How the electricity bill climbs its steps — three tiers, and the wider tiers of summer

In one corner of your electricity bill, this month's usage is printed. Say it reads "300 kWh." That one number tells you almost everything about how your home's electricity charge was worked out.

A strange taxi meter

The key is a taxi meter. A slightly odd taxi meter, though. For the first 200 kWh it ticks slowly, for the next 200 kWh faster, and above that, fastest of all. This setup, where each unit costs more the more you use, is the Progressive tariff A progressive tariff charges a higher unit price for the extra electricity used as consumption rises. Glossary →. Once you know how this meter runs, you can work out your home's charge yourself from one line on the bill.

How many steps are there, and what does each unit cost?

Electricity coming into a home (residential low voltage: the rate for homes that take power at a low voltage, like the 220V at a wall socket) splits a month's use into three steps (a top step, added only in months of very heavy use, comes later). In months other than July–August, up to 200 kWh is the first step, up to 400 kWh the second step, and anything above that the third step.Source 1KEPCO (Korea Electric Power Corporation), *Residential (low voltage) tariff table* (「주택용 전력(저압) 요금표」, effective 9 Nov 2023, unofficial translation)See in sources →

Each step differs in two prices: the price charged per kWh (the energy charge rate) and the basic charge added once a month. All prices are in won, the Korean currency.

Step (outside July–August)	Basic charge (won/household)	Energy charge (won/kWh)
200 kWh or less	910	120.0
201–400 kWh	1,600	214.6
Over 400 kWh	7,300	307.3

When we opened the tariff table again on 2026-10-26, this was still the latest effective date.

Data KEPCO (Korea Electric Power Corporation), residential (low-voltage) tariff table (「주택용 전력(저압) 요금표」), effective 2023-11-09 (same rates since 2023-05-16)© Renuary

A unit on the third step costs about 2.6 times a unit on the first step.

Use 250 kWh — do all 250 kWh get pricier?

No. It's a common misunderstanding. Using 250 kWh does not put the second-step price on all 250 kWh.

First 200 kWh → 120.0 won each
The 50 kWh over → 214.6 won each

Climb a step, and the higher price applies only to the part that stands on that step. It is a staircase price, not an elevator price: an elevator charges the top-floor price for the whole ride once you step in, while stairs charge only for the steps you climb. The basic charge is different, though: you pay the whole basic charge of just one step, the last step you reached that month (more on this later).

Price steps up with use — summer widens the steps

Rates match the tariff table in the text (KEPCO supply terms, residential low voltage). Grey: usual steps; orange: July–August. The top step for very heavy months is left out.

What changes in summer?

In July–August, when the air conditioners go on, the steps get wider. The first step stretches up to 300 kWh and the second up to 450 kWh.Source 1KEPCO (Korea Electric Power Corporation), *Residential (low voltage) tariff table* (「주택용 전력(저압) 요금표」, effective 9 Nov 2023, unofficial translation)See in sources → The price per unit and the basic charge for each step stay the same; only the width of the steps grows (910 won basic charge up to 300 kWh, 1,600 won up to 450 kWh). It is a device to keep the same usage on a cheaper step, and since 2019 it has been a standing rule used every year.Source 2Ministry of Trade, Industry and Energy (산업통상자원부), press briefing (13 Dec 2016)· press release (1 Jul 2019)See in sources →

The staircase itself is lower than it used to be. Starting with usage in December 2016, six steps were cut to three, and the most expensive step's rate went from 11.7 times the cheapest step's to 3 times.Source 2Ministry of Trade, Industry and Energy (산업통상자원부), press briefing (13 Dec 2016)· press release (1 Jul 2019)See in sources → The 3 times is the figure from the 2016 overhaul. With today's tariff table, it is the roughly 2.6 times we saw above.

What does a 300 kWh home pay in April and in August?

Two bills from the same home sit side by side on the kitchen table. One is for April and one for August, and the usage line on both reads 300 kWh (an example). We count only the basic charge and the energy charge (leaving out the Climate and environment charge The climate and environment charge is the line on a Korean power bill that shows policy costs such as renewable deployment and emissions reduction. Glossary →, the Fuel Cost Adjustment Charge A bill item that passes changes in generation fuel prices through to electricity bills. Each month it adds usage multiplied by the fuel cost adjustment rate. Glossary →, value-added tax and the fund levy).

In April, 300 kWh falls on the second step.

Basic charge → 1,600 won
First 200 kWh × 120.0 won → 24,000 won
The 100 kWh over × 214.6 won → 21,460 won
Total → 47,060 won

In August, the same 300 kWh fits inside the widened first step.

Basic charge → 910 won
300 kWh × 120.0 won → 36,000 won
Total → 36,910 won

Same 300 kWh, yet August is more than 10,000 won cheaper. That is the effect of widening the steps in summer.

What if you use 100 kWh more in August?

What about an August of hot, sleepless nights, with the air conditioner on every night? A home whose usage line climbs to 400 kWh steps onto the second summer step.

Basic charge → 1,600 won
First 300 kWh × 120.0 won → 36,000 won
The 100 kWh over × 214.6 won → 21,460 won
Total → 59,060 won

That is more than 22,000 won above the 300 kWh bill. The same 100 kWh costs different amounts depending on which step that 100 kWh lands on. To work it out to the last digit with your own home's usage, use the electricity bill calculator.

Is there one more step at the top?

There is. In July–August and December–February, if a home uses more than 1,000 kWh in a month, only the part above 1,000 kWh is charged an energy charge of 736.2 won per kWh instead of the third-step price (307.3 won).Source 1KEPCO (Korea Electric Power Corporation), *Residential (low voltage) tariff table* (「주택용 전력(저압) 요금표」, effective 9 Nov 2023, unofficial translation)See in sources → The tariff table has no separate basic charge for this case. The basic charge column stops at the third step's 7,300 won, and this piece could not confirm whether 7,300 won is simply charged in such a month. This is the so-called super-user rate. It is more than twice the third-step price. It is a top step charged separately, only to homes that use a very large amount.

Put the energy charge for the same 100 kWh on each step side by side, and you can see the size of it.

First step → 12,000 won
Second step → 21,460 won
Third step → 30,730 won
Top step → 73,620 won

100 kWh on the top step costs more than 6 times 100 kWh on the first step. Run the same air conditioner for the same hours, and the price can differ this much depending on which step you were on that month.

Why bother with steps at all?

The government sets the standards for calculating electricity rates in a public notice. This notice says the rate structure should be based on the cost of supply, while sharing the burden evenly among users. It then states that, where needed for the efficient allocation of resources, rates can be supplemented with a rate that rises the more you use (a progressive rate) or differentiated rates.Source 3Notice on detailed generation licensing criteria, electricity tariff calculation criteria, meter tolerance and grid operation (「발전사업세부허가기준, 전기요금산정기준, 전력량계허용오차 및 전력계통운영업무에 관한 고시」, unofficial translation) Art. 14,전기요금산정기준,전력량계허용오차및전력계통운영업무에관한고시/제14조 See in sources → The progressive tariff stands on that one line.

The tariff table itself is drawn up by KEPCO, and it takes effect only after the minister's approval (the government's permission).

Do shops and factories have steps too?

No. Even in the same building, the bill for the shop on the ground floor has no steps. The progressive tariff exists only for homes. The general-service rate for shops and offices and the industrial rate for factories do not charge more per unit for using more.

Instead, some general-service and industrial users pay time-of-use rates, which split the day into off-peak, mid-peak and peak bands with a different price per unit for each.Source 4KEPCO, *Notice of amendments to the Basic Supply Terms (new optional rate for general service (A) II)* (「기본공급약관 개정사항 안내(일반용(갑)Ⅱ 선택요금 신설)」, notice, 26 May 2026, unofficial translation)weekday off-peak, mid-peak and peak time bands apply to general service (A) II and (B), industrial (A) II and education (B).See in sources → Retail rates whose price per unit changes by time of day are found here, not in homes.

Which step is your home on?

Hold the usage on your bill up against 200 and 400 (300 and 450 in July–August). Then you can see how fast your home's meter ran. If your home has just crossed a boundary, only the few dozen kWh over it get the higher price.

The place to watch is the basic charge. The basic charge switches as a whole, following the last step you reached that month. Cross 400 kWh (450 kWh in July–August), and it jumps from 1,600 won to 7,300 won. For a home that has just crossed this boundary, the extra money comes more from the basic charge than from the unit price. Divide the 5,700 won jump in the basic charge by the unit-price gap on the part over (92.7 won per kWh), and you get about 61.5 kWh (see the "Method" box below). So until the part over reaches about 61.5 kWh, the extra from the basic charge is bigger than the extra from the unit-price gap.

Numbers and method

Basic charge gap — 7,300 won − 1,600 won = 5,700 won (at the 400 kWh boundary; the same at the 450 kWh boundary in July–August).
Unit-price gap on the part over — third step 307.3 won − second step 214.6 won = 92.7 won/kWh.
Division — 5,700 ÷ 92.7 ≈ 61.5 kWh. If the part over is less than this, the basic charge side is bigger.
The 200 kWh boundary — the basic charge gap is 690 won (1,600 won − 910 won) and the unit-price gap is 94.6 won, so it flips at about 7 kWh. That is why the text talks only about the 400 kWh boundary.
100 kWh on each step — 100 kWh × the tariff table rate (120.0 · 214.6 · 307.3 · 736.2 won). 736.2 ÷ 120.0 ≈ 6.1.

Every summer brings stories about "easing the progressive tariff" and "electricity bill shock." Now there are just two questions to ask: did the width of the steps change, or did the price per unit change? A taxi meter doesn't tell you which speed it is on, but with electricity you can count it yourself — all you need is the usage line on your bill and the tariff table.

What to watch when you use these numbers

If you work out step prices in a report or an article, check three things.

The sums above cover only the basic charge and the energy charge. A real bill also adds the climate and environment charge, the fuel cost adjustment charge, the fund levy and value-added tax.
The tariff table has an effective date. When you compare a bill from another year, first check that it uses the same tariff table.
The wide summer steps (July–August) and the top step (over 1,000 kWh) do not apply in the same months (the wide steps only in July–August, the top step in July–August and December–February). If you don't check the month, the sum will be off.

But who sets this tariff table, and by what rules? Can KEPCO change it on its own? The answer is in "Who sets electricity prices, and how?"

Words in this piece

Progressive tariff A progressive tariff charges a higher unit price for the extra electricity used as consumption rises. Glossary → — a residential pricing method where the unit price of the part above each step rises every time usage crosses a step.
kW and kWh A kW (kilowatt) is a unit of power: how hard electricity is made or used at a moment. A kWh (kilowatt-hour) is a unit of energy: how much is made or used over time. Glossary → — the unit that measures how much electricity was used. The usage on your bill is printed in this unit.
Climate and environment charge The climate and environment charge is the line on a Korean power bill that shows policy costs such as renewable deployment and emissions reduction. Glossary → — a bill line that separately shows the costs of dealing with renewables and greenhouse gases.
Fuel Cost Adjustment Charge A bill item that passes changes in generation fuel prices through to electricity bills. Each month it adds usage multiplied by the fuel cost adjustment rate. Glossary → — a bill line that reflects ups and downs in fuel prices in the rate every quarter.

Source 1KEPCO (Korea Electric Power Corporation), *Residential (low voltage) tariff table* (「주택용 전력(저압) 요금표」, effective 9 Nov 2023, unofficial translation)See in sources →: KEPCO (Korea Electric Power Corporation), *Residential (low voltage) tariff table* (「주택용 전력(저압) 요금표」, effective 9 Nov 2023, unofficial translation) https://cyber.kepco.co.kr/ckepco/front/jsp/CY/E/E/CYEEHP00101.jsp Source 2Ministry of Trade, Industry and Energy (산업통상자원부), press briefing (13 Dec 2016)· press release (1 Jul 2019)See in sources →: Ministry of Trade, Industry and Energy (산업통상자원부), press briefing (13 Dec 2016) https://www.motir.go.kr/kor/article/ATCL3f49a5a8c/158887/view · press release (1 Jul 2019) https://www.motir.go.kr/kor/article/ATCL3f49a5a8c/161850/view Source 3Notice on detailed generation licensing criteria, electricity tariff calculation criteria, meter tolerance and grid operation (「발전사업세부허가기준, 전기요금산정기준, 전력량계허용오차 및 전력계통운영업무에 관한 고시」, unofficial translation) Art. 14,전기요금산정기준,전력량계허용오차및전력계통운영업무에관한고시/제14조 See in sources →: Notice on detailed generation licensing criteria, electricity tariff calculation criteria, meter tolerance and grid operation (「발전사업세부허가기준, 전기요금산정기준, 전력량계허용오차 및 전력계통운영업무에 관한 고시」, unofficial translation) Art. 14 https://www.law.go.kr/행정규칙/발전사업세부허가기준,전기요금산정기준,전력량계허용오차및전력계통운영업무에관한고시/제14조 Source 4KEPCO, *Notice of amendments to the Basic Supply Terms (new optional rate for general service (A) II)* (「기본공급약관 개정사항 안내(일반용(갑)Ⅱ 선택요금 신설)」, notice, 26 May 2026, unofficial translation)weekday off-peak, mid-peak and peak time bands apply to general service (A) II and (B), industrial (A) II and education (B).See in sources →: KEPCO, *Notice of amendments to the Basic Supply Terms (new optional rate for general service (A) II)* (「기본공급약관 개정사항 안내(일반용(갑)Ⅱ 선택요금 신설)」, notice, 26 May 2026, unofficial translation) — weekday off-peak, mid-peak and peak time bands apply to general service (A) II and (B), industrial (A) II and education (B). https://kepco.co.kr/home/media/newsroom/notice/boardView.do?boardMngNo=14&boardNo=2651