Why has my electricity bill increased when my usage hasn’t?
Find out whether the difference comes from prices, billing dates, expired discounts or other charges.
By Otria · Updated:
1. Do the bills cover the same number of days?
Two bills arriving a month apart do not necessarily cover equally long periods.
Check the start date, end date and number of days billed. A longer period can mean more consumption and higher charges calculated per day.
To compare your everyday electricity use, divide consumption by the number of billing days:
| Previous bill | New bill | |
|---|---|---|
| Days billed | 28 | 35 |
| Electricity used | 280 kWh | 350 kWh |
| Average daily consumption | 10 kWh | 10 kWh |
In this example, your daily use has stayed the same, but the second bill covers seven more days.
Illustrative example.
2. Has the price per kWh changed?
Find the energy section of both bills and compare the rates in €/kWh.
If you have several prices by time period, compare each one. Check whether the bill splits the period into dates with different rates.
A higher energy charge may reflect:
- New prices following a contract renewal.
- Changes under an indexed or dynamic pricing formula.
- The end of a promotional rate.
If your contract has fixed prices, do not assume an unexplained increase is correct. Compare it with the agreed terms and ask the supplier to explain the difference. Fixed-price contracts have protections against price changes during their term, with separate treatment for applicable regulated components.
3. Has a discount ended?
Look for wording such as descuento, promoción or bonificación.
Check what the discount covered and whether it still appears. A promotion might apply only to the energy charge, only for the first few months or only while another condition is met.
A bill can rise when a discount ends even if the underlying rate and your consumption stay the same.
Compare the amount after discounts, not just the rate printed above them.
4. Did you use electricity at more expensive times?
The same total kWh can cost different amounts if your tariff’s prices vary by time.
For example, moving some consumption from a cheaper period to a more expensive one can increase the energy charge without increasing total consumption.
Check the consumption and prices for each period. If you pay one energy rate throughout the day, this particular explanation will not account for a change in that charge.
For tariffs linked to changing market prices, the prices during the billing period also matter.
5. Have power charges or extra services increased?
Your bill includes costs beyond electricity consumption.
Compare:
- Contracted power: the kW recorded in each applicable period.
- Power rates: the price charged for that capacity.
- Billing days: relevant to charges calculated per day.
- Additional services: maintenance, assistance or repair cover.
- Meter rental and other listed charges.
A previously free service may now have a monthly charge. An extra product may also be billed separately from the electricity supply.
If you do not recognise a service, ask the supplier when and how it was contracted and request its terms.
6. Are there adjustments, credits or different taxes?
Check whether either bill includes a correction relating to an earlier period. Look for wording such as regularización, ajuste or abono.
Also check whether the meter readings are marked actual — real — or estimated — estimada. An adjustment after an estimated reading can make the amount paid different from a straightforward charge for the latest period.
Compare tax rates and amounts too. A larger tax amount does not necessarily mean the tax rate increased: it can also result from higher taxable charges.
If an adjustment is unclear, ask which dates, readings and earlier invoices it relates to.
A simple example: the same consumption, a higher cost
Imagine two bills covering the same period length, both with 300 kWh of consumption.
| Illustrative charges before taxes | Previous bill | New bill |
|---|---|---|
| Energy rate | €0.12/kWh | €0.16/kWh |
| Energy charge | €36 | €48 |
| Additional service | €0 | €5 |
| Subtotal of these items | €36 | €53 |
These two items alone account for a €17 increase before taxes, despite unchanged consumption.
This example does not include power charges, meter rental or every bill component. The prices are illustrative, not current offers.
What should I ask the supplier?
If you cannot explain the increase, send both invoice references and ask:
My electricity consumption is similar, but my bill has increased. Please identify which rates or charges changed, when they changed and the contractual basis for the change. Please also explain any expired discounts, additional services or billing adjustments.
Keep the reply and any complaint reference. If the explanation does not resolve the issue, follow the supplier’s formal complaints procedure and the official consumer guidance.
Common questions
Does a higher bill mean I need to change supplier?
No. First establish the cause. A longer billing period or a one-off adjustment is different from a more expensive ongoing tariff.
Why has my bill increased if I have a fixed-price plan?
Fixed energy prices do not mean a fixed total bill. Check consumption, billing days, discounts, services, taxes and regulated components. Any unexplained change to the agreed energy rates should be queried.
Can an official tool help me understand the bill?
The CNMC’s “Entiende tu factura” tool explains bill components and contract information. Where your bill provides the CNMC QR code or comparison link, you can use it to access the tool.
See whether another plan fits your home
Once you understand the increase, compare alternatives using the same consumption and billing period.
Otria uses your electricity bill and household preferences to compare eligible offers, explain why they fit and estimate what you could pay.
An estimate is not a guaranteed saving. You decide whether to switch.
Find a better tariff for me →