How Many Watts Does a Microwave Use? Cooking Power vs Input Watts
By Seamless Home Team, Home services operations · October 1, 2026 · Updated October 1, 2026
Quick answer
A typical full-size countertop microwave delivers about 900 to 1,200 watts of cooking power to the food, and draws roughly 1,400 to 1,700 watts from the outlet while it runs — often around 10 to 13 amps at 120 volts. Compact models are lower; some over-the-range and convection models are higher. The cooking wattage is on the box and the front panel; the electrical input is on the rating label inside the door frame or on the back. Divide cooking power by 120 and you understate the current by about a third. Over a day a microwave still uses little energy, because it runs for minutes rather than hours: 1,500 W for 15 minutes is 0.375 kWh. At 16 cents per kWh that is about six cents a day, or roughly $1.80 a month if that is your usual use.
A microwave's wattage looks simple until you notice there are two of them. The number on the box — 900, 1,000, 1,200 watts — is cooking power, the microwave energy that reaches the food. The number that sets the bill, the breaker and the inverter is input power, and it is higher.
| Figure | Typical full-size countertop | Where to find it | What it is for |
|---|---|---|---|
| Cooking power | about 900–1,200 W | the box, the manual, the front panel | Comparing how fast ovens cook |
| Input power | often about 1,400–1,700 W | the rating label | Amps, circuits, inverters, energy cost |
| Rated current | roughly 10–13 A at 120 V | the rating label | Whether it fits the circuit |
The ranges are typical, not a specification. Compact models sit lower; some over-the-range and convection models sit higher. The label on your oven is the only figure that describes it.
Why cooking power understates the draw
Producing microwave energy is not efficient. The magnetron and the high-voltage supply that drives it lose a substantial share as heat, and the fan, cavity light, turntable and controls draw power too. So the oven takes considerably more from the outlet than it delivers to the food.
That is the same trap as reading a motor's shaft horsepower as electrical input — the reason the kW to watts calculator and the watts to kW calculator stay on real power, and why how many amps a microwave uses starts from the rating label rather than the box.
Reading the rating label
The input figure is on the rating label — usually on the door frame, inside the cavity edge, or on the back. It reads something like 120 V ~ 60 Hz, 1,500 W or 12.5 A.
If the label gives watts, divide by the voltage for a rough current:
- 1,500 W ÷ 120 V ≈ 12.5 A
- 1,200 W ÷ 120 V = 10 A
A microwave's power supply is not a pure resistive load, so volts × amps and watts are not exactly equal. If the label gives both, use the amps it states for circuit questions. What power factor is explains the gap, and the watts to amps calculator applies it.
Working backwards is a useful check. Divide cooking power by the label current and you get a "voltage" well under 120 — 1,000 W ÷ 12.5 A is 80 V — which is the sign that the two watt figures are not the same kind. The watts to volts calculator flags exactly that mismatch.
What it costs to run
Microwaves look powerful and use little energy, because they run for minutes. Energy is power × time:
| Input watts | Minutes a day | kWh a day | kWh a month | Cost/month at 16¢ | at 25¢ |
|---|---|---|---|---|---|
| 1,200 W | 10 | 0.20 | about 6 | about $1.00 | about $1.50 |
| 1,500 W | 15 | 0.375 | about 11 | about $1.80 | about $2.80 |
| 1,700 W | 20 | about 0.57 | about 17 | about $2.70 | about $4.20 |
The watts to kWh calculator turns any wattage and runtime into the same daily and monthly figures. Standby power for the clock and controls adds a small amount on top — usually well under 5 W on modern units.
Shared kitchen circuits
The wattage matters for the bill; the amps matter for the breaker. A kitchen's countertop receptacles sit on 20-amp small-appliance branch circuits. A microwave at roughly 12 A and a toaster, kettle or coffee maker at 8 to 12 A on the same circuit will trip it. Use the two kitchen circuits, or give a fastened-in-place over-the-range unit the individual branch circuit its installation instructions usually require under NEC 110.3(B).
The amp side — including the 80 percent continuous-load limit for a single cord-and-plug appliance — is covered in how many amps a microwave uses.
Inverters and power stations
Size against input watts, not cooking power. A portable power station advertised for a "1,000 W microwave" still has to deliver the oven's 1,400–1,700 W input, plus headroom for the brief inrush when the magnetron starts. Continuous rating and surge rating are separate limits; the lower of the two that your oven needs is the one that fails first.
When a different appliance is the better comparison
A microwave's short, high draw is the opposite of a refrigerator, which averages far less than it draws while the compressor runs, and different again from an air fryer, whose watts are usually the real electrical input printed on the label. For whole-house context, see how many watts a house uses.
If you are planning home electrical or appliance work and want a licensed contractor to review the load path, request a homeowner estimate. Coverage is confirmed per service area rather than promised as blanket availability.
Frequently asked questions
How many watts does a microwave use?
More than the number on the box. A microwave sold as 1,000 or 1,100 watts of cooking power typically draws several hundred watts more from the outlet — an input of around 1,400 to 1,700 watts is common for a full-size countertop model. The rating label inside the door or on the back gives the input figure for your oven.
What is the difference between cooking watts and input watts?
Cooking watts are the microwave energy delivered to the food — the figure used to compare how fast ovens cook. Input watts are what the oven takes from the outlet, including magnetron and power-supply losses plus the fan, light, turntable and controls. Input is the figure for amps, circuits, inverters and energy cost.
How many watts is a 1,000 watt microwave?
1,000 watts of cooking power. The electrical input is higher — often roughly 1,400 to 1,600 watts on a full-size model. Read the rating label; do not treat the box number as outlet draw.
How much does it cost to run a microwave?
Very little in total, because runtime is short. At 1,500 watts input for 15 minutes a day you use about 0.375 kWh a day, or roughly 11 kWh a month. At 16 cents per kWh that is about $1.80 a month; at 25 cents about $2.80. Standby power for the clock and controls adds a small amount on top.
How many watts does a microwave use on standby?
A few watts for the clock, display and controls — typically well under 5 W on modern units, though older displays can be higher. Over a month that still adds only a kilowatt-hour or two. Unplugging or a switched outlet removes it if it matters.
Can I run a microwave on a power station or inverter?
Size against the input watts on the rating label, not the cooking power on the box. A supply matched to 1,000 W cooking power will be undersized for a 1,500 W input. Microwaves also draw a brief inrush when they start, so surge headroom matters as well as continuous rating.
How many amps is that?
Divide input watts by 120 for a rough amp figure at US household voltage — 1,500 W is about 12.5 A — or read the amps the label already states. How many amps a microwave uses covers the circuit rules that follow from that current.