How we check every number
Maintained by the MyPinoyTools Team · Last reviewed 9 August 2026
Every calculator here does the same thing: it reproduces a real bill, charge by charge, and we check the result against bills people actually received. Where a figure comes from a published rate schedule, we say so. Where we can't source something, we mark it unverified rather than present it as fact.
This page is where you check our work. It explains our approach — not a utility-by-utility rate dump, but how we make sure the number you see matches the number your utility would print.
How a bill is actually built
A residential bill is not one rate times your kWh. It's a set of separate charges, each computed on its own basis and taxed on its own terms. We reproduce that sequence exactly. In order:
- Compute each charge on its own basis, and round per line. Per-kWh charges scale with consumption; fixed charges are billed monthly. Rounding happens line by line, because the subtotals printed on a real bill are sums of already-rounded figures, not a single rounded total.
- Apply the local franchise tax to the charges it covers. Which charges are included, and at what rate, is set by your city. We take both from the published schedule rather than assuming one national figure.
- Apply VAT per component, at the billing month's actual rates. VAT here is not a flat 12% — parts of the pass-through charges are zero-rated, so the effective rate differs by charge and shifts month to month. We apply each charge's real rate for that month.
- Add the untaxed charges to reach the total. Universal charges and similar line items carry no VAT; they're added last to reach the figure our calculator targets.
Account-specific items — deposits, applied credits, arrears — sit outside this calculation. No calculator can predict them, so we take them as an optional input instead of guessing.
Different charges follow different rules
The same rate schedule can contain opposite mechanisms, and conflating them is the most common way to get a bill wrong. Some charges re-rate your entire consumption once you cross a threshold — the bracket you land in applies to every kWh, not just the ones above the line. Others work the opposite way: each band is charged at its own rate, and lower bands stay cheap. We model each charge as its own rule defines it, which is why our totals hold across the full range of usage. The exact thresholds and rates live in each utility's published schedule.
On VAT
VAT isn't a flat 12%. Portions of the pass-through charges are zero-rated, so the effective rate differs by component and changes every month. We read each component's actual rate from the billing month's schedule rather than applying a blanket percentage.
Things that are easy to get wrong
The local franchise tax varies by city
The official schedule sets this rate per local government unit, so it differs from one city to the next. The rate is set per city, which is why we ask rather than assume a single number. If your bill's franchise tax line shows a particular percentage, that is the one that applies to you, and our calculator lets you enter it.
“Lifeline” means two different things
The lifeline subsidy rate is a per-kWh charge paid by customers who are not lifeline beneficiaries to fund the programme. The lifeline discount is a reduction received by qualified households, at 100% below 50 kWh, 35% for 51–70 kWh, and 20% for 71–100 kWh.
These are separate mechanisms, and low consumption alone does not earn the discount. One of our validation bills used 87 kWh, squarely inside the 20% band, and was billed at full rates while still paying the subsidy charge, because the discount under Republic Act 11552 goes to registered qualified end-users. For that reason our calculator never applies a lifeline discount automatically from consumption, and we have not yet been able to validate the discount path against a bill from a registered household.
GEA-All is currently ₱0.0000
The Green Energy Auction charge appears on bills at zero because the Energy Regulatory Commission suspended collection through the August 2026 billing period, per its announcement of 29 June 2026. When charged, the rate on our validation bills was ₱0.0371 per kWh. The suspension has been extended twice on a two-month basis and is expected to be reviewed again, so we re-check it with every monthly rate update.
Appliance estimates
Appliance estimates use each device's rated wattage, its typical hours of use, and — for compressor-driven appliances like refrigerators and inverter aircon — a duty-cycle factor, because those units cycle on and off rather than drawing full power continuously. Costs use an effective rate per kWh derived from the current schedule: an average across the whole bill, not a single marginal rate.
Status: provisional. The preset wattages and duty-cycle factors are engineering estimates for typical Philippine models. We're verifying them against manufacturer and Department of Energy references; any preset we can't source will be corrected or removed. Duty-cycle factors are the least certain figures on this site.
How we validate
We test against real bills, transcribed line by line. A bill passes only when every printed figure matches ours to the centavo — not just the total, but every charge, every subtotal, every printed percentage, and the final energy amount. A bill changes shape with consumption, with the city, with the month, and with the layout the utility was printing at the time. We deliberately test across all of it:
| What we tested | Covered |
|---|---|
| Every consumption bracket | the full range of usage, from very low to very high, crossing every tier boundary a bill can have |
| Separate households | 6 different accounts, not one household's bills repeated |
| Different cities | 2 localities that charge different local franchise tax rates, so the tax structure itself is tested, not just one city's |
| Different rate months | 5 monthly schedules, covering generation, transmission and VAT rates that move every month |
| Different bill layouts | 3 formats the utility has used, including a transitional one that groups charges the old way but taxes them the new way |
| Independent checks | 4 bills whose rates came from a different source than the bill itself, and still matched exactly |
Those independent checks are the strongest evidence here. In one, the rates came from the utility's own published schedule; in the other, from a different household's bills in the same month. Both times the engine reproduced a bill its rate data had never seen. That is the difference between being correct and merely being self-consistent.
We would rather hold a handful of bills spread across every bracket, city and format than a hundred from a single household, because a hundred near-identical bills would test the same arithmetic a hundred times.
What we have not validated
What we have not validated: the lifeline discount path, for want of a bill from a registered lifeline household; bills with a meter multiplier other than one; and utilities we haven't yet sourced bills for.
Sources
- Utility Summary Schedules of Rates: each utility's residential schedule for the billing month, published monthly by the utility.
- Energy Regulatory Commission: orders and announcements affecting specific charges, including the GEA-All suspension announced 29 June 2026 and the distribution rate table set in ERC Case No. 2015-112 RC.
- Batas Pambansa Blg. 36: the energy tax brackets for residential customers.
- Republic Act 11552 and Republic Act 9994: the lifeline rate programme and the senior citizen discount.
- Real bills: real bills across multiple households and utilities, transcribed with personal details excluded.
Changelog
- 18 July 2026: Published the appliance electricity calculator with meter reconciliation. Documented that the lifeline discount requires registration and is not automatic below 100 kWh. Corrected our GEA-All citation to the ERC announcement of 29 June 2026.
- 17 July 2026: Transcribed the utility's official July 2026 schedule. Corrected the distribution charge to whole-consumption brackets and the energy tax to marginal brackets, having previously modelled both incorrectly.
- 16 July 2026: First validation of the bill engine against real bills; corrected VAT from a flat 12% to per-component effective rates.
Found something wrong? We would rather fix it than defend it. Corrections to any figure on this page are welcome, and we will note the change here.