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Thai Rental Room Electricity and Water Charge Calculator
Work out the maximum electricity and water rates a residential landlord may charge from its own utility bills, multiply by your room's sub-meter units and compare with the rate you are charged.
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Work out the maximum electricity and water rates a residential landlord may charge from its own utility bills, multiply by your room's sub-meter units and compare with the rate you are charged.
How it works
Under the 2025 Contract Committee announcement effective 4 September 2025, residential rental businesses must state electricity and water rates no higher than the utility charges them, and show the calculation. The OCPB guide divides the full amount on the landlord's bill (including service charge, Ft and VAT) by the units on that bill, then multiplies by the tenant's sub-meter units. This tool rounds the rate down to satang so it never exceeds the real average.
OCPB example: a THB 54,848.63 electricity bill for 11,237 units gives THB 4.88 per unit, so 100 units cost THB 488. A THB 454.75 water bill for 27 units gives THB 16.84, so 6 units cost THB 101.04. Charging THB 8 and THB 18 per unit would exceed the maximum by THB 318.96.
Applies to residential rental businesses within the announcement's scope and is not a legal ruling on any contract. Use the bill for the same period as the sub-meter reading. Rates change when the utility changes its tariff. Rent and other services with their own contract calculations are separate.
Frequently asked questions
Can a dorm charge THB 7–8 per unit?
Under the 2025 announcement the rate may not exceed what the electricity provider charges the business, so it depends on the building's real bill. If the bill's average is lower than the charge, the difference is the excess.
Why include VAT and Ft?
The OCPB example uses the full electricity amount the landlord pays, including energy, service charge, Ft and VAT, before dividing by units.
What if I cannot see the building's bill?
The contract must show how charges are calculated, and tenants may ask for supporting information. If you cannot get a verifiable answer, contact OCPB on 1166 or a Damrongdhama Center.
Sources
Rates last verified 21 Sep 2026