In short :
- Look for a box with plates or glasses inside and water lines hitting them.
- Water across the whole box means it’s safe on any rack.
- Water on the top half only means top rack only.
- A line through the box means keep it out of the dishwasher entirely.
- No symbol at all?
- Treat it as hand wash only.
The symbol for dishwasher safe in the UK is a square or rectangular box containing plates or glasses with diagonal water lines or droplets falling onto them. That’s the short answer. The longer answer matters more, because the same little box has several variations, and misreading one can turn a favourite mug into a cracked relic or warp a plastic lunchbox beyond use.
Manufacturers across the UK and Europe follow broadly the same icon conventions, so once you know what to look for, you can decode almost any item in seconds. Below you’ll find exactly how each variation looks, where to find the marking, and which items should never go near a dishwasher regardless of what any symbol says.
How to Read the Dishwasher-Safe Symbol: The Three Main Variations
The core icon is always the same: a box, dishes inside, water hitting them. What changes is where the water goes and whether there’s a line through the box. Those details carry all the meaning.
General dishwasher safe (any rack)
Water droplets or diagonal lines cross the entire box and cover all the plates or glasses. This means the item can go on either the top or bottom rack. It’s the most permissive version of the symbol.
Concrete example: A standard ceramic dinner plate from a supermarket often carries this full symbol on its base. It can sit in the bottom rack without concern because ceramic tolerates the higher temperatures and direct water pressure down there.
Top rack only
Here, the water lines or diagonal streaks hit only the top portion of the plates or glasses. The bottom half stays dry. This is the symbol that catches most people out, and it’s the one to look for on plastics.
Concrete example: A plastic food storage container with a top-rack-only marking will often survive hundreds of cycles on the upper rack but can distort, cloud, or lose its lid seal after a few runs in the bottom rack, where the heating element sits close by.
Not dishwasher safe
Same icon, but with a diagonal line or an X slashed through the box. That’s your stop sign. Hand wash only.
Concrete example: A wooden chopping board or a cast-iron pan marked this way isn’t being fussy — the dishwasher will strip seasoning from cast iron and cause wood to crack and warp through repeated soaking and drying cycles.
Where to Find the Symbol on UK Items
Look on the base first. Most ceramics, glassware, and plastic containers print or emboss the symbol on the underside, sometimes faintly. Turn the item over and check near the centre or around the rim.
If the base is blank, check these spots:
- Inside the lid of plastic containers (very common for food storage boxes)
- On the care label of anything with a fabric or silicone component
- On the original packaging or the manufacturer’s care instructions, if the item is new
- Etched into glass, which can be nearly invisible until you tilt it toward the light
Concrete example: Glass tumblers frequently have the symbol etched near the base rim rather than printed. Holding the glass at an angle under a bright light reveals a faint marking that’s invisible from straight above.
If you genuinely can’t find a symbol anywhere, treat the item as hand-wash only until you can confirm otherwise. That cautious default saves more dishes than it costs in effort.
Items That Should Stay Out of the Dishwasher, Symbol or Not
Some materials are risky even when a marking suggests otherwise — or when the marking has worn off entirely. A quick mental checklist helps:
| Item type | Why it’s risky | Best approach |
|---|---|---|
| Wood (spoons, boards) | Cracks, warps, splits along the grain | Hand wash and dry immediately |
| Cast iron | Strips seasoning, causes rust | Wipe clean, re-oil occasionally |
| Insulated travel mugs | Heat damages the vacuum seal | Hand wash the body |
| Sharp knives | Harsh cycle dulls blades and can chip edges | Hand wash and dry straight away |
| Non-stick pans | Coating degrades faster under high heat | Hand wash to extend life |
Concrete example: An insulated flask that starts rattling or stops keeping drinks hot is often the victim of a dishwasher cycle — the vacuum between the walls has failed, and no symbol on the base will warn you in advance.
Frequently Asked Questions
What is the symbol for dishwasher safe in the UK?
A square or rectangular box showing plates or glasses being sprayed with diagonal water lines or droplets. If the water covers all the dishes, the item is safe on any rack. If it only hits the top, it’s top-rack only. A line or X through the box means hand wash only.
What is the symbol for dishwasher safe on Tupperware?
Plastic food storage containers typically carry the top-rack-only version: a box with water lines hitting just the upper portion of the dishes. That’s because the base of a dishwasher runs hotter and closer to the heating element, which can warp or cloud plastic. Check the underside of the container and the inside of the lid, since markings vary by range.
How to check if something is dishwasher safe?
Turn the item over and look for the box symbol on the base, lid, or care label. No symbol at all? Assume hand wash only. When in doubt, a single test run on the top rack with a piece you can afford to lose tells you more than guesswork — but only do this with items you’re willing to risk.
What does the symbol for a dishwasher-safe top rack look like?
It’s the same box with dishes inside, but the diagonal water lines or droplets appear only across the top section, leaving the lower part of the dishes untouched. That asymmetry is the giveaway: water reaching only the top means the item belongs on the upper rack.
The Bottom Line
So, what is the symbol for dishwasher safe in the UK? A box with dishes and water lines — and the details tell you the rest. Water everywhere means any rack. Water on top only means top rack. A slash through the box means keep it out entirely.
Spend ten seconds checking the base of a new item before it goes in the machine. That small habit prevents most of the warping, clouding, and cracking that people blame on “bad quality” when it’s really a misread symbol. For a fuller guide covering care labels, material behaviour, and loading strategy across the whole kitchen, a more complete article on the general theme is available on the site.
Put it into practice : How much dishwasher salt should I use?
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