Most guides about saving on electricity in Japan focus on usage: turn off the aircon, unplug things, switch time-of-use plans. But there is a much simpler lever that almost no foreign resident is told about, because it is buried in Japanese-language account settings and nobody explains it in English: your amp contract, or アンペア (anpea).
In most of Japan, your monthly bill has two parts — a fixed 基本料金 (kihon ryōkin, "base charge") that you pay every month no matter how much electricity you use, and a usage charge based on kWh consumed. In amp-based regions, that base charge is set by the amperage of your contract: 20A, 30A, 40A, 50A, 60A, and so on. A 50A contract carries a noticeably higher fixed charge than a 20A contract — every single month, even in a month where you barely turn anything on. If your apartment was set up on a higher amperage than your household actually needs, you are quietly overpaying for capacity you never use.
Why apartments often end up over-amped
When a rental unit is first wired or a new tenant moves in, the amperage is often left at whatever the previous resident had, or set generously "just in case" by a landlord or agent who isn't paying the bill. A family of four running a washer-dryer, IH stove, and multiple air conditioners at once genuinely needs more amperage than someone living alone with a compact kitchen. But many single residents and couples are sitting on a 40A or 50A contract when 20A or 30A would comfortably cover their actual daily use.
How to check your current amperage
You do not need to guess. There are two easy ways to find your current contract amperage:
- Your 検針票 (kenshinhyō) — the meter reading slip or usage notice your provider sends monthly (by paper or app). The contracted amperage is usually printed near your customer number and plan name.
- Your breaker box — the main ブレーカー (burēkā, breaker) at the entrance of your breaker panel is often color-coded and labeled with a number (e.g. "30A"). This is the amp limit for your whole home.
Estimating what you actually need
A rough way to think about it: add up the appliances you might realistically run at the same time — for example, air conditioner, refrigerator, microwave, and lighting on a normal evening. If you rarely stack more than two or three power-hungry appliances simultaneously, you likely have room to drop a tier. As a general pattern:
- Living alone or with light simultaneous appliance use: 20A–30A is often enough.
- A couple or small household with normal cooking and aircon use: 30A–40A is typical.
- Larger households running several appliances together (IH stove, dryer, multiple aircon units): 40A or higher may genuinely be needed.
Exact base charge amounts differ by provider and region, so rather than quoting fixed yen figures here, use the calculator to compare your current amperage against a lower tier and see the estimated monthly difference for your own numbers.
The honest trade-off
Lowering your amperage is not free money with no downside. The whole point of the amp limit is that it caps how much electricity your home can draw at once. If your total simultaneous load goes over your contracted amperage, the main breaker trips and your power cuts out — for example, running the air conditioner, a microwave, a hair dryer, and an IH stove burner all at the same moment on a 20A contract is a classic way to trip the breaker. This is not dangerous and is fixed instantly by flipping the breaker back on, but it is an inconvenience, especially if it happens mid-shower or mid-cooking.
In short: a lower amp contract suits people who don't often run several high-draw appliances at the exact same time. If you already know your household regularly maxes out several appliances together, downgrading may cause more breaker trips than it's worth.
How to actually change it: Contact your electricity provider (this can usually be done by phone or through their online account portal) and request a change in contracted amperage. The change itself is free. In many cases the grid operator needs to physically adjust the breaker or meter, which may involve a short technician visit — but this does not require a real power outage for your household, and there is no fee for the change itself.
Where this does not apply
This entire lever only exists in amp-based regions. If you live in the Kansai, Chugoku, Shikoku, or Okinawa electricity areas, your provider uses a minimum-charge system instead — there is no amperage tier to choose, and the base charge is not tied to an amp contract at all. If you're in one of these regions, amp downgrading simply does not apply to your bill, and you should look at other savings levers instead.
To see whether you're in an amp-based region and how much a lower amperage tier could realistically save on your specific bill, run your numbers through the electricity cost calculator, which lets you compare different amperage contracts side by side. For more background on how the base charge and usage charge fit together, see how your Japan electricity bill is structured. If you're setting up service for the first time, our guide on electricity setup when moving to Japan covers what to check before you sign a contract. And if you have more general questions about billing, plans, or providers, check the FAQ.
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