Bathtub buying guide: how to choose the right bath
Reviewed by the Beliani Content Team · Updated August 2026
A bath is one of the few things in a home that is bought once and lived with for decades, and it is also one of the hardest to change your mind about once the floor is tiled. Length, width and material are decided in that order, because the room fixes the size and the size narrows the material. This guide covers the measurements that matter, what each material is actually like to use, and the checks that stop a bath arriving that cannot be fitted.
In short
How do I choose the right bath?
Start with the space, then choose the material. The standard straight bath measures 1700 x 700 mm, with lengths sold from 1400 to 1900 mm and widths from 700 to 800 mm, so measure the clear wall run first and pick the nearest standard length that still leaves room for fitting and tiling. Acrylic suits most homes because a 1700 mm bath weighs roughly 25 to 35 kg empty, while cast iron weighs 80 to 150 kg empty and can reach 350 to 450 kg once filled with water and a bather. Whatever type you choose, allow about 700 mm of clear floor space in front of the bath.
- Which storey the bathroom is on, and whether the floor is timber or solid
- Whether you will shower over the bath, which calls for extra width
- Who uses it, including children and anyone who needs a lower rim
- Whether the taps mount on the bath, the wall or the floor
- Your hot water capacity, since a full bath holds 180 to 215 litres
How to measure before you choose a bath
Measuring is the one stage where an error cannot be corrected later. A rigid bath cannot be trimmed, and a 50 mm shortfall means sending it back.
- Measure the wall run where the bath will sit, at floor level and again at about 550 mm above the floor. Walls are rarely parallel, so use the smaller of the two figures.
- Measure from that wall to the nearest fixed obstacle. Subtract the width of the bath you are considering and check that at least 700 mm of clear floor space remains in front of it.
- Note how far the existing waste sits from each wall. A bath with its waste at the same end costs nothing extra to fit, while moving the outlet means lifting the floor.
- Measure door widths, stair turns and any tight corner between the front door and the bathroom. A 1800 mm bath has to travel in one piece.
- Choose the closest standard length below your clear wall run, leaving room for fitting and tiling.
Always size down, never up
If your clear wall run is 1680 mm, a 1700 mm bath will not go in, and no amount of adjustment will make it. Drop to 1600 mm and you gain 80 mm for the fitting, the tiling and the tolerance in the plaster. Buyers lose more baths to this single miscalculation than to any other measuring error.
Which bath shape fits your bathroom
Shape decides how much usable floor the bath leaves behind, which matters more in a small room than the length does.
Straight
Fits an alcove, costs least to plumb
Sold from 1400 to 1900 mm long and 700 to 800 mm wide, with 1700 x 700 mm as the default across most of the UK market. It sits against one wall, uses standard pipework positions and leaves the rest of the room free.
Freestanding
Needs space on every side
Allow at least 100 to 150 mm at each end so it does not look wedged in, and 200 to 300 mm behind if you want to reach round with a mop. Pipework usually runs up through the floor, so it has to be planned before the floor is finished.
Corner
Shorter, wider, frees a wall
Typically 1200 to 1600 mm along each side and 900 to 1400 mm wide. The extra width makes it easier to bathe children, but the diagonal front edge takes up more of the room's centre than the footprint suggests.
Back to wall
The freestanding look without the gap
Finished on the front and sides but flat at the back, so it sits tight against the wall. It keeps standard wall plumbing and removes the strip of floor behind a freestanding bath that is awkward to clean.
Shop now: freestanding bathtubs and corner bathtubs
Which bath material works best for daily use
Material sets three things at once: how heavy the bath is, how long the water stays warm, and how the surface behaves after ten years of cleaning.
| Material | Weight empty, 1700 mm | Heat retention | Surface and repairs | Best suited to |
|---|---|---|---|---|
| Acrylic | About 25 to 35 kg | Moderate, and warm to first touch | Scratches show, but light marks polish out | Upper floors and most family bathrooms |
| Enamelled steel | About 30 to 45 kg | Low, and cold to first touch | Hard and glossy, but a chip exposes steel that can rust | Heavy daily use where weight still matters |
| Cast iron | About 80 to 150 kg | Highest, so water stays warm longest | Very hard enamel lasting decades, but chips need professional repair | Ground floors and period bathrooms |
| Mineral composite | About 80 to 100 kg | High, close to cast iron | Usually matt, and marks can be sanded out | Contemporary freestanding baths |
Wall thickness is the specification that separates a good acrylic bath from a flexing one. Look for 5 mm acrylic with a reinforced base, and 2 to 3 mm on enamelled steel, which stops the base moving underfoot when you step in.
Can your floor take the weight?
One litre of water weighs one kilogram, so a filled 1700 x 700 mm bath carries roughly 200 kg of water before anyone gets in.
A filled acrylic bath with a bather typically totals around 300 kg, spread along the length of the bath and shared across several joists. A filled cast iron bath reaches 350 to 450 kg, and a large model can exceed that.
The load is worth checking with a builder or engineer in two situations: a cast iron or composite bath on an upper timber floor, and any freestanding bath standing on four small feet, which concentrates the whole load into four contact points rather than spreading it. Ground floors and solid floors rarely raise a question.
Taps, waste and overflow: what to check
Baths are sold both drilled and undrilled, and the two are not interchangeable once the bath is in the room. Confirm the tap hole count before ordering, because a drilled bath cannot take floor-mounted taps and an undrilled one cannot take deck taps without drilling.
Where holes are drilled, 180 mm between centres is the most common spacing for bath taps, and tap hole diameters usually fall between 22 and 35 mm. Match these to the taps rather than assuming they will line up.
Freestanding baths need the tap decision made before the plumbing is set. Wall-mounted spouts fix the bath's distance from the wall, since the spout has to reach over the rim, while floor-mounted taps let the bath sit further out but require the supply to come up through the floor in an exact position.
Shop now: bath taps
What the European standards on a bath mean
Three standards cover baths sold across Europe, and a specification sheet that names them tells you the product has been tested rather than simply described.
- EN 14516 sets the requirements and test methods for baths for domestic use, covering cleanability and durability of the finished surface
- EN 232 fixes the connecting dimensions of baths, which is what allows standard waste fittings and tap ware to fit regardless of manufacturer
- EN 263 covers the cast acrylic sheet that acrylic baths are formed from
Waste and overflow fittings are covered separately under EN 274-1, so a bath supplied without a waste can still be fitted with any compliant kit.
How much space to leave around the bath
Plan at least 700 mm of clear floor space in front of the bath, measured from the outer edge to the nearest wall or fixture. This is the figure UK bathroom planning guidance uses for all fixtures, and it is the difference between drying yourself comfortably and turning sideways to do it.
For a built-in bath, leave 50 to 100 mm of clearance around the rim where it meets tiling, so silicone can be cut back and renewed without damaging the surface. For a freestanding bath, a room narrower than about 2.5 m will usually look and work better with a built-in or back-to-wall model.
Read more: turning your bathroom into a home spa
What to check before buying
Confirm the clear wall run and the room depth against the exact external dimensions of the bath you have chosen, not the nominal size on the listing. Check the waste position matches your existing outlet, or budget for moving it. Confirm whether the bath is drilled for taps and how many holes it has. Check the stated capacity in litres against your hot water supply, since a 200 litre bath is of limited use if the cylinder cannot fill it. If the bathroom is upstairs and the bath is cast iron or composite, get the floor looked at before the order goes in rather than after it arrives.
Frequently asked questions
How long does a bath last?
An acrylic bath in normal family use lasts around 15 to 20 years before the surface dulls beyond polishing. Enamelled steel and cast iron last far longer, often 50 years or more, because the enamel surface wears very slowly. The failure point is usually a chip in the enamel rather than the bath itself.
Can I shower over a bath?
Yes, but standing comfort depends on width. A 700 mm bath is narrow to stand in, so choose 750 to 850 mm at the shower end, or a shaped shower bath that widens at one end. You will also need a bath screen and a flat, non-tapered standing area in the base.
Is a double-ended bath better than a single-ended one?
A double-ended bath has the waste and taps in the centre and a sloped back at both ends, so two people can recline facing each other. It needs more length to be comfortable, typically 1700 to 1800 mm, and it is a poor choice for showering because there is no flat standing end.
How do I clean an acrylic bath without damaging it?
Use a soft cloth with warm water and a mild liquid detergent, then rinse and dry the surface. Avoid scouring powders, abrasive pads and solvent-based cleaners, which leave fine scratches that trap dirt and dull the finish. Light scratches in acrylic can be polished out with a proprietary acrylic polish.
Does a larger bath cost more to run?
Depth affects running cost more than footprint does. A deep 1800 x 750 mm bath can hold around 213 litres to the overflow, while a shallower 1800 x 800 mm model holds about 182 litres despite the larger footprint. Check the stated capacity against your hot water cylinder before assuming a bigger bath can be filled comfortably.
