Microwave wattage explained: how many watts do you need?
Wattage is the number on every microwave box, and it is the one most often misunderstood. More watts is not automatically better, and the headline figure tells only half the story. Here is what wattage actually means, how much you need, and why how the power is delivered matters more than the number itself.
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What microwave wattage actually means
Wattage measures how much cooking power a microwave can deliver. A higher-wattage model can put more energy into your food in the same time, so it heats faster. Most solo microwaves sold in the UK fall between 700 and 900 watts. That range matters because it determines not just speed but how reliably the timings on ready-meal packets and recipes work, since those instructions assume a particular power level. Get a model whose wattage is wildly different from what the packet expects and you will spend your life adding or subtracting time.
Why 800 W is the everyday sweet spot
For most people, 800 watts is the right amount of power. It is quick enough to reheat a plate of food or defrost meat at a sensible pace, and crucially it is the level most ready-meal instructions are written for, so packet timings simply work without adjustment. The everyday solos we recommend, including the Samsung MS23K3513 and the Russell Hobbs RHM2076, are 800 W for exactly this reason.
A 700 W model still works perfectly well, but it is slower, and you will often need to add time to packet instructions, which is a small daily annoyance. A 900 W or higher model speeds things up, which is handy if you are impatient or reheat a lot of large portions, but it is rarely the upgrade people imagine, and at very high power some foods can overcook at the edges before the centre catches up. For most kitchens, 800 W is the sensible default and chasing higher numbers brings little real benefit.
Power levels and inverters: why delivery beats headline watts
Here is the part the box does not tell you, and it matters more than the wattage figure. Reheating evenly is not about raw power but about how lower power settings are produced. A conventional microwave does not actually reduce its power; it switches full power on and off in bursts to average out a lower setting. That stop-start delivery is exactly why so many basic microwaves leave food hot at the edges and cold in the middle, and why delicate jobs like softening butter or melting chocolate so easily go wrong.
An inverter microwave, by contrast, delivers steady, genuinely lower power. There is no pulsing, so the heat spreads through the food evenly and gentle jobs stay gentle. The Panasonic NN-DF386 uses inverter technology, and it is the main reason it reheats more evenly than anything cheaper on our list. If even reheating matters to you, an inverter is worth far more than an extra hundred watts of headline power. Beyond that, a microwave with several usable power levels simply gives you finer control for different jobs.
Wattage is not the same as size
One last point that trips people up: wattage and capacity are completely separate. Watts measure cooking power; litres measure how big the cavity is. A small 17-litre microwave can be 800 W, and a large 28-litre one can be the same. So decide your power and your size independently, and do not assume a bigger microwave is more powerful or a more powerful one is bigger. Our buying guide covers how to choose capacity, and our small-kitchen guide helps if space is tight.
Frequently asked questions
How many watts is a good microwave?
For everyday use, 800 watts is the sensible level: quick enough to reheat and defrost without overcooking the edges. Models from 700 W work but are slower, while 900 W and above speed things up further. Wattage measures cooking power, which is separate from cavity size, measured in litres.
Is an 800 W microwave better than a 700 W one?
It is faster, and it follows packet instructions more reliably, since most ready-meal timings assume around 800 W. A 700 W model still works but you may need to add time. For most kitchens, 800 W hits the right balance of speed and gentle, even cooking.
What are microwave power levels for?
Power levels let you cook at less than full power, which matters for jobs like defrosting, softening butter or gently reheating delicate food. A conventional microwave creates lower power by pulsing full power on and off; an inverter delivers steady lower power, which heats more evenly. More usable power levels give you finer control.
Our advice in one paragraph
For most kitchens, buy an 800 W microwave: it is fast enough, and packet timings just work. Treat 700 W as a slower budget option and 900 W and above as a minor speed upgrade rather than a meaningful improvement. If even reheating matters, prioritise an inverter, such as the one in our best overall Panasonic NN-DF386, over chasing extra watts. And remember that wattage and capacity are separate decisions, so pick your power and your size on their own terms. Next, read our solo versus combination guide to settle the type.