilometre driven mechanically costs more. We set out the official rates and the real cost per kilometer, country by country.
What that means for your own sharing
Sharing limited to a tank of fuel leaves depreciation, insurance and taxes with the owner, which is to say the majority of the real cost. For an occasional favour between friends, that is fair. The balance breaks down when a brother, a neighbour or a roommate uses the vehicle every week. A fair split combines two components: a per-kilometre rate for usage, and a share of the fixed costs proportional to each person's use. That is exactly Co-oto's calculation model, with a simulator that shows the cost of a trip before you take it.
Comparison table: Co-oto against Excel + Splitwise/Tricount
Scroll the table horizontally.
| Criterion | Excel / Sheets | Splitwise | Tricount | Co-oto |
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| Price | Free | Free (3 entries / day); Pro ≈ USD 5 / month | Free | Free plan; Plus EUR 4.90 / month; Teams EUR 9.90 / month; invited drivers free |
| Booking calendar | DIY | No | No | Yes (approval, blocked slots, maximum duration) |
| Odometer-based trip tracking | Manual | No | No | Yes, visible to both parties |
| Cost per kilometre calculation | Formulas to build | No | No | Yes, with a trip simulator |
| Fixed costs split by actual use | Manual, fragile | No | No | Yes (pro rata to usage time) |
| Resettable statement per person | Manual | Partial | Yes | Yes, per driver |
| Receipt photos | No | Pro (OCR scan) | No (v8.0) | Yes |
| Vehicle location | No | No | No | Yes (last parking spot) |
| Multiple vehicles | Manual | Not applicable | Not applicable | Yes (1 on Free, 3 on Plus, 10 on Teams) |
| Excel export and statistics | Native | Pro | Removed (v8.0) | Yes |
| Time-stamped history | Editable | Yes | Yes | Yes |
| Commission on payments | None | None | None | None |
Comparison compiled in August 2026 from the vendors' public offerings. Splitwise prices in USD.
The cases where a spreadsheet (or Tricount alone) really is enough
A dedicated app is not justified in every situation. Three setups where the homemade method is still the right choice:
An occasional loan to a single driver
If you lend your car a few times a year to one person, a Tricount for fuel and a flat amount agreed in advance are plenty. Nothing to install, nothing to pay, nothing to maintain.
Two users with naturally separate schedules
A couple or two colleagues splitting the car between weekdays and weekends have no scheduling conflicts to arbitrate. A well-built spreadsheet, kept up with discipline, does the job.
The need for full control
A spreadsheet belongs to you: custom formulas, data you can export at will, no dependency on a vendor. If your circle includes an advanced Excel user happy to play accountant, that autonomy has real value.
The switch usually happens at the same moment: several drivers, weekly usage, and weariness of the double entry.
Co-oto: coordinating the use of a vehicle within a circle of trust
Built for people who already know each other
Co-oto equips circles that exist before the app: families, friends and neighbours, roommates, colleagues, associations, housing cooperatives. Peer-to-peer rental platforms answer a different need: connecting strangers, in exchange for a commission and background checks. Here, the trust already exists; only the organisation is missing.
No commission, no hardware box, and the car keeps its own insurance
No payment goes through Co-oto: reimbursements happen between you, exactly as they do today. There is no box to install: trips are entered from the odometer and the reading is visible to both parties. The vehicle stays covered by its usual insurance, which generally includes lending to people close to you; check your policy all the same, in particular any exclusive-driver clause. In Switzerland, our article on car sharing and insurance in Switzerland covers casco, deductible and bonus in detail.
Getting started takes a few minutes
The owner creates the vehicle, invites the circle by link or QR code, sets the per-kilometre rate and, if they wish, the annual fixed costs. Invited drivers pay nothing. The 21-day trial gives access to every feature with no automatic billing; the free plan then covers light usage (1 vehicle, 2 drivers in total, 5 trips a month), and the Plus plan at EUR 4.90 a month unlocks unlimited trips, recurring bookings and fixed costs included in the calculation.
FAQ: sharing car costs with people you know
How do you fairly split the costs of a car between friends or family?
By combining two components: a per-kilometre rate for usage (fuel, servicing, wear) and a share of the fixed costs (insurance, taxes, depreciation) proportional to how much each person uses the car. The TCS benchmarks in Switzerland or the Automobile Club Association figures in France give a useful starting point, to be adjusted for your own vehicle.
How do you calculate the cost per kilometre of a shared car?
Add up all the annual costs of the vehicle, fixed and variable, then divide by the annual mileage. For reference, the TCS arrives at 74 Swiss centimes per kilometre for its 2026 reference car, and the Automobile Club Association at around 36 euro cents. Co-oto's trip simulator applies that calculation automatically with your own settings.
Should you use Tricount or Splitwise for a shared car?
Both are fine for settling simple reimbursements, and Tricount has the advantage of being free with no entry limit. Neither handles vehicle booking, mileage tracking, or pro-rata fixed costs (based on their offerings as of August 2026). For regular sharing you therefore need to add a spreadsheet, with the double entry that implies.
Can you build an Excel sheet to share car costs?
Yes. At a minimum, plan for columns covering date, driver, starting odometer, ending odometer, kilometres driven and amount owed, plus a tab listing annual fixed costs. The weakness shows over time: formulas to maintain, forgotten entries, and no booking management at all.
Is sharing your car with family and friends taxable?
The general principle: as long as reimbursements do not exceed the costs actually incurred, there is no profit, so no income to declare. In France, the tax administration has confirmed this framework for cost sharing between private individuals (the co-consumption doctrine, in a ministerial answer published by the Senate in 2024). A precise record of trips and costs, such as the one kept in Co-oto, is exactly what demonstrates the absence of profit.
Can you lend your car to a relative without risk?
Lending the wheel to someone close is generally covered by the vehicle's own insurance, in Switzerland as in France. Check your policy on two points: any exclusive-driver (or named-driver) clause, and the excess that applies to an occasional driver. In an at-fault accident, the financial consequences (excess, and bonus-malus depending on the country) stay attached to the owner of the vehicle.
Which app should you use to share a car within a family or between roommates?
Look for three functions in one place: a booking calendar, odometer-based trip tracking, and a cost calculation that includes fixed costs. Co-oto combines them with no commission and no hardware box, with a Tricount-style statement you can reset at each reimbursement. A spreadsheet can carry you at the start; the need for an app appears as soon as the number of drivers grows.
What happens when someone leaves the circle?
With a spreadsheet and a Tricount, a departing member often leaves balances to reconstruct and an orphaned file. In Co-oto, each driver has their own statement, which the owner resets once payment is received: the departing member settles up, and the trip history stays archived on the owner's side.
On taxation in France, see the ministerial answer published by the Senate in 2024.
Ready to retire the spreadsheet and the double entry?
Co-oto is available on iOS and Android. Full 21-day trial, no commitment.