Korea charges electricity in tiers, and the tiers bite
Most countries bill households at a flat rate per kilowatt-hour, or something close to it. Korea does not. Residential electricity is priced progressively across three tiers, and both the per-kWh rate and the fixed base charge climb as you move up. That structure is deliberate — it exists to discourage heavy consumption — and it's why the same apartment can produce a comfortable bill in May and an alarming one in August.
The most common misreading is assuming the top rate applies to everything you used. It doesn't. Each tier is charged only on the units falling within it. Use 350 kWh outside summer and the first 200 are billed at the tier 1 rate, with only the remaining 150 at the tier 2 rate. The base charge is the exception: the amount for your highest reached tier is applied once, in full.
The 400 kWh cliff
Outside July and August, the jump from 400 to 401 kWh is unusually expensive. The base charge rises from 1,600 to 7,300 won and the top per-kWh rate begins applying, so that single extra kilowatt-hour costs roughly 6,800 won rather than the few hundred you'd expect.
This is worth knowing near the end of a billing period. If you're at 390 kWh with a week to go, modest restraint is worth far more than usual. If you're already well into tier 3, the cliff is behind you and savings simply scale with the rate — still worthwhile, but without the step change.
Summer tiers are wider, not cheaper
From 1 July to 31 August the tier boundaries move outward: tier 1 extends from 200 to 300 kWh and tier 2 from 400 to 450 kWh. The rates themselves don't change — you simply stay in the lower brackets longer.
The effect is substantial. At 450 kWh you'd normally be in tier 3 paying the 7,300 won base charge, but in summer you remain in tier 2 at 1,600 won, and more of your usage is billed at the middle rate. The same consumption can differ by more than 20,000 won depending on the month.
What makes up the bill
The charged amount is not just energy. It's the base charge + energy charge + climate/environment charge + fuel cost adjustment, and then 10% VAT and a 2.7% electricity industry fund are added on top. The fund rate has been 2.7% since 1 July 2025 (3.2% the year before, 3.7% earlier). The climate and fuel components are per-kWh, so they scale with usage.
A few things this calculator can't know. Meter reading dates rarely align with calendar months, welfare discounts apply to some households, and the fuel cost adjustment is revised quarterly. More importantly, these are low-voltage rates — most Korean apartments are billed at high-voltage rates, which are lower, with shared building electricity appearing separately in the monthly maintenance fee. Detached houses and many officetels are on low voltage.
Rates used here
- Residential low voltage · base charge 910 / 1,600 / 7,300 won by tier
- Energy charge 120.0 / 214.6 / 307.3 won per kWh by tier
- Tier boundaries: 200 / 400 kWh standard · 300 / 450 kWh in July–August
- Climate charge 9.0 won/kWh · fuel cost adjustment 5.0 won/kWh
- VAT 10% · electricity industry fund 2.7% (Enforcement Decree of the Electric Utility Act, Art. 36, effective 1 July 2025)
Rates change and the fuel adjustment is revised quarterly. Check your KEPCO bill or the KEPCO ON service for exact figures.
Frequently asked questions
Why is my Korean electricity bill so high in summer?
Korea prices residential electricity progressively: the more you use, the higher the rate on the extra units, and the fixed base charge jumps between tiers too. Air conditioning pushes many households from tier 2 into tier 3, where both the base charge and the per-kWh rate rise sharply. The government widens the tiers in July and August to soften this, but heavy cooling can still cross into the top tier.
Does the highest rate apply to my whole usage?
No, and this is the most common misunderstanding. Each tier is charged at its own rate for only the units that fall inside it. If you use 350 kWh outside summer, the first 200 kWh are billed at the tier 1 rate and only the remaining 150 kWh at the tier 2 rate. The base charge is the exception — the full amount for your highest reached tier is applied once.
What happens at 400 kWh?
Outside summer, crossing from 400 to 401 kWh moves you into tier 3. The base charge jumps from 1,600 to 7,300 won and the top per-kWh rate kicks in, so a single extra kilowatt-hour can add roughly 6,800 won to the bill. If you are near a threshold late in the billing month, small savings are worth far more than usual.
I don't know my kWh — can I still use this?
Yes. Switch to the bill mode and enter the amount you were charged last month. The calculator searches backwards to find the usage that produces that bill, then projects next month based on how much your consumption is likely to change.
Will this match my actual bill exactly?
It's an estimate. Real bills reflect your meter reading dates, any welfare discounts, and a fuel cost adjustment that changes quarterly. This calculator uses low-voltage residential rates — most apartments in Korea are billed at high-voltage rates, which are cheaper, and apartment maintenance fees usually add a separate shared-electricity charge.