A wobbly, cracked, or stained toilet seat is one of those things you put up with for far too long. Replacing one takes about 15 minutes, costs £15–£40 for a decent seat, and makes a surprisingly big difference to how your bathroom looks and feels. It’s genuinely one of the easiest DIY jobs in the house.
Measuring for a New Seat
Toilet seats aren’t one-size-fits-all. You need to measure your toilet bowl to get the right shape and size:
- Shape — is your bowl round or elongated (oval)? Most UK toilets are round/D-shaped. Measure from the front of the bowl to the centre of the fixing holes at the back. Standard UK round bowls are about 420–430mm; elongated bowls are 450–470mm
- Width — measure the widest point of the bowl. Standard is about 350–365mm
- Fixing hole centres — measure the distance between the centres of the two fixing holes at the back of the bowl. The vast majority of UK toilets use a standard 155mm centre-to-centre spacing, but check yours — a few older toilets vary
When in doubt, a universal-fit seat with adjustable hinges covers most standard toilets. Screwfix’s toilet seat range includes dimensions for each model.
Types of Toilet Seat
| Type | Price Range | Pros | Cons |
|---|---|---|---|
| Plastic (polypropylene) | £10–£20 | Cheap, lightweight, easy to clean | Can flex, feels basic |
| Thermoset plastic | £20–£40 | Solid feel, won’t flex, scratch-resistant | Heavier, cracks if dropped hard |
| Wood (MDF/solid) | £25–£60 | Warm to sit on, premium feel | Heavier, finish can wear, swells if seal damaged |
| Soft-close | £20–£50 | No slamming, quieter, hinge mechanism | Mechanism can wear out after years |
| Quick-release | £25–£50 | Seat lifts off hinges for easy cleaning | Slightly more expensive |
The best value choice for most people is a thermoset soft-close seat with quick-release hinges. The soft-close stops slamming (essential if you have children), and quick-release means you can pop the seat off for thorough cleaning around the hinges — where bacteria builds up.
Types of Fixing
Top Fix
Top-fix seats attach from above — you tighten bolts from the top of the bowl. These are the easiest to fit and the most common on modern toilets. The bolts drop through the fixing holes and are tightened with a wing nut or expanding fitting underneath, but all the tightening is done from above with no need to reach underneath the bowl.
Bottom Fix
Bottom-fix seats use bolts that you tighten from underneath the bowl with a nut. They’re common on older toilets and are more fiddly to fit because you need to reach under the back of the bowl — which, depending on the toilet position against the wall, can be awkward.
Check what your current seat uses before buying a replacement, or buy a seat that comes with both fixing options (many do).
Step-by-Step: Removing the Old Seat
- Locate the fixings — look at the back of the bowl where the seat hinges are. You’ll see plastic caps, bolt heads, or wing nuts
- Remove plastic caps — if present, prise them off to reveal the bolt heads underneath
- Unscrew the fixings — for top-fix, unscrew the bolts from above. For bottom-fix, hold the bolt head on top and unscrew the nut underneath
- Lift off the old seat
Dealing with Stuck or Rusted Fixings
This is the part that turns a 5-minute job into a 30-minute job. Metal fixings on older toilets corrode and seize solid. If the bolts won’t budge:
- Spray with WD-40 or penetrating oil and wait 10–15 minutes
- Use pliers or an adjustable spanner on the nut while holding the bolt with a screwdriver
- If completely seized, hacksaw through the bolt between the bowl and the nut. Wrap the bowl with masking tape first to protect the porcelain from the saw blade
- As a last resort, use an oscillating multi-tool with a metal cutting blade — it’s the fastest and most controlled way to cut a seized bolt
This is why many modern toilet seats use plastic fixings — they don’t corrode. When fitting your new seat, use the plastic fixings supplied with it, not metal ones.
Step-by-Step: Fitting the New Seat
- Clean the mounting area — scrub around the fixing holes and the back of the bowl with bathroom cleaner. This might be the first time you’ve seen under the old hinges — it won’t be pretty
- Position the seat — place the new seat on the bowl and align the hinge holes with the bowl fixing holes. The seat should be centred on the bowl with equal overhang on each side
- Insert the fixings — drop the bolts through the hinges and into the fixing holes
- Tighten evenly — alternate between the two bolts, tightening a little at a time. Over-tightening can crack the porcelain bowl, so stop when the seat is firm and doesn’t rock. Hand-tight plus a quarter-turn is usually enough
- Check alignment — sit on the seat and check it doesn’t slide sideways. If it does, loosen the fixings slightly, reposition, and retighten
- Replace any decorative caps — snap them over the bolt heads for a clean finish
Maintenance Tips
- Tighten fixings every 6–12 months — they work loose over time from the rocking motion of use
- Clean around the hinges weekly — use the quick-release feature if your seat has one
- Don’t use bleach-based cleaners on the hinge mechanisms — they can degrade the damper mechanism in soft-close seats
- If the soft-close mechanism slows down or stops working, the dampers may need replacing. Check with the manufacturer — many sell replacement hinge sets
Replacing a toilet seat is one of those five-minute jobs that improves your daily life disproportionately. There’s no reason to put up with a cracked, wobbly, or stained seat when the fix is this simple and cheap.
