Friday afternoon, half past three. Someone on your team opens two screens side by side. On the left the rental system, on the right the accounting software. Invoice by invoice, the totals move from left to right. Or a CSV gets exported, imported, and everyone hopes all the lines came across. Or the numbers are simply typed over, with the quiet hope that no digit gets transposed.
Nobody thinks this is a good idea. Everybody knows it could be done differently. And yet it happens again every week, because it's "just how we do it".
If you want to grow, with more vehicles, more rentals or a second location, you need to ask yourself one question: does this Friday afternoon ritual grow with you? Because it does. Every extra rental is an extra line someone has to transfer.
The ritual nobody names
Double data entry isn't in any job description. It's called "quickly updating the books", "ticking off the payments" or "updating the calendar". It's small enough never to make it onto a management meeting agenda, and big enough to cost an afternoon every week.
At twenty rentals a week, that's an hour. At a hundred rentals a week across two locations, it's several people putting the same data into different systems at different moments. Nobody sees the total, because nobody does all of it.
What "how we do it" costs per year
The work feels small because you see it week by week. Work it out per year instead:
- hours per week × number of people × working weeks per year = hours of double entry per year
A worked example, explicitly hypothetical: three employees each spend an hour and a half a week re-typing, exporting and checking. That's 4.5 hours a week. Over 46 working weeks, that's 207 hours a year, more than five full 40-hour working weeks. Hours in which nobody helps a customer, checks out a vehicle or handles a damage claim.
Multiply the result by your own hourly cost and you have the amount you pay every year to move data that already exists. And that's before you count the errors.
Four places where your rental data lives apart
In most rental businesses, the same rental lives in four places. Every handover between them is a moment where things can go wrong.
The rental system
This is where everything starts: the reservation, the contract, check-out and check-in, the extra kilometres and the damage. The rental system knows the most, but if it doesn't connect, that knowledge stays locked inside it.
The accounting software
The invoice has to reach the accounting software, with the right ledger account, the right VAT rate and the right amount. An invoice adjusted after a damage settlement has to go in twice. Forget that correction and your books no longer match your rental records.
The payment provider
The customer pays online, the money is in the bank, but in the rental system the booking is still open. So someone lays bank statements next to a list and ticks things off. Until then, a customer who paid long ago sometimes still gets a reminder.
The calendar
A reservation is confirmed but isn't yet in the calendar of the colleague who has to prepare the car. Or a rental is extended and the calendar lags behind. The result is a vehicle that isn't ready, or an employee who comes to the branch for nothing.
One transposed digit
Double data entry doesn't just cost time. It costs certainty. An invoice of €1,380 entered as €1,830 only shows up at the quarterly VAT return or when the customer calls. A CSV whose last ten lines didn't import may never show up at all.
The more rentals, the more handovers, and the bigger the chance that one of them goes wrong somewhere. That isn't about how careful your team is. People simply aren't built to copy hundreds of numbers flawlessly every week. Software is.
So the principle is simple: every piece of data is captured once, where it originates, and then flows automatically to the systems that need it.
What a connected Friday looks like
How RentVisie handles this is on the integrations page. The rental software connects with Exact, Twinfield, Mollie, Stripe, Google Calendar and Outlook. With Exact Online that's a real-time connection: invoices, payments and journal entries are synchronised automatically. Payments through Mollie, by iDEAL, credit card or SEPA, come back to the invoice they belong to. Calendars are updated automatically. If you use a system that isn't on the list, you can build your own connection through the API and export your data to Power BI, Excel or other tools.
How it works today at many rental businesses
- transferring invoice totals to the accounting software on Friday afternoon
- laying bank statements next to open bookings on Monday morning
- adding reservations to the calendar by hand
- hunting for the difference between two systems at the end of the quarter
How it works when the systems are connected
- the invoice is in the accounting software the moment it is created
- an online payment is synchronised with the invoice, no tick list needed
- a confirmed reservation is in the calendar
- Friday afternoon belongs to customers, vehicles and growth again
We wrote earlier about chasing invoices and about what a spreadsheet really costs your rental business. Double data entry is the same problem in different clothes: work that only exists because systems don't talk to each other.
Why CSV export is no longer a feature
For years, "export to CSV" was on the feature list of rental software. It meant: the data can get out, the rest is your problem.
That era is ending. Rental businesses already work with their accounting package, their payment provider and their calendar, and they won't drop those for their rental software. Software that doesn't connect to the tools an operator already uses asks that business to build its processes around the software. Businesses that want to scale increasingly choose the opposite: software that fits how the business already works.
So when choosing rental software, don't just look at what the system can do, but at what it talks to. An accounting integration isn't a nice-to-have. It's the difference between a system that grows with you and a system that costs you an afternoon every week.
Moving data is a symptom
The hours your team spends moving data between systems aren't a workflow. They're a symptom of systems that don't talk to each other. And unlike most symptoms in a business, this one has a straightforward cure.
Start counting this week. Ask everyone on your team how much time they spend each week re-typing, exporting, importing and ticking off. Fill in the formula. Then you'll know what the double-entry tax costs your rental business per year, and what you get back when you abolish it.
Frequently asked questions
What is double data entry in a rental business?
Double data entry means manually transferring data that already exists in another system, for example invoice totals from the rental system to the accounting software, payments from the bank to the bookings, or reservations to the calendar. It often goes unnoticed, spread across several employees and several moments in the week.
How do I calculate what double data entry costs my rental business?
Multiply the hours per week an employee spends re-typing, exporting and checking by the number of employees who do it and by the number of working weeks per year. Multiply the result by your hourly cost. Add the time spent finding and fixing errors as well.
Can rental software connect to Exact and Twinfield?
Yes. RentVisie connects with Exact and Twinfield. The Exact Online connection is real-time: invoices, payments and journal entries are synchronised automatically, so you no longer have to enter them into your accounting by hand.
Which systems can I connect to my rental software?
RentVisie connects with Exact, Twinfield, Mollie, Stripe, Google Calendar and Outlook. For other systems there is an API, which lets you connect your own systems, your website or BI tools. Custom development is also possible.
Isn't a CSV export enough?
A CSV export gets the data out of one system, but someone still has to put it into the other, check that everything came across and fix errors. With a few rentals a week that's manageable. With a growing fleet that work grows at the same pace, and so does the chance of errors.
Explore the live demo. See how a reservation, invoice and payment come together in one system, without anyone re-typing numbers on a Friday afternoon.
Explore the live demo