Microwaves are among the cheapest kitchen appliances to run because they only draw power while actively cooking – unlike an oven that needs long preheat and hold times. Our free Microwave Oven Running Cost Calculator below shows you the daily, monthly and yearly running cost based on your microwave’s wattage and how many minutes a day you actually use it.
Microwave Oven Running Cost Calculator
Microwave Oven Running Cost Calculator
Use the “Power Input” or “Rated Input Power” on the rating label, not the cooking wattage on the front (e.g. “1000W cooking power” often draws 1500-1700W input). Compact microwaves: 900-1200W input, standard: 1200-1700W, large/commercial: 1700-2500W.
Add up all the minutes it actively runs across the day (reheating, cooking, defrosting) – not the time it’s just plugged in.
Auto-filled with a typical average – edit to match your own bill.
How Much Does It Cost to Run a Microwave?
A microwave's running cost is simple to calculate because it only draws its rated power while actively heating - there's no duty cycle or standby cycling to account for like a fridge or AC. The formula is:
Cost = (Wattage / 1000) x (Minutes Used Per Day / 60) x Electricity Rate per kWh
One common mix-up: the wattage printed on the front of a microwave (e.g. "900W") is the cooking power delivered to the food, not the actual electricity drawn from the wall. Microwaves are only about 55-65% efficient at converting electrical power into microwave energy, so a "900W" microwave typically pulls 1300-1600W from the outlet while running. Always use the "Rated Input Power" from the rating label for an accurate cost estimate.
Microwave Running Cost by Size
| Microwave Type | Typical Input Wattage | Cost/Month (US, $0.17/kWh, 15 min/day) | Cost/Month (India, Rs 8/kWh, 15 min/day) |
|---|---|---|---|
| Compact (700-900W cooking) | ~1000W | $1.28 | Rs 60 |
| Standard (1000-1200W cooking) | ~1400W | $1.79 | Rs 84 |
| Convection / Large (1200-1500W) | ~1900W | $2.42 | Rs 114 |
3 Ways to Save on Microwave Running Cost
- Cover food while reheating - a lid or microwave-safe cover traps steam and heats food faster, cutting run-time by 20-30% versus an uncovered dish.
- Cut food into smaller/even pieces - evenly sized pieces heat through faster and more consistently, reducing the extra minutes spent re-zapping cold spots.
- Use the microwave instead of the oven for small jobs - a microwave uses a fraction of the energy an oven does for reheating or cooking small portions, since there's no long preheat cycle.
Frequently Asked Questions
How many watts does a microwave use?
The wattage on the front (e.g. 900W) is cooking power, not electrical draw. Actual input power (what you're billed for) is typically 1000-1700W depending on size, listed as "Rated Input Power" on the label.
How much does it cost to run a microwave per month?
For 15 minutes of daily use, a standard microwave (around 1400W input) costs roughly $1.79/month in the US at $0.17/kWh, or about Rs 84/month in India at Rs 8/kWh.
Is a microwave cheaper to run than an oven?
Yes, significantly. A microwave heats food directly without needing to warm the surrounding air or a large cavity, so it typically uses 50-70% less energy than an oven for the same reheating or small-cooking task.
Why is my microwave's wattage on the box different from what it draws?
The box/front-panel wattage is "cooking power" - the microwave energy actually delivered to the food. Because the magnetron and electronics aren't 100% efficient, the microwave pulls 40-60% more power from the wall than its cooking-power rating.
Does using the microwave a lot raise my electricity bill noticeably?
Not much - even heavy daily use (an hour total) typically adds only a few dollars a month, since it draws power only while actively running and most sessions are just a few minutes.
Does covering food save microwave running cost?
Yes. Covering food traps steam and heat, letting it reach temperature 20-30% faster, which directly reduces the minutes the magnetron needs to run.