IP ratings explained (checker included)

Every IP rating is just two digits, and each digit has one job. The first (0 to 6) tells you how well the enclosure keeps solids out, from the back of a hand right down to fine dust. The second (0 to 9) covers water, from a light vertical drip up to a high-pressure, high-temperature jet. Higher means tougher, and honestly, that's the whole system.

What does IP65 mean?

IP65 means the enclosure is completely dust tight (the 6) and protected against low-pressure water jets from any direction (the 5). In plain terms: British weather can do its worst, and so can a hose from a few feet away, and the fitting won't care. That's exactly why it's stamped on half the floodlights in Britain. What IP65 is not is submersible, for that you need a 7 or an 8 as the second digit.

Reading any rating works the same way, three seconds flat:

1. First digit, solids. 0 to 6, from no protection at all up to fully dust tight.
2. Second digit, water. 0 to 9, from vertical drips up to high-pressure, high-temperature jets.
3. See an X? That digit simply wasn't tested. It's not a claim of zero protection, it's no claim at all.

IP44 vs IP65: what's the actual difference?

These are the two ratings you'll weigh up most often, and it's not one small step between them, it's a jump on both digits at once.

Rule of thumb: if the fitting only ever gets splashed, IP44 does the job. If it takes driven rain, a pressure washer or a dusty workshop, it wants IP65. When in doubt, the price gap is small enough that IP65 is the cheap insurance.

First digit: solid objects and dust

Second digit: water

The ratings you'll actually fit

In practice, the same handful of ratings turns up on job after job. Here's where each one earns its keep:

What IP rating for a bathroom?

The one that catches people out. Zones 1 and 2 need a minimum of IPX4, rising to IPX5 where water jets are used for cleaning. Zone 0, inside the bath or shower tray itself, needs IPX7. Not sure where one zone ends and the next begins? My bathroom electrical zones guide maps the whole lot out, and once you know what you're fitting, the downlight spacing calculator will sort the layout in seconds.

What IP rating for outdoor lights and sockets?

Sheltered positions, under an eave or inside a porch, get away with IP44. Anything genuinely exposed, a gable end, a garden wall, anywhere the jet wash reaches, wants IP65. Outdoor sockets are typically sold as IP66-rated enclosures, and it's worth telling the customer that the rating on the lid only holds while the lid is actually shut. Ground-recessed lights that flood after heavy rain want IP67, and anything permanently underwater, pond pumps and submerged pool fittings, needs IP68.

EV chargers and other outdoor kit with their own installation instructions? The manufacturer declares the rating and the mounting requirements, so work to their documentation rather than a chart, mine included. Where a location pushes past the everyday stuff, wash-down bays, plant rooms, agricultural buildings, BS 7671's section on external influences and the manufacturer's data are the final word, not a blog table.

• An X is not a zero. IPX4 means the solids digit simply wasn't tested, the water protection claim still stands in full.
• Don't pay for protection you don't need. IP68 strip in a dry lounge is money down the drain, quite literally the only place it would matter.
• A rating is only as good as the install. Botch a gland, pinch a seal or leave a knockout open and the IP65 on the box is fiction. The rating describes the enclosure as tested, not your workmanship.
• Working on an older install while you're at it? Keep my wiring colours UK reference open in the next tab, old red and black cores still lurk behind plenty of bathroom pull cords.