How to Calculate Electricity Cost (kWh x Unit Price)
Electricity cost = kWh x unit price, where kWh = watts x hours / 1000. At a 31 JPY/kWh rate, a 1500 W microwave run 3 min uses 1500 x 0.05 / 1000 = 0.075 kWh, costing about 2.3 JPY.
Open the interactive Everyday Lifestyle tool →Energy formula: kWh = W x h / 1000
Key facts
| Energy formula | kWh = W x h / 1000 |
|---|---|
| Cost formula | cost = kWh x unit price |
| Reference unit price | 31 JPY/kWh |
| AC cooling 0.6 kW for 8 h | 0.6 x 31 x 8 = 148.8 JPY |
| 1 kWh CO2 (JP avg) | ~0.4 kg |
Frequently asked questions
How much does a 1200 W hair dryer cost for 10 minutes?
About 6.2 JPY: 1.2 kW x (10/60) h = 0.2 kWh, x 31 JPY/kWh = 6.2 JPY.
What is the unit price per kWh in Japan?
This tool uses 31 JPY/kWh as a reference; real bills add a base charge plus tiered rates (about 30 JPY/kWh for the first tier).
How do I convert watts to kWh?
kWh = watts x hours / 1000. A 1000 W appliance for 1 hour = 1 kWh.
Related pages
Electricity Cost Calculator is part of Everyday Lifestyle on GOAT Lab — a free reference you can use without signing up, and it works offline. Open the tool above for any custom value.
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