Microwave Wattage Converter
Convert cooking time between any two microwave wattages — instantly, both ways.
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The formula
timeB = timeA × (wattageA ÷ wattageB)
Example: 3:00 at 1000 W becomes – on a 700 W microwave and – on a 1250 W microwave.
Quick conversion table
Equivalent times for recipes written at 1000 W.
| Your microwave | 1:00 | 2:00 | 3:00 | 5:00 |
|---|---|---|---|---|
| 600 W | 1:40 | 3:20 | 5:00 | 8:20 |
| 700 W | 1:26 | 2:51 | 4:17 | 7:09 |
| 800 W | 1:15 | 2:30 | 3:45 | 6:15 |
| 900 W | 1:07 | 2:13 | 3:20 | 5:33 |
| 1000 W (base) | 1:00 | 2:00 | 3:00 | 5:00 |
| 1100 W | 0:55 | 1:49 | 2:44 | 4:33 |
| 1250 W | 0:48 | 1:36 | 2:24 | 4:00 |
Honest limits
The linear formula is an approximation. It assumes every watt goes into heating the food equally, but real microwaves cycle power on and off, heat unevenly, and foods absorb energy at different rates. Always treat the converted time as a starting point — check the food, stir/rotate, and add time in short bursts. Do not rely on converted times for food safety decisions (use a food thermometer: 75 °C / 165 °F for reheated leftovers).
- Frozen or very dense foods do not scale linearly — the surface absorbs energy while the center stays cold. Converted times can undercook the middle.
- Defrosting is not linear at all; use your microwave's defrost mode instead of this converter.
- Power-level settings (50%, 70%…) cycle the magnetron on/off — this converter assumes 100% power.
- Small times (under ~30 s) are dominated by heat-up quirks; the formula is most reliable for 1–10 minutes.
FAQ
Is the microwave wattage conversion formula really linear?
The formula time_B = time_A x (wattage_A / wattage_B) is a linear approximation. In practice microwaves cycle power on and off and heat food unevenly, so treat the converted time as a starting point: check the food and adjust in short bursts.
Why is my food still cold in the middle after converting the time?
Frozen, thick, or very dense foods do not heat linearly - the surface absorbs energy while the center stays cold. Converted times can undercook the middle of dense items, so stir, rotate, or let the food rest, and add extra time if needed.
How do I find my microwave's wattage?
Check the label inside the door or on the back panel of the microwave. Typical compact models are 600-800 W, standard models 900-1100 W, and high-power models up to 1250 W.
Can I use this converter for defrosting?
No - defrosting is not linear at all. Use your microwave's defrost mode instead of this converter; it is designed for reheating and cook times from recipes written for a different wattage.
How should I enter the time?
Type minutes:seconds (for example 3:00) or switch to seconds mode and type plain seconds (for example 180). The result is shown both ways automatically.
Free tool by NRTechStudio