The Microwave Calculator
Microwave cooking instructions on food packaging often don't match your microwave's power settings, making it hard to know how long to cook your food. This microwave power and cooking time converter helps you adjust cooking times accurately based on your microwave's wattage.
Whether you're using a 700W, 800W, 900W, or 1000W microwave, or a microwave that lets you select a percentage power level, this tool gives you precise cooking times without the guesswork.
It's designed to be fast, mobile-friendly, and easy to use — perfect for quick access in the kitchen. It even has a timer function.
If you want better microwave cooking results, avoid undercooked meals, and save time, this microwave calculator is for you.
Generally it is better to microwave at a lower power and for longer - try that in the calculator!
How to Use It
- Set Packaging Instructions: Use the +/− buttons to match the power and time shown on your food packaging.
- Set Your Microwave Power: Choose either Power Mode (direct power setting) or Percentage Mode (microwave power and percentage). Adjust to match your microwave's settings.
- View Adjusted Time: The timer automatically calculates the correct cooking time to use for your microwave.
- Start Timer: If you want to use the timer here press "Start" to begin the countdown. Use +30/−30 or Pause to adjust the time while running.
Caution: If the timer shows orange or red, you're cooking much faster than recommended. Always check food frequently to ensure even heating.
Your microwave settings are saved automatically for next time.
Understanding Microwave Power
Microwaves vary in power from 300W to 1200W or more. On some models you can set the power directly, while on others the power is fixed and you adjust a percentage setting instead.
Understanding your microwave's power (or wattage) helps you adjust cooking times and choose the right power level for different tasks.
Microwave Wattage Guide
Many microwaves use direct power (wattage) settings (e.g., 600W, 700W, 900W). In most models the microwave is actually running at full power all the time, but cycling on and off to achieve the desired average power level. More expensive inverter microwaves use a different technology to provide more precise power control.
300-700W (Low Power): Compact and older microwaves. Best for reheating, defrosting, and gentle cooking. Expect longer cooking times but more even heating for delicate foods.
800-900W (Standard Power): The most common microwave power range found in homes. Good all-round performance for most cooking tasks with reasonable cooking times.
1000-1200W (High Power): Modern, powerful microwaves. Faster cooking times but requires more attention to prevent overcooking. Excellent for quickly heating large portions or boiling water.
Microwaves with direct power settings are typically easier to use, but always check your microwave's manual for specific instructions on using power settings.
Recommended Power Settings for Common Tasks
Boiling Water and Reheating Beverages: Use full power (whatever your microwave's maximum wattage is). Quick tasks benefit from maximum heat.
Reheating Cooked Foods and Cooking Fish: For an 800W microwave, use 600W. For 1000W, use 700-800W. This prevents drying out food whilst providing good heat.
Cooking Meats and Baking Cakes: For an 800W microwave, use 400-500W. For 1000W, use 500-600W. Lower power cooks food more evenly throughout.
Defrosting and Melting: For an 800W microwave, use 250-300W. For 1000W, use 300-400W. Low power prevents edges from cooking whilst the centre thaws.
Keeping Warm and Softening: Use 100-200W. Very gentle heating prevents cooking.
Simmering and Slow Cooking: For an 800W microwave, use 400W. For 1000W, use 500W. Allows dishes like casseroles, curries, and stews to cook gently, developing flavours without boiling over or drying out.
Recommended Percentage Settings for Common Tasks
Boiling Water and Reheating Beverages: Use 100% power. Maximum heat for quick results.
Reheating Cooked Foods and Cooking Fish: Use 70-80% power. This prevents food from drying out whilst ensuring thorough heating. For delicate fish, stay closer to 70%.
Cooking Meats and Baking Cakes: Use 50-60% power. The lower setting allows heat to penetrate evenly, preventing tough or unevenly cooked results. For dense meats like roasts, use 50%; for lighter items like cakes, 60% works well.
Defrosting and Melting: Use 30-40% power. This gentle approach prevents edges from cooking whilst the centre defrosts. For chocolate or butter, 30% is ideal. For frozen meats, 40% speeds the process whilst maintaining control.
Keeping Warm and Softening: Use 10-20% power. Very gentle heating that softens butter or cream cheese without melting, and keeps food warm without continuing to cook it. Also suitable for proving bread dough.
Simmering and Slow Cooking: Use 40-50% power. Allows dishes like casseroles, curries, and stews to cook gently, developing flavours without boiling over or drying out.