Best microwave 2026: which one fits your worktop with the space its maker asks for, from small to combination

A 20 litre microwave is 43.4 to 45.5 cm wide and 31.5 to 35.8 cm deep, according to the spec sheets of the four in this guide. A 25 litre model goes up to 47.6 by 38.7 and a 28 litre one to 51 by 45. Five more litres cost about two centimetres of width; going from 25 to 28 costs three and a half of width and six of depth. Those are the figures that decide whether it fits, and they are exactly the ones missing where you buy.

And there is a second measurement almost nobody checks. LG's UK owner's manual asks you to «allow at least 20 cm from the top, 20 cm from the sides, and 20 cm back of the oven for proper ventilation», plus 8 cm from the front edge so it cannot tip and a surface more than 85 cm high. On that sum, the 47.6 cm appliance needs a space 87.6 cm wide. If yours is going on a worktop under wall units, we would point out that the deciding figure is not the litres: it is the depth plus the air behind, where the same manual asks for the same 20 cm as at the sides.

Many microwaves sold in the UK carry a letter next to the watts on the rating label. Sharp's owner's manual for its R-82STM explains where it comes from: «The heating category (a letter A to E) was developed by MAFF (Ministry of Agriculture, Fisheries and Food) with microwave oven and food manufacturers and indicates the ability of the oven to heat small quantities of food (up to 500g [1lb 2oz])». It measures how fast a small portion heats, not the output on the rating plate, and that is why the same manual lists that 900 W model as category D.

So the watts and the letter answer two different questions, and the watts are the ones every listing gives. What the higher figure changes is time, and LG writes it in its own UK manual for the 1,000 W MH6535GIS: «The setting of the cooking time should be shorter than common microwave ovens (700 W, 800 W) due to the relatively high output power of the product». If a pack gives times for 800 W and yours is 700 W, it needs longer; at 1,000 W, less.

The 700 W on a microwave is not what it draws: it is what it delivers to the food. That is the output power, measured with a published method, the standard IEC 60705, whose fifth edition dates from 13 November 2024 and also covers microwaves with grill and combination models. LG prints it in its own UK manual, at the foot of the specification table: «IEC 60705 RATING STANDARD».

The other figure, the one on the electricity bill, is the power it takes from the socket, and none of the 62 listings in the census publishes it. Two of the seven maker spec sheets we read for this guide do, and the gap between the two figures is plain to see. It is also why more watts do not mean more electricity per plate: the bill is watts multiplied by time, and the stronger one heats the same mug of milk in fewer minutes.

A microwave without a turntable takes rectangular dishes and one with a turntable does not. The reason is geometry: the dish turns with the plate, so its longest side has to fit inside a circle. The figure that decides it is published by two listings out of 62 in the census.

The two models from the same brand in this guide show it on their own. The one with a turntable stops at a 24.5 cm diameter; the one without offers a flat base of 29.7 by 29.6 cm, with the same 20 litres and a nearly identical box outside. On the second one's spec sheet the turntable diameter field reads zero, and that zero is the information.

A microwave has no energy label because the rule that creates the label leaves it out in writing. In Great Britain the energy labelling of domestic ovens is still Commission Delegated Regulation (EU) No 65/2014, kept as UK law, and its article 1(2)(b) says it does not apply to «ovens which offer a ‹microwave heating› function». There is no A class, no A+ and no kilowatt hours a year to compare, and that holds for a combination model and for a basic solo alike.

That is why the gap in consumption information has to be filled by the maker's spec sheet, and why it matters which of the two figures it publishes. The three we did find across the seven spec sheets of this guide are LG's, Balay's connection power and Corberó's standby.

A microwave works as an air fryer only if it has convection, and convection is declared with watts and degrees. Of the 62 listings in the census, eight use the words air fryer, six also name convection or hot air and two publish the watts of that function. Without that figure there is no way to know how much heat it moves, and a grill with a new name does not brown in the same way.

The difference shows in the kitchen, not on the spec sheet: a grill is an element at the top that heats the upper face by radiation; convection is a fan that moves hot air around the whole piece of food, which is exactly what an air fryer does. That is what separates a combination microwave from one with a grill. If that function matters to you, look at the watts before the name: the two listings that publish them give 2,200 W of hot air on one and a 1,300 W grill plus convection on the other. The checker in the calculator above has three fields for the one you are looking at.

The grill has its own gap. Thirty-seven of the 62 listings carry a grill and 21 publish its watts, so four in ten grill microwaves sell a heating element without saying how strong it is. And on the official page of one model in this guide, the specification table gives a 1,000 W grill while the highlights block of the same page gives 800 W, the figure the shop listing copies. When that happens, the specification table is the one to compare with, because it is the one the maker fills in the same way for every model.

A built-in microwave has two sizes and the one that matters is the second. The appliance size is the box with its frame; the housing size is the opening you have to leave in the cabinet. On the built-in model in this guide they are 382 by 595 by 335 mm for the appliance and a housing of 362 to 365 mm high, 560 to 568 wide and 320 deep, with the range included because wood moves.

It is the one decision in this category where a mistake costs the cabinet as well as the appliance. A countertop microwave pushed into a made-to-measure space is not a built-in: it lacks the air outlet the cabinet does not have and the frame that covers the gap.

A microwave draws more than most things on a kitchen worktop, and LG's UK manual says so plainly in its installation steps: «Make sure the microwave oven is the only appliance connected to the socket». At 1,150 W for the microwave and 1,450 W with the grill on the LG, that rules out sharing a four-way extension lead with the kettle.

The plug is a rule too. Regulation 12 of the Plugs and Sockets etc. (Safety) Regulations 1994 says an appliance can only be supplied in the UK fitted with a standard BS 1363 plug and a BS 1362 fuse, or with a conversion plug that encloses the foreign plug and can only be removed with a tool. A marketplace listing that says EU plug is the continental version, and a loose travel adaptor is not the same thing. And if it arrives faulty, section 22 of the Consumer Rights Act 2015 gives you 30 days, from the day after delivery, to reject it and ask for your money back instead of a repair.