Days until empty
0days
From an empty cassette.
Waste each day
0L / day
Flush litres into the cassette.
Waste this trip
0L
Planning estimate only.
Empties needed
0empties
For the trip length you set.
For this trip
Empty stops for the trip length you set.
Start from a preset
Saved on this device
How to use
- Choose a preset if you want a head start, or keep the defaults.
- Set people and how many days you are away.
- Say whether you have a cassette or a fixed black tank, and type the litres.
- Edit flushes if your habits differ. Totals update as you type. Refresh the page: your numbers stay on this device.
FAQ
How often should I empty the cassette?
There is no single rule. This page uses flush litres — a planning figure, not how full the cassette “feels”. A typical 15–20 L cassette on a careful weekend for two can last several days. A busy family week often needs more than one empty. Empty at a proper service point when you can, and before it is full. Smell and site rules matter as much as the litre count.
What is the difference between a cassette and a black tank?
A cassette is a removable toilet tank, usually about 15–20 litres on UK leisure vans (Thetford-style). You slide it out and empty it at a service point. A fixed black tank is plumbed in, often much larger, and emptied through a dump valve. Most UK coachbuilt and van conversions use a cassette. Pick the one you have and type the litres.
What size is a typical UK cassette?
Thetford-style cassettes are often about 17–20 L. The litres are usually printed on the tank. This page defaults to 18 L. Type your real size if you know it — the field will not snap back while you type.
Does this count wee and solids, or only flush water?
Only flush water. Real waste takes a bit more room, and a chemical starter dose or rinse can add a litre or two. Treat the days as a starting plan and empty before the cassette is full.
Where should I empty it?
At a proper motorhome service point, aire, or campsite cassette point. Never on the ground, in a hedge, or down a household drain. If you are unsure, ask the site or use a published dump-point list.
Why might this differ from the Tanks page?
The Tanks page plans fresh, grey and cassette together, and it reads flush litres from the Water page. This page is only about empty stops, and it keeps its own people and flush numbers after the first visit. Use Tanks for a wild-camping stretch; use this page when you just want cassette empties.
What does “Cassette now” mean?
How full the cassette is at the start. 0% is empty — the usual “just emptied” start. 50% means you are already half full, so you have fewer days until the next empty.
Is this a design or a guarantee?
No. This is a planning estimate only. It is not a design, a waste test, or a promise that the cassette will last. Empty at proper points — never on the ground.