The list already exists. It is called Bookings_2026.xlsx or lives as a calendar in Outlook, someone has kept it for years, and everyone knows their way around it.
What nobody has done is evaluate it. Yet those rows show where bookings overlap, which resource hardly anyone uses, and on which weekday everything happens at once.
This post shows what you can get out of an existing list before you change anything. How to prevent double bookings in future is covered in Avoiding double bookings. This one is about looking back.
One row per booking, with at least the resource, the start and the end. A header row helps but is not required. The check detects the columns itself and shows you what it read as resource, start and end. If something is off, you reassign the column.
For the analysis itself there is the free booking check, no sign-up needed. Copy and paste rows from Excel or Google Sheets, or import the file: .xlsx, CSV, text or the CSV export from your Outlook calendar, up to 5 MB and 2,000 rows per run. The analysis runs in your browser and nothing is uploaded.
If you would rather do the maths yourself, everything below can be built in Excel. It just takes longer.
The obvious case, and the most awkward one: two bookings on the same resource at the same time. A list that has grown over the years almost always contains some, usually from weeks when two people were entering bookings in parallel. If one booking ends exactly when the next begins, that does not count as an overlap.
The number matters less than the pattern. If overlaps cluster on one resource, it is either scarce or nobody is clearly responsible for it.
For each resource, the check divides the time it was occupied by the time it was available. Overlaps count once, so utilisation can never exceed 100 percent. You have to decide what "available" means: around the clock, or workdays only. The default for workdays is Monday to Friday, 7 am to 7 pm.
The difference is large. The same bookings might give 9 percent utilisation around the clock and 25 percent on workdays. For a seminar room the second number is the honest one, for a fire engine the first.
So never compare the figures with someone else's, only with each other: which of your resources is busy, which one sits idle.
If the van is in demand three times over on Tuesdays and sits empty on Fridays, you do not need a second vehicle, you need a different distribution. For halls and rooms this is the same question as with training slots.
Across the months you also see whether your season really runs the way everyone assumes.
Every list has them: an end before the start, a booking without a resource, a typo in the year, the same booking entered twice. The check flags these rows with a note and leaves them out of the totals. Entries without a time count as a whole day, from midnight to midnight. The "Problems only" filter shows just the rows you need to sort out.
That sounds like housekeeping. But these are exactly the rows that break the import into a new system later.
Three limits to keep in mind.
The list only knows what was entered. Someone who takes the van on the spur of the moment and writes nothing down does not show up. Low utilisation can also mean people are working around the list.
Rarely used does not mean unnecessary. The trailer that is needed four times a year is still worth its weight in gold the fifth time. The number is a reason to ask, not a decision.
Five rows are not statistics. For a reliable statement you need at least six months.
Before you think about a new system, it is worth looking at what you already have. The check takes two minutes, and it gives you the arguments you will need in front of the board or the administration anyway.
If you do switch afterwards, at least one problem disappears on its own: in a booking calendar, the same resource cannot be booked twice at the same time. The questions to settle before choosing are in Choosing a booking system. More calculators and templates are in the free tools.
Trying it costs nothing: no contract, no setup fee, 30 days free.