Electricity per Unit in Thailand, Including VAT 2026 — 3.60 to 4.64 THB, not a single number
The rate table says 3.2484. Divide a real bill and you get 4.26. Most people conclude they are being overcharged. In fact both figures are correct and they are measuring different things. This page reconciles them by splitting the price you actually pay into four components, and says which of the four you can move and which you cannot.
No single number answers this, and that is the answer. In the May–Aug 2026 period a household pays 3.60 THB per unit if it uses 50 units a month, and 4.64 THB per unit at 800 — on the identical tariff, in the identical customer class. Three things stack up. One: the energy rate is progressive, so later units cost more. Two: there is a fixed monthly service charge that is not per unit, so a light user divides it across fewer units and the per-unit figure rises. Three: 7% VAT applies to the sum of everything, not to the energy line alone. This is why the rate table can never match the bill: the table is the bare energy rate, before Ft, before the service charge, before tax. And the 3.95 THB/unit figure quoted so often is the system-wide average, not your house. The way to get the real number is divide the amount due on the bill by the units — no rate table required.
What the all-in per-unit price is made of
A bill is always computed in this order: tiered energy charge, plus Ft at 0.1623 THB per unit, plus the monthly service charge, then 7% VAT over the whole subtotal. The table divides each of those by the units so you can see where the per-unit price comes from. Every cell is computed from the current period's real rates, not retyped.
| Units a month | Energy | Ft | Service charge | 7% VAT | All-in |
|---|---|---|---|---|---|
| 50 units | 3.04 | 0.16 | 0.16 | 0.24 | 3.60 |
| 100 units | 3.33 | 0.16 | 0.08 | 0.25 | 3.83 |
| 150 units | 3.46 | 0.16 | 0.05 | 0.26 | 3.93 |
| 200 units | 3.49 | 0.16 | 0.12 | 0.26 | 4.04 |
| 300 units | 3.74 | 0.16 | 0.08 | 0.28 | 4.26 |
| 400 units | 3.86 | 0.16 | 0.06 | 0.29 | 4.37 |
| 500 units | 3.97 | 0.16 | 0.05 | 0.29 | 4.47 |
| 800 units | 4.14 | 0.16 | 0.03 | 0.30 | 4.64 |
Read the table across and two things move in opposite directions. Energy per unit rises, 3.04 → 4.14 THB, because of the ladder. The service charge per unit falls, 0.16 → 0.03 THB, because a fixed lump is divided across more units. Ft per unit never moves at 0.1623 THB, because it is flat on every unit with no tiers. And VAT drifts up with the base it sits on. The net is a curve that climbs the whole way. For your own house, enter your units in the electricity bill calculator; if you already have the bill in hand, read it line by line at how to read the electricity bill.
The monthly service charge, and why light users feel it most
The monthly service charge is a constant per account and is not related to consumption at all: 8.19 THB a month for residential class 1.1 and 24.62 THB for class 1.2. (24.62 is the current figure — older numbers still circulating online are out of date.) Because it is a fixed lump, its effect on the per-unit price runs opposite to usage: a 50-unit household carries 0.16 THB of it per unit, an 800-unit household only 0.03 THB. Same line item, several times the impact. This is why a house closed all month still receives a bill, and why a very light-use rented room can compute an alarmingly high per-unit figure while sitting on exactly the same tariff as a large house.
Which of the four you can actually move
Energy — movable
The only component tied directly to behaviour — and because the tariff is progressive, any unit you remove comes off the topmost, most expensive tier. Cutting 50 units from an 800-unit house saves more than cutting 50 from a 200-unit house.
Ft — fixed
Announced by the ERC for each four-month period and applied to everyone identically — 0.1623 THB per unit this period. The only lever is knowing in advance whether the next period moves: what the Ft charge is.
Service charge — fixed
A constant set by your customer class, and the class is not something you choose — the utility assigns it from how the premises is used and the monthly volume: electricity customer classes.
7% VAT — fixed
A statutory rate applied to the sum of the three items above, so the only way it falls is if the base it sits on falls.
The constraint — these figures are not a price a landlord may set
The 4.64 THB/unit in the table above is what that customer pays the utility when consuming 800 units — not a price anyone may charge someone else, and not headroom remaining under the 4.88 THB/unit ceiling. The principle in the 2025 OCPB notification is that a landlord may not charge a tenant more than the utility charges the landlord. The 4.88 figure is the upper bound on that principle, not a licence to price at 4.88. Where a whole building's combined consumption pushes its bill to a high per-unit figure, the correct response is to divide what was actually paid, not to add another layer of margin. A tenant who suspects overcharging can check against the building's own bill: rental room and dorm electricity and reporting an overcharged rental bill.
When these numbers change
Two things move the table. First, a new Ft period — the ERC announces one every four months; the current one is May–Aug 2026. Second, the first-200-units-at-no-more-than-3.00-THB measure (มติ กพช. 2569), which takes effect with August 2026 consumption billed in the September 2026 cycle. The trap there is that 3.00 caps the energy rate, not the price paid: once Ft, the service charge and VAT are added, a household using exactly 200 units pays about 3.52 THB per unit, not 3.00. Detail: the first 200 units at 3.00 THB.
Who wrote this
Frank Lee, Founder of CapSolar — a commercial solar design-and-build company in Thailand with 80+ MWp installed across 150+ projects, 100+ clients served and 85K+ tons of CO₂ avoided. The all-in per-unit figure is the number we must get right before any assessment, because using the rate-table figure instead skews the entire result. This page runs on the same calculation engine we use in real work.
FAQ
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