When will energy unit rates change after an Ofgem review?
Ofgem updates the energy price cap on set dates — but your unit rates only change when your tariff updates. This guide explains the UK timings, what to expect on fixed vs variable deals, and what to do next.
- Price cap changes are scheduled (typically 1 January, 1 April, 1 July, 1 October)
- Most standard variable tariffs change on the day the new cap starts
- Fixed tariffs usually don’t change until your fix ends (unless your contract says otherwise)
Guide for UK households (not business energy). Rates shown are examples only and depend on region, meter type and payment method.
Fast answer: when your unit rates change after Ofgem’s review
In the UK, Ofgem reviews and sets the energy price cap on a schedule. The new cap (and the cap-level unit rates and standing charges) typically take effect on the first day of the quarter — 1 January, 1 April, 1 July and 1 October.
Whether your unit rates change on that date depends on the tariff you’re on:
Standard variable (SVT)
Usually changes on the cap start date (e.g., 1 April). Your supplier must tell you about changes, but the cap date is the key timing driver.
Fixed tariff
Unit rates typically stay the same until your fixed term ends. The cap may change, but your fixed unit rates normally won’t (check your contract).
Tracker / time-of-use
Rates can move more often (daily/half-hourly, depending on product). Ofgem cap still matters for SVTs, but trackers follow their own formula.
Key takeaway: The Ofgem review sets the cap level for the next period. Your unit rates change when your tariff updates — for most SVTs, that’s the same day the new cap starts.
What to check now (2 minutes)
- Are you on fixed, variable (SVT), tracker or time-of-use?
- Do you have a smart meter, prepayment meter or traditional meter?
- Is your region England, Scotland or Wales (Northern Ireland uses a different market and regulator)?
If you’re worried about changes
- Compare current deals before the cap date (availability varies).
- Check for exit fees if you’re fixed.
- Look at unit rate + standing charge, not just one number.
How to tell exactly when your unit rates will change
To work out when your unit rates will change after an Ofgem price cap review, you need two things: your tariff type and your tariff’s effective date (often shown on your bill, online account, or welcome email).
A simple rule of thumb
- If you’re on an SVT
- Your unit rates generally change on the day the new cap starts (1 Jan/Apr/Jul/Oct). Your supplier should notify you of any price change.
- If you’re fixed
- Your unit rates typically stay the same until the fixed end date. After that, many people move to an SVT unless they choose a new fix.
- If you’re tracker/TOU
- Your rates can change more frequently. Check the product’s terms (e.g., “daily tracker based on wholesale index” or half-hourly TOU).
Two realistic scenarios (with numbers)
These examples are illustrative to show timing and bill impact. Standing charges and unit rates vary by region, payment method and meter type. We assume a dual-fuel home on direct debit and an average split of electricity and gas use over a month.
Scenario A: You’re on an SVT
Assumption: New cap starts on 1 April. Your supplier updates SVT rates that day.
- Before 1 April: electricity 28p/kWh, gas 7p/kWh
- From 1 April: electricity 26p/kWh, gas 6.5p/kWh
- Monthly use (example): 250 kWh electricity, 900 kWh gas
Estimated impact on unit-rate costs:
Before: (250×£0.28) + (900×£0.07) = £133.00
After: (250×£0.26) + (900×£0.065) = £123.50
Difference: ~£9.50/month (standing charges not included).
Scenario B: You’re on a fixed tariff
Assumption: Your fixed tariff runs until 30 June. Ofgem’s cap changes on 1 April, but your fix stays the same until it ends.
- Your fix: electricity 30p/kWh, gas 7.5p/kWh (unchanged until 30 June)
- SVT from 1 April (example): electricity 26p/kWh, gas 6.5p/kWh
- Monthly use (example): 250 kWh electricity, 900 kWh gas
Estimated unit-rate comparison (while still fixed):
Fixed: (250×£0.30) + (900×£0.075) = £142.50
SVT example: £123.50
Difference: ~£19.00/month (before exit fees and standing charges).
If you have an exit fee, it can outweigh the short-term difference. Always check your tariff information label/contract.
Important: The price cap is not a cap on your total bill. It limits the unit rate and standing charge for typical use on default tariffs. Your bill still depends on how much energy you use.
Check deals while you wait (whole-of-market comparison)
If your SVT is due to change (or your fixed deal is ending), you can compare available tariffs using your postcode. We’ll show options from across the market where available, based on the details you provide.
Where to find your current tariff info
- Your latest bill PDF (often shows tariff name and end date)
- Your supplier online account (tariff section)
- Welcome email/letter when you moved in or last switched
Comparison: when rates change by tariff type (and what to do)
Use this table to map Ofgem’s cap timetable to your household situation. Exact dates and notifications can vary by supplier, but the pattern is consistent for most UK households on default tariffs.
| Tariff type | Does the Ofgem cap apply? | Typical rate change timing | Best next step |
|---|---|---|---|
| Standard Variable (SVT) | Yes (it sets max unit rates/standing charges by region/meter/payment) | Usually on 1 Jan / 1 Apr / 1 Jul / 1 Oct | Compare alternatives; check both unit rate and standing charge |
| Fixed | Not directly (your fix can be above or below the cap) | Typically at end of fixed term (unless contract allows changes) | Check end date + exit fees; line up a switch 2–6 weeks before it ends |
| Tracker | Varies (some are linked to wholesale; may have caps/floors) | Can change daily or on a defined schedule | Understand the formula; check risk if prices rise quickly |
| Time-of-use (e.g., Economy 7) | Often yes for default tariffs; TOU pricing structure adds complexity | SVT TOU rates often move with cap dates; smart tariffs can change differently | Check day vs night rates and your usage pattern before switching |
Decision checklist: who this suits
- SVT customers wanting clarity on the exact date prices move
- Households approaching a fixed tariff end date
- Anyone on prepayment or Economy 7 (where rates can differ materially)
- Renters/homeowners who need a simple plan before the next cap quarter
Who it may not suit (or needs extra checks)
- Northern Ireland households (different regulator/market; this page focuses on Great Britain)
- Homes with complex metering (multiple MPANs, heat networks, landlord supplies)
- Customers on legacy/tariffs with special terms (check contract wording)
- If you’re in debt repayment plans with your supplier (switching can be restricted)
Costs, exclusions and common pitfalls (UK-specific)
Most confusion after an Ofgem review comes from mixing up the cap date with your own tariff rules. Here are the gotchas we see most often.
1) Exit fees on fixed tariffs
Leaving early can trigger an exit fee (sometimes per fuel). If your fix ends soon, it may be cheaper to schedule a switch for the end date rather than paying to leave early.
2) Standing charges can rise even if unit rates fall
The cap covers both unit rates and standing charges. It’s possible for one to move up while the other moves down — your personal outcome depends on how much you use.
3) Region, meter type and payment method matter
The price cap varies by distribution region and between direct debit, standard credit and prepayment. Make sure you’re comparing like-for-like.
4) Prepayment meters: changes can feel delayed
If you top up at a shop or use a key/card, your meter may update when you next top up (depending on meter type). With smart prepay, updates can be remote, but not always instantly.
5) Moving home can put you on an SVT
When you move in, you’ll typically be placed on the existing supplier’s default tariff until you arrange a switch. That means your rates may follow the next cap change automatically.
Quick check: If you’re unsure which tariff you’re on, look for the words “Fixed”, “Standard Variable” or “Tracker” on your bill, or log into your supplier account. If you can’t find it, we can still compare options using your postcode and details.
FAQs
Does the price cap mean my bill is capped?
No. In Great Britain, Ofgem’s price cap limits the unit rate (p/kWh) and standing charge for default tariffs. Your total bill still depends on how much energy you use.
If Ofgem announces a new cap today, do my rates change today?
Usually not. Ofgem may announce the upcoming level in advance, but the new cap rates typically take effect on the next quarter start date (1 Jan/Apr/Jul/Oct). Your supplier then applies changes in line with your tariff type.
I’m on a fixed tariff. Can my supplier still change my unit rates?
A true fixed tariff normally keeps unit rates the same for the fixed term, but you should check your tariff terms for any clauses (for example, changes to VAT or certain policy costs). If the supplier proposes a change that disadvantages you, you may have rights to switch without penalty in some circumstances.
Why are my friend’s unit rates different to mine if we’re both on the cap?
Cap levels differ by region (network costs), payment method (direct debit/credit/prepayment) and meter type (including multi-rate). Your tariff may also include different standing charges.
Will my direct debit change automatically when the cap changes?
Not always immediately. Many suppliers review direct debits periodically based on your estimated annual use and account balance. Your unit rates can change on the cap date, while your direct debit may be adjusted later (or sooner if you’re building up debt/credit).
I have an Economy 7 / multi-rate meter. Does the cap still apply?
Default tariffs for multi-rate meters are still subject to cap rules, but the pricing structure (day/night) means comparisons are more sensitive to your usage pattern. When comparing, look at both rates and how much electricity you use overnight.
How long does switching take if I decide to change tariff?
Switching times can vary. In many cases, it’s around a few working days, but it depends on the supplier, meter details and whether there are any issues (e.g., address matching). You’ll usually stay supplied throughout — there’s no interruption to energy supply due to switching.
Does this apply in Northern Ireland?
Not directly. Northern Ireland has a different market and regulator (Utility Regulator) and does not follow the Great Britain Ofgem price cap in the same way. This guide focuses on England, Scotland and Wales.
Trust, methodology and sources
Page governance
- Written by: EnergyPlus Editorial Team
- Reviewed by: Energy Specialist
- Last updated: March 2026
How we assess “when unit rates change”
We base the timing guidance on Ofgem’s published price cap structure for default tariffs in Great Britain and standard supplier practice for updating SVT rates on the cap effective date.
Assumptions used in this guide:
- Applies to households in England, Scotland and Wales (not Northern Ireland).
- “Unit rates change on cap day” refers mainly to SVTs; fixed/tracker/TOU products can follow different rules.
- Example calculations exclude standing charges unless explicitly stated and are provided to illustrate direction and timing, not guaranteed savings.
Limitations: Individual supplier terms, meter configurations (e.g., Economy 7), regional network costs, and payment method can change the exact rates you see. If you’re in debt with your supplier or on certain support schemes, switching may have additional constraints.
Primary sources
- Ofgem: Energy price cap (policy and updates)
- Citizens Advice: Energy supply and switching guidance
- GOV.UK: Switching your energy supplier
We link to third-party sources for transparency. Their pages may be updated independently of this guide.
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