The meals have been eaten and washed down with a glass of wine.

Twenty minutes later, everyone needs the toilet. Cue, a long queue to use the aircraft toilets.

In the age of airline cost-cutting, replacing a toilet with a seat is far more attractive on the balance sheet.

So how many toilets are ‘enough’?

Methodology

Most people can manage without using the toilet on a short flight of an hour or so. In fact, many people can manage on a flight of 2 or 3 hours.

For this post I looked at four planes that operate long haul routes, where most passengers will use the toilets at least once during the journey:

Introduced Manufacturer Model Airline Seatguru 2006 Boeing 777-200LR Emirates Seat map 2007 Airbus A380 Emirates Seat map 2012 Boeing 747-8 Lufthansa Seat map 2014 Boeing 787-9 Virgin Atlantic Seat map

The rules

There are no US laws specifying minimum numbers of toilets on board planes.

There is also little guidance about recommended ratios of toilets to people elsewhere in the world.

To add some context, UK Health and Safety laws require a ratio of one toilet to start plus one more for each 25 people or part thereof. So in a workplace with 8 people, there would be a requirement for two toilets. In a workplace with 28 people, there should be three toilets, and so on.

The reality

All seats

Total Toilet Ratio Rank Plane Total Toilet:Seat Ratio Eco Toilet:Seat Ratio 1 2012 Boeing 747-8 (Lufthansa) 1:28 1:46 2 2014 Boeing 787-9 (Virgin Atlantic) 1:29 1:38 3 2006 Boeing 777-200LR (Emirates) 1:30 1:43 3 2007 Airbus A380 (Emirates) 1:30 1:43

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The Boeing 747-8 has one toilet for every 28 passengers, compared to just one toilet shared between 30 on the Airbus A380 and Boeing 777-200LR. The newer planes offer the best ratio of passengers to toilets.

These numbers are considering total toilets across all seat classes. The picture improves in first class where some passengers enjoy 1 seat between 4 people (Boeing 747-8 and 777-200LR). Which of course impacts the numbers for economy passengers. The worst toilet to seat ratio for economy passengers is found on the Boeing 747-8, with one toilet for every 46 passengers.

Toilet efficiency

Let’s assume on an 8 hour flight a passenger visits the toilet twice on each journey, with an average time in the toilet of 4 minutes (8 minutes total).

For this calculation I’m going to only consider economy seats, because, lets be honest, we already know first and business class travellers have it good!

Plane Time in toilet p/pax Total Pax mins in toilet total Each economy toilet use (mins) Toilet in use (8 hours ave) Toilet in use (2 hours ave) 2006 Boeing 777-200LR (Emirates) 8 1728 346 72.00% 288.00% 2007 Airbus A380 (Emirates) 8 3416 342 71.78% 284.67% 2012 Boeing 747-8 (Lufthansa) 8 2208 368 76.67% 306.67% 2014 Boeing 787-9 (Virgin Atlantic) 8 1816 303 63.06% 252.22%

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Overall the toilets on these aircraft are occupied between 63% – 72% of the flight, assuming they are open for use across the whole 8 hours. This equates to each toilet being occupied for around 5.5 hours in total.

That said, it’s not a perfect world. Most people tend to use the bathrooms on these types of flights about an hour after the first meal, and again in the final hour of the flight as it approaches its destination. Let’s assume that’s a 2 hour window.

Again, assuming passenger spend an average of 8 minutes in the toilet the numbers look a lot worse. The toilet utilisation is between 252% – 288%, meaning it is likely there will be someone in the toilet when you come to use it.

tl;dr

The worst toilet to seat ratio for economy passengers is found on the Boeing 747-8, with one toilet for every 46 passengers. At peak times, it’s very likely you’ll have at least two people queuing ahead of you to use the toilet.

Footnotes

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