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Microwave Wattage Conversion Calculator
Food packages are tested in one microwave, often 1,100 watts. Enter the package wattage and time, then your microwave's wattage, and get the adjusted cooking time, plus times at every common wattage and power level.
Last updated:
Package instructions
W
Often 1,100 W or 1,000 W in the US.
min
sec
Your microwave
W
On the label inside the door, on the back, or in the manual.
Enter your values to see the result.
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How to use the Microwave Wattage Conversion Calculator
Enter the package wattage and time, and its power level if the package says something other than HIGH.
Enter your microwave's wattage, found on a label inside the door or on the back.
Choose the power level you plan to use.
Press Convert time to get the cooking time for your microwave.
Check the food early and let it stand for a minute so heat evens out.
The microwave wattage formula
A microwave's wattage is the rate it delivers energy to food. To heat the same food by the same amount you need about the same total energy, so time and power trade off directly:
Your time = package time × package watts ÷ your watts
If you use a lower power level, multiply your wattage by that percentage first: 70% power on a 1,000 W microwave behaves like a 700 W oven. Example: 4:00 at 1,100 W in a 900 W microwave is 240 × 1,100 ÷ 900 = 293 seconds, about 4:55.
Microwave time conversion chart
Times for food that takes the listed time in a 1,100 W microwave, rounded to the nearest 5 seconds.
1,100 W
1,000 W
900 W
800 W
700 W
0:30
0:35
0:35
0:40
0:45
1:00
1:05
1:15
1:25
1:35
2:00
2:10
2:25
2:45
3:10
3:00
3:20
3:40
4:10
4:45
4:00
4:25
4:55
5:30
6:15
5:00
5:30
6:05
6:50
7:50
Tips for even microwave cooking
Stir, rotate or flip halfway through, even with a turntable; microwaves heat in hot and cold spots.
Let food stand 1–2 minutes after cooking. Heat keeps spreading to the center.
Cover loosely with a microwave-safe lid or vented wrap to trap steam and heat more evenly.
Arrange thicker parts outward. The edges of a dish heat fastest, so put thin pieces in the middle.
Use a thermometer for leftovers and ready meals: 165°F (74°C) in the center is the safe reheating temperature.
Frequently asked questions
How do I convert microwave cooking time for different wattages?
Multiply the package time by the package wattage and divide by your microwave's wattage. For example, 3 minutes 30 seconds (210 seconds) at 1,100 W in a 700 W microwave is 210 × 1,100 ÷ 700 = 330 seconds, or 5 minutes 30 seconds.
How long do I microwave something in a 700 watt microwave?
About 1.57 times as long as the 1,100 W time on a package, or about 1.43 times as long as a 1,000 W time. A 2-minute 1,100 W instruction becomes about 3 minutes 10 seconds.
How do I find out my microwave's wattage?
Look for a label inside the door frame, on the back or underside of the oven, or in the owner's manual. It usually lists output power in watts, which is the number to use. The input power, which is higher, is not the cooking power.
What does a power level do in a microwave?
Lower power levels cycle the magnetron on and off, so 50% power on a 1,000 W microwave delivers about 500 W on average. That is why the calculator multiplies the wattage by the power level.
Why is the converted time only a starting point?
Microwave heating also depends on the food's starting temperature, its amount, shape and container, and how evenly your oven heats. Check the food a little early, stir or rotate it, and let it stand so the heat spreads. Ready meals and leftovers should reach 165°F (74°C).
Is a higher wattage microwave faster?
Yes. Cooking time is roughly inversely proportional to output power, so a 1,200 W microwave cooks in about 58% of the time a 700 W one needs for the same food.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.