Not microwave safe
The item is not meant to be used in a microwave oven.
Easily confused with
How to read it
It is the maker’s microwave icon, usually wavy lines, with a cross through it. Mepal says it uses the crossed-out icon when the material a product is made from isn’t meant to be heated that way, and that many of its products carry it. No standard defines the mark. The US Food and Drug Administration gives two reasons a container is kept out of a microwave: some plastics can be melted by the heat of the food inside, and metal pans and aluminium foil reflect microwaves, which cooks food unevenly and can damage the oven.
Also searched as: crossed out microwave symbol, no microwave symbol, not microwave safe symbol.
These describe what each mark means and who defines it. Most are makers’ own icons rather than a standard, and the same mark can mean slightly different things on different brands. What a particular dish, pan or container can be used for is set by its maker, in its care and use instructions.
Words and missing marks
Some makers print words instead: Pyrex says its airtight canisters are not designed for use in the microwave. Others leave the mark off. Sistema says its products without the microwave symbol can’t be used in a microwave.
Read next
- Next in Kitchenware symbolsOven safeThe maker says the item can go in an oven, often up to a stated temperature. Makers draw their own oven icon; it isn’t a standard symbol.
- The same shape in Medical and emergency emblemsAED signA white heart with a lightning flash through it, on a green square, marks where an automated external defibrillator (AED) is. It is the universal AED sign approved by the International Liaison Committee on Resuscitation (ILCOR) in 2008, and sign E010 in ISO 7010.
More kitchenware symbols
The same shape elsewhere
Browse symbols drawn with crosses, curves and waves or squares and rectangles.
Sources
- What do the symbols and specifications on a product mean?, Mepal, Microwave symbol
- FAQs, Sistema Plastics, Can I microwave food in your products?
- Microwave Oven Radiation, U.S. Food and Drug Administration, Microwave ovens and cookware
- Frequently Asked Questions, Carlisle Transportation Products (The Carlstar Group), Are airtight canisters microwave safe?
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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