Rent + Utility Bill Calculator
Calculate rent, water and electricity by meter, then copy a bill to send your tenant on LINE. Free — no signup, no Excel.
Billing rates
MEA standard ~4.4
PWA standard ~18
e.g. common / trash fee
Room 1
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Did you know?
Per CPB Notice 2018, landlords with 5+ units must charge water/electric at the actual provider rate — no markup allowed. Penalty up to ฿100,000.
Read the full legal guide →What this free tool does
It's more than a utility calculator — enter each room's meter readings and rent, and it computes water, electricity, rent and service fees into one bill total, then gives you a message you can paste into LINE to send your tenant. A faster, free alternative to setting up an Excel sheet — nothing to install, works on your phone, no signup.
- Calculate water + electricity by meter
- Add rent + service fees into one total
- Copy a ready-to-send bill for LINE
- Free, no signup — up to 3 rooms
Frequently asked questions
How do I calculate a dorm's water and electricity bill?
Subtract last month's meter reading from this month's to get the units used, then multiply by the rate per unit (electricity ~4.4 THB/unit, water ~18 THB/unit). This tool does it automatically and adds the rent into one total.
Can this tool produce a bill / invoice to send the tenant?
Yes. After it calculates, you get a bill summary (rent + water + electric) you can copy straight into LINE. The full IslandDorm system also issues PDF invoices/receipts with a PromptPay QR.
How is it different from calculating in Excel?
No formulas to set up or break, works instantly on your phone, and it's free with no signup. It also keeps you compliant with CPB Notice 2018 (no markup on water/electricity).
Is it really free? Do I need to sign up?
Free, no signup, no email — up to 3 rooms. If you have more rooms or want the system to remember meters and bill the whole building, start a free 60-day trial.