How to plan a bathroom (2024)

Do you need help on how to plan a bathroom? Check our bathroom layouts to make the most of the space, and our recommendations on designing a bathroom.

Regardless of the size of your room, making the most of the space you do have is key to achieving maximum comfort and practicality. This is why how you lay out your bathroom is so important: when you get it right, functionality and interior design work together in perfect harmony.

In this article, we'll take a look at how to best use your available space to get the perfect bathroom layout:

Minimum bathroom dimensions

How to plan your bathroom layout

Minimum toilet dimensions
Minimum washbasin dimensions and installation height
Minimum dimensions for bathroom cabinets and mirror installation height
Minimum bath and shower dimensions
Bath and shower tap installation height
What about the bathroom door?
Where to put plug sockets in your bathroom

5 sample bathroom layout plans

Layout plan for a small 1.5 m2 bathroom
Layout plan for a 3.7 m2 bathroom
Layout plan for a 4 m2 bathroom
Layout plan for a rectangular 4 m2 bathroom
Layout plan for a 6.38 m2 bathroom

Minimum bathroom size

The function in the bathroom should prevail over the shape. Therefore, in all bathroom planning, there are minimum sizes that must be respected so that our project is a usable space.

The minimum size of a bathroom which includes a toilet and a basin is 140cm x 95cm in a rectangular floor plan, and 120cm x 120cm in a square floor plan, with a hinged door. This space can be reduced if we opt for compact or embedded elements, as well as sliding doors.

The minimum size for a small bathroom with en suite shower or bathtub, toilet and basin, and as long as a sliding door is included, will be 150cm x 150cm for an en suite bathtub bathroom and 135cm x 150cm for an en suite rectangular shower bathroom.

But before drawing the plan for our bathroom, following these steps is recommended.

Plan the special needs of the space and the people who will make use of it.
Count on the bathroom equipment we need beforehand, since it is mostly static, and it involves an installation prior to its placement. Some questions that need to be answered are the following: Will we have built-in elements such as toilet cisterns? Do our bathroom sizes make us opt for compact models? What will the bathroom be like? With one or two bowls? Floor standing, countertop or recessed? Will a shower or bathtub be installed? Will we count on a bidet?
Comply with the regulations on the evacuation of toilets by CTE (technical building code), whose objective is to optimise the water evacuation network and the use of energy resources:
1. The layout of the network must be simple and optimum so that the water flow is by gravity.
2. Connect the equipment to the drainpipes. If this is not possible because of the design, its connection to the toilet hose is allowed.
3. The distance of the drain trap to the drainpipe must not be greater than 2m and the branches that are connected to the drain trap must have a maximum length of 2.5m, with a gradient between 2-4%.
4. The elements with an individual trap, namely: basins and bidets; must have a maximum 4m distance to the drainpipe, with gradients between 2.5 and 5%. The gradient should not exceed 10% in either bathtubs or showers.
5. The drain toilet drain to the drainpipes will be carried out directly or through a 1m maximum connection hose.
6. Basins, bidets and bathtubs must have an overflow.
7. No facing drains must be placed or supported on a common pipe.
8. The joints of the drains to the drainpipes must have the greatest possible inclination, not less than 45º.
9. When the individual trap system is used, the drainage branches of the sanitary equipment must be connected to a bypass pipe which flows into the drain, or if this is not possible, then into the toilet hose, with a registrable head with a screw tap.
10. Pumped drains should be avoided.

Incorrect distances between sanitary elements lead to uncomfortable bathrooms

Minimum sanitaryware sizes

The toilet and bidets must have a minimum space of 70cm in width and 120cm in length. If they are next to a wall, the minimum free space should be 20cm, and if there is an element on their side, they should not be placed less than 15cm away for greater usability.

One way to further optimise the space is offered by the use of toilets with wall-concealed cisterns, inside the partition, or the models of compact and wall-hung toilets, which are smaller than the standard ones. The installation height of the wall-hung toilets will be 45cm from the ground.

The latest bathroom designs bank on joining toilets and bidets to become a single element, such as smart toilets and sanitary spray hand showers. These options turn out to be ideal in small bathrooms and projects in which the number of sought-after elements to be installed is reduced to the max.

Minimum sizes and height where the basin should be installed

The variability of formats and sizes in basins is very wide, although the standards of a single bowl are usually about 60cm wide and 45cm deep. The minimum space for its countertop will be 70cm wide.

As far as double-bowl basins are concerned, they are standard 90cm and their countertop should have a minimum of 120cm, with a distance between both taps of at least 60cm.

The installation height for the highest functionality is 85cm from the ground level, although it can be adjusted to the height of the person. With regard to countertop basins, this size will be taken to place the highest part of the element.

Minimum installation sizes for bathroom furniture and the height for installing a mirror

Regardless of the ergonomic features depending on the people, the general recommendations state that the bathroom furniture should be installed 85-90cm from the ground, whereas the mirror is either 35cm above the basin countertop or 15cm above the taps.

Minimum bathtub and shower installation sizes

In the variability in the models, the standard size of a bathtub is 200cm x 70cm, with a height of 42cm.

Showers offer greater versatility, and there are options of cut-out (shower) trays that allow higher adaptability to the needs of the space. In any case, the minimum shower space will be at least 70cm x70cm, and its door or entrance space will leave a free space of 60cm.

The height at which the bathtub and shower taps should be installed

With regard to the bath taps, they should be installed about 70cm from the ground, bearing in mind the overall height of the bath, whereas in the showers, the height will be 1.40cm from the shower tray.

What should the bathroom door be like?

An optimal option for saving space is the use of sliding doors, but in the case of making use of a hinged door, a free gap of 62cm, which is the most used size for bathroom doors, should be provided.

Where should plugs be installed in the bathroom?

According to the regulations for the installation of electrical appliances in bathrooms, it is important to understand the position by which the lights are arranged in a bathroom.

The IP acronym stands for “Protection Index” and it is always followed by two characters. These two numbers refer to the level of protection, and furthermore, the fact of opting for accessories with the correct index of protection is key, depending on their sought-after placement in the bathroom.

The diagram shows a bathroom divided into four clear areas: 0,1, 2 and 3. Area 0/0 area is inside the bath or the shower. Any product which may be used in this area must be of low voltage (maximum 12v) and be rated at least IP67, which is the total immersion test.

Area 1 is the area above the bathtub or shower at a height of 2.25m from the ground. A minimum index of protection of IP44 is required in this area. If we are dealing with a product with 240v voltage, its circuit must be separated and protected with residual current device of 30mA.

Area 2 is 0.6m outside from the ground up to a height of 2.25m, along the upper part of area 1 up to 0.75m and the remaining area of drawing up a semicircle of 0.60m above the basin, starting from the water outlet point. The index of protection in this area must be at least IP44.

Area 3 is everything that is outside any of the previous areas 0,1 and 2 (subject to specific limits) and in which no water engine is used. This area requires an IP-X1 index of protection.

In addition to the above, if there was a probability of installing any product near a water outlet, regardless of the situation in areas 1,2 and 3, it would have to be provided with at least an IP65 index of protection.

5examples of bathroom layout plans

Whether dealing with large sizes or a small bathroom, a proper bathroom element layout will be necessary to make space usability easier with very inch optimised.

In order to make bathroom planning easier, our experts suggest 5 layout plans to design a bathroom that will help you to make the most of the space.