A household microwave generally draws between 1,000 and 1,500 watts while running, even if the box says 700 or 800 W. A real example: the Sharp R200WW, a 20-litre model, has 800 W of microwave power and an input power of 1,270 W, according to its spec sheet published by the retailer PcComponentes.
Used 15 minutes a day, a microwave like that uses about 9.5 kWh a month. With residential electricity at 255.27 pesos per kWh (CGE's price in cities such as Rancagua or Concepción since October 2026), that comes to about 2,430 pesos a month. Here is the calculation, how much a microwave uses per minute, how much it draws when off and when it beats the oven or the kettle.
How many watts does a microwave use
The most common confusion is between two power ratings. The one advertised (700, 800 or 1,000 W) is the output power: the energy that reaches the food as microwaves. The one you pay for is the input power, which is always higher, because the magnetron, fan, light and turntable also use electricity.
| Concept | What it means | Typical value |
|---|---|---|
| Output power (microwave) | Energy that heats the food | 700 to 1,000 W |
| Input power | What it draws from the grid while heating | 1,000 to 1,500 W |
| Grill power (if any) | Element for browning | 800 to 1,200 W |
| Standby consumption | Clock and display on | 1 to 4 W |
For the Sharp R200WW, the ratio between output and input is 800 / 1,270, or about 63%. The rest of the energy is lost as heat in the appliance itself. So to calculate your cost, look on the rear rating plate or in the manual for the input figure, often labelled “rated power” or “consumption”.
Estimated input power by advertised power
If your microwave does not show its input power, you can estimate it using the same ratio as in the example: divide the advertised power by 0.63. This is an Energía Futura approximation; the exact figure is on the appliance's rating plate.
| Advertised power (output) | Estimated input power | Consumption per minute | Cost per minute |
|---|---|---|---|
| 700 W | ~1,110 W | 18.5 Wh | ~4.7 pesos |
| 800 W | ~1,270 W | 21.2 Wh | ~5.4 pesos |
| 900 W | ~1,430 W | 23.8 Wh | ~6.1 pesos |
| 1,000 W | ~1,590 W | 26.5 Wh | ~6.8 pesos |
A more powerful microwave uses more per minute but also heats faster. In practice, for the same food, the total energy of a 700 W and a 1,000 W model is similar: the more powerful one finishes sooner.
How much a microwave uses per minute
With an input power of 1,270 W, a microwave uses 21.2 Wh per minute (1,270 ÷ 60). Each minute of use costs about 5.4 pesos at 255.27 pesos per kWh. These are typical uses:
| Use | Time | Consumption (at 1,270 W) | Approximate cost |
|---|---|---|---|
| Heat a cup of coffee or milk | 1.5 min | 0.032 kWh | ~8 pesos |
| Heat a plate of food | 3 min | 0.064 kWh | ~16 pesos |
| Defrost 500 g of meat | 8 min (medium power) | ~0.11 kWh | ~28 pesos |
| Make popcorn | 3.5 min | 0.074 kWh | ~19 pesos |
| Steam vegetables | 6 min | 0.127 kWh | ~32 pesos |
At medium or low power (defrost), a microwave does not reduce power continuously: it switches the magnetron on and off in cycles. So real consumption is roughly proportional to the power percentage chosen, plus the fixed draw of the fan and light.
How much a microwave costs per month
Monthly consumption depends mainly on how many minutes a day you use it. Most homes use it between 5 and 20 minutes a day. With an appliance drawing 1,270 W and electricity at 255.27 pesos per kWh:
| Daily use | kWh per month | Cost per month | Cost per year |
|---|---|---|---|
| 5 minutes | 3.2 kWh | ~810 pesos | ~9,700 pesos |
| 10 minutes | 6.4 kWh | ~1,620 pesos | ~19,500 pesos |
| 15 minutes | 9.5 kWh | ~2,430 pesos | ~29,200 pesos |
| 20 minutes | 12.7 kWh | ~3,240 pesos | ~38,900 pesos |
| 30 minutes | 19.1 kWh | ~4,860 pesos | ~58,300 pesos |
For perspective: an average home in Chile uses about 180 kWh a month, according to the National Energy Commission. With normal use, the microwave accounts for 2% to 7% of the bill. The refrigerator, which runs 24 hours a day, weighs much more, as we explain in how much electricity a refrigerator uses.
The price per kWh varies by city and utility: in CGE areas it ranges from 240.83 to 285.56 pesos. You can find yours in the price per kWh by city and utility and adjust the calculation by multiplying your kWh by that value.
How much electricity a microwave uses when off (standby)
A microwave spends more than 99% of the time not heating, but with the clock on. In the United States, the Department of Energy (DOE) set in 2013 a 1 watt standby limit for microwaves made from June 17, 2016, according to the rule published in the Federal Register. Before that rule, the ASAP group found models drawing about 4 W on standby, some 35 kWh a year, and estimated that a typical microwave heats food only about 70 hours a year.
| Standby consumption | kWh per month | Cost per month | Cost per year |
|---|---|---|---|
| 1 W (efficient modern unit) | 0.72 kWh | ~184 pesos | ~2,200 pesos |
| 2 W | 1.44 kWh | ~368 pesos | ~4,400 pesos |
| 4 W (older unit) | 2.88 kWh | ~735 pesos | ~8,800 pesos |
In an older microwave, standby can cost almost as much as using it five minutes a day. Unplugging it, or connecting it to a power strip with a switch, removes that cost, though you will have to reset the clock.
Microwave, electric oven or kettle: which uses less
For small portions, the microwave almost always wins. A 2,000 W electric oven needs about 10 minutes to preheat and heats all the air and walls, not just the food. The microwave heats the water in the food directly. These are comparisons calculated by Energía Futura with typical power ratings:
| Task | With a microwave (1,270 W) | With the alternative | Difference |
|---|---|---|---|
| Reheat a plate | 3 min: 0.064 kWh (~16 pesos) | 2,000 W oven, 10 min preheat + 10 min: 0.67 kWh (~170 pesos) | The microwave uses 10 times less |
| Heat 250 ml of water | 2 min: 0.042 kWh (~11 pesos) | 2,000 W kettle, ~1 min: 0.035 kWh (~9 pesos) | The kettle wins narrowly |
| Heat 1 litre of water | ~8 min: 0.17 kWh (~43 pesos) | 2,000 W kettle, ~3.5 min: 0.12 kWh (~30 pesos) | The kettle wins |
| Roast a whole chicken | Not recommended | Electric oven, 60 min: ~1.5 kWh (~383 pesos) | The oven is needed |
The practical conclusion: for reheating and defrosting, the microwave is the most efficient appliance in the kitchen. For boiling water, the electric kettle is faster and uses slightly less. The oven is for what only it does well: roasting and baking. These times are approximate and depend on each appliance's power and the amount of food.
How to spend less with your microwave
- Cover the food: it keeps the steam in, heats more evenly and faster.
- Use wide, shallow dishes: food in a thin layer heats faster than in a deep bowl.
- Thaw in the fridge when you can: planning ahead saves several minutes of microwave time.
- Do not use it to boil a lot of water: for more than a cup, the kettle is more efficient.
- Clean the inside: food residue also absorbs energy.
- Unplug it if it is old: standby in an older unit can cost up to about 8,800 pesos a year.
If you want to know how much all your appliances weigh together, see how much electricity a house in Chile uses per month, with a breakdown by appliance and how to read it on your bill.
Do you sell energy-efficient appliances? Reach Energía Futura readers who compare consumption before buying.
See advertising optionsFrequently asked questions
How many watts does a microwave use?
Between 1,000 and 1,500 watts while heating. The 700 to 1,000 W advertised is the output power, not the consumption.
How much does a microwave cost per month?
With 15 minutes of daily use, about 9.5 kWh a month, around 2,430 pesos at 255.27 pesos per kWh.
Does a microwave use a lot of electricity?
Not over a month. Although its power is high, it is used only a few minutes a day. It usually accounts for 2% to 7% of an average home's bill.
Should I unplug the microwave?
For older units, yes: they can draw about 4 W on standby, around 735 pesos a month. Recent models meeting the 1 W standard spend about 184 pesos a month on standby.
How much does a microwave with grill use?
The grill element adds 800 to 1,200 W. Using microwave and grill together, consumption can exceed 2,000 W.
