Common Bath Sizes: How Big Is a Bathtub?

Different Types & Dimensions

Bathtubs come in countless shapes and sizes. When people speak of the “shape” of a bathtub, they generally mean its outer shape, not the inner form of the tub. The two can – but do not have to – be identical. The stated dimensions also usually refer to the outer shape. If you know these, you will also know whether the bathtub fits into your bathroom.

There is not only the typical rectangular bathtub. Other shapes have also increasingly become popular and provide relaxation. Despite all this variety, there are still standards and, based on these, approximate standard dimensions. Until 2007, DIN 18022 applied to “Kitchens, bathrooms and WCs in residential buildings”, and this is still used as a point of reference today.

Bathtub sizes are generally divided into:

• Standard bathtubs / full-length baths (approx. 170–180 x 75–80 cm)
• Compact bathtubs (approx. 114–130 x 70–80 cm)
• Corner bathtubs (approx. 135–150 x 135–150 cm)
• Multi-person bathtubs / whirlpool tubs (approx. 180–230 x 180–230 cm)

Depending on the height of the tub, there are further versions such as sit-in baths with a door, freestanding bathtubs or those with a particularly ergonomic inner shape (body-shaped tubs). Special bathtubs with a shower zone are also possible, in some cases with low-barrier access.

Lying Comfortably in the Bath: Which Size Is Ideal?

How large a bathtub needs to be for you to disappear comfortably into warm water beneath a layer of bubbles naturally depends largely on your height. For a particularly relaxing bath, the width should be chosen so that your shoulders fit inside. As for the length, the rule is this: if you can fully stretch out your legs while seated, the bath will be comfortable. However, the tub should not be too long either, so that you can brace yourself and do not “float”.

So that you can relax and warm up in your personal oasis of wellbeing, you can use the dimensions of a standard bathtub of around 175 x 75 cm as a guide. This ideal bathtub size applies both to freestanding bathtubs and to rectangular tubs.

A useful rule of thumb is:

• Length: your height from neck to foot in cm
• Width: shoulder width plus 5–10 cm

Also crucial for lying comfort: does the bathtub have a backrest slope or not? The side on which the slope is positioned and the shape of the edges inside the tub also play an important role in how comfortable the bath is.

How Deep Is a Standard Bathtub?

For standard bathtubs, you will often find a height specification of between 40 and 59 cm. This always refers to the height of the tub itself and does not correspond to the maximum fill height of the bathtub. Around 10 cm should be deducted from the height as overflow protection.

In a whirlpool tub, the depth can even be up to 80 cm. This means that, even while sitting, you can immerse yourself comfortably up to your shoulders.

When buying a bathtub, you should also pay attention to the stated filling capacity: 140 to 245 litres are easily possible. How much water it holds depends not only on the dimensions, but also on the angle of the tub wall. Multi-person tubs can hold more than 400 litres.

How Much Space Does a Bathtub Need in the Bathroom?

When planning a bathroom, make sure to allow enough space for a bathtub. For a freestanding bathtub, the room should be at least 12 m² in size. For space-saving standard tubs, you should allow around 2 m² for the bathtub alone. The more unusual the tub, the more space you should allow for it. Only then can a beautiful bathtub really come into its own.

With suitable decoration or attractive bathroom textiles, you can create a small (or large) wellness retreat that impresses not only through its function, but also through its look.