The Golden Ratio of Bathrooms

There’s been a recent trend among the ultra-rich and occasionally-famous, who have taken to flaunting golden bathrooms and toilets. But two hundred years ago, luxury didn’t require fine bathrooms. It’s been said that Versailles was built with surprisingly few toilets despite having hundreds, if not thousands, of guests and residents at any given time.

So, what is the value of a bathroom, and what is the optimum number of bathrooms to have in a property?

Bathrooms vs. Asking Price: The Golden Ratio

It might sound like a superfluous question, but when it comes to designing and building properties, details like this one can make all the difference. If you build too many bathrooms, then you’re wasting money on additional construction costs and fittings, not to mention lowering the GDV of the development with less valuable space (compared to bedrooms and living rooms). It obviously doesn’t make much sense to build a property with one bedroom and three bathrooms. But with too few bathrooms, the property can also be much less attractive.

We analysed over 70,000 properties based on the number of bedrooms and bathrooms to find the ideal ratio.

As you might expect, we found a positive relationship between the number of bathrooms and prices: generally speaking, the more bathrooms a property had, the more it was worth. Typically, this is because more bathrooms also means more bedrooms, therefore greater overall square footage. By analysing the price curve, we’ve discovered that the optimum number of bathrooms to build in a property is one less than the total number of rooms. A 6-bedroom house should have 5 bathrooms, a 5-bedroom house should have 4 bathrooms, and so on.

The trajectory of prices for the 6-bedroom property most clearly demonstrates this principle. The added value of every additional bathroom (without exceeding the maximum) was £81,000, on average. Thus building up to the optimal number of bathrooms — five in this case — added an average of £262,000, or 67 percent to the value of the property. However, if we follow the graph to the addition of a sixth bathroom in a six-bedroom unit, the asking price plummets significantly to £113,000.

So, when considering how to make best use of additional space, you will have to build more porcelain thrones than Louis XIV did, but you don’t necessarily have to gild them.