Microwave wattage converter: watts and time

Change the time in inverse proportion to the wattage: time on the pack × wattage on the pack ÷ your microwave’s wattage. 3 minutes at 800 watts becomes 4 minutes at 600 watts.

In your microwave

Example: 3 minutes at 800 watts on the pack, your microwave has 600 watts.

4 min instead of 3 min at 800 watts. Stir halfway through. At least 70 °C all the way through.

Your details

The converter asks for:

Wattage on the pack (600 to 1,000 watts)
Time on the pack (minutes and seconds)
Your microwave’s wattage

The calculation runs in your browser. Nothing is saved.

Conversion chart: 600 to 1,000 watts

Pack says 800 W: time in your microwave
800 W (pack)	600 W	700 W	900 W	1,000 W
2 min	2 min 40 sec	2 min 20 sec	1 min 50 sec	1 min 40 sec
3 min	4 min	3 min 30 sec	2 min 40 sec	2 min 30 sec
4 min	5 min 20 sec	4 min 40 sec	3 min 40 sec	3 min 20 sec
5 min	6 min 40 sec	5 min 50 sec	4 min 30 sec	4 min
6 min	8 min	7 min	5 min 20 sec	4 min 50 sec
8 min	10 min 40 sec	9 min 10 sec	7 min 10 sec	6 min 30 sec
10 min	13 min 20 sec	11 min 30 sec	9 min	8 min

Pack says 600 W: time in your microwave
600 W (pack)	700 W	800 W	900 W	1,000 W
2 min	1 min 50 sec	1 min 30 sec	1 min 20 sec	1 min 20 sec
3 min	2 min 40 sec	2 min 20 sec	2 min	1 min 50 sec
4 min	3 min 30 sec	3 min	2 min 40 sec	2 min 30 sec
5 min	4 min 20 sec	3 min 50 sec	3 min 20 sec	3 min
6 min	5 min 10 sec	4 min 30 sec	4 min	3 min 40 sec
8 min	7 min	6 min	5 min 20 sec	4 min 50 sec
10 min	8 min 40 sec	7 min 30 sec	6 min 40 sec	6 min

How the converter works

A microwave puts out a fixed amount of energy every second. For the same heat in your food, power × time stays the same: half the power, twice the time.
New time = time on the pack × wattage on the pack ÷ your microwave’s wattage. The converter rounds up to the next 10 seconds.
It’s an estimate: the amount, the starting temperature (from the fridge or frozen) and the container change the time. So always check that the food is hot all the way through.

Example: The pack says 10 minutes at 800 watts, your microwave has 600 watts.

10 minutes × 800 ÷ 600 = 13.3 minutes.
Rounded up: 13 min 20 sec

How to get it hot all the way through

Cover it, for example with a plate, and stir or turn it halfway through.
Reheated food must be piping hot all the way through, at least 70 °C – especially meat, poultry and rice.
Use glass or ceramic for heating, not plastic.
Let it stand for a moment afterwards so the heat spreads.

Frequently asked questions

How do I convert 800 watts to 600 watts?

Multiply the time by 800 and divide by 600: it takes about a third longer. 3 minutes at 800 watts becomes 4 minutes at 600 watts.

How long at 600 watts instead of 1,000 watts?

A good one and a half times as long. 2 minutes at 1,000 watts becomes 3 minutes 20 seconds at 600 watts.

My microwave has more watts than the pack. What now?

Then the food heats up faster: shorten the time as the converter shows. Or set your microwave to the wattage on the pack and use the time on the pack.

Where do I find the wattage of my microwave?

On the rating plate on the appliance or in the manual. You need the microwave output (for example 800 W), not the higher power it draws from the socket.

Why should I stir halfway through?

Microwaves heat unevenly. Stirring spreads the heat so the food reaches at least 70 °C everywhere.

Is food from the microwave unhealthy?

No. According to the German Federal Office for Radiation Protection (BfS), the changes in nutrients are similar to heating on the hob. What matters is the container and that the food gets hot all the way through.

Sources

Using the microwave properly: which foods you can reheat (in German). Consumer Advice Centre North Rhine-Westphalia (Verbraucherzentrale NRW), 2025
Microwave ovens (in German). Federal Office for Radiation Protection (BfS), 2023

Updated 19 October 2026