Cheapest fixed energy deal vs rolling contract (UK guide)
Find out whether a fixed tariff is likely to beat a rolling (standard variable) tariff for your home, what “cheapest” really means in the UK, and how to compare like-for-like.
- Clear UK definitions: fixed tariff, rolling contract, SVT and Ofgem price cap
- Realistic examples with numbers (standing charges + unit rates) and what can change them
- Trust-led comparison: meter type, payment method, region, exit fees and eligibility
Figures are illustrative and for guidance only. Your cheapest option depends on your usage, meter type, payment method, region and tariff terms.
Fast answer: is a fixed deal cheaper than a rolling contract in the UK?
Often, the cheapest fixed energy deal (when available) can beat a rolling contract (usually your supplier’s standard variable tariff, or SVT). But it’s not automatic: the “best” deal depends on your region, meter type, payment method, and your expected usage—plus whether the fixed tariff has exit fees and how long you want price certainty.
Important: In the UK, “cheapest” is usually measured by the estimated annual cost (unit rate × usage + standing charge × days). Two tariffs can look close on unit rates but differ meaningfully once standing charges are included.
Key takeaways
- Rolling contract usually means SVT: prices can change (typically with the Ofgem cap updates) and there are normally no exit fees.
- Fixed tariff gives a set unit rate/standing charge for a term (e.g., 12 months), but can include exit fees if you leave early.
- The cheapest deal for you will vary by region (distribution charges), meter type (credit vs smart/standard), and payment method (Direct Debit is often cheaper than pay on receipt of bill).
- To compare fairly, use the same usage assumptions and check standing charge, unit rate, contract length, exit fees and discounts/conditions.
When a fixed deal is more likely to win
- You value predictable bills over the next 12–24 months.
- The fixed tariff’s estimated annual cost is meaningfully lower than your current SVT.
- You can pay by monthly Direct Debit and have a standard credit or smart meter.
- You’re comfortable with a term commitment and any exit fee risk.
Quick definition: A “rolling contract” is commonly used to describe being out of contract on an SVT. Some suppliers may also offer fixed tariffs that roll onto an SVT at the end—always check the end-of-term outcome.
Compare fixed vs rolling (SVT) properly
To find the cheapest fixed energy deal compared with a rolling contract, you need a like-for-like estimate. UK prices vary because of regional network costs, VAT, and the way suppliers price by payment method and meter type.
What to gather (2 minutes)
- Postcode
- Sets your price region and network charges.
- Payment method
- Monthly Direct Debit, pay on receipt, or prepayment.
- Meter type
- Standard/smart credit meter, or prepayment meter (PPM).
- Usage (kWh)
- From your bill/online account, or use typical values cautiously.
What to check on any fixed deal
- Exit fees (gas, electricity, or both)
- Standing charge (p/day) and unit rate (p/kWh)
- Contract length and what happens at the end
- Eligibility (new customers only, smart meter required, etc.)
- Billing (e-billing discounts, paper bill charges)
Tip: If you can, compare using your last 12 months of kWh usage (not just £ spend). Price changes and credits can distort bill amounts.
How switching works (UK)
- Compare tariffs using your postcode, meter type and payment method.
- Apply to the supplier/tariff you choose (you’ll get a confirmation and key terms).
- Cooling-off period applies for most switches (you can cancel within the window).
- Switch completes without interruption to supply. Take meter readings on switch day.
- Final bill from your old supplier and your new account begins.
Get whole-of-market quotes
Start with your details and we’ll help you compare available fixed tariffs and rolling options for your home.
Not sure what you’re on now? If you’re out of contract and haven’t chosen a new tariff, you’re usually on your supplier’s SVT (a rolling tariff). Your bill or online account should confirm the tariff name.
Fixed vs rolling contract: what’s different?
Use this table to understand the trade-offs before you decide. Terms vary by supplier and tariff.
| Feature | Fixed tariff | Rolling contract (SVT) | What it means for you |
|---|---|---|---|
| Price certainty | Unit rate & standing charge fixed for the term (subject to T&Cs) | Can change (often when cap updates or supplier reprices) | Fixed helps budgeting; SVT can move up or down |
| Exit fees | Common (especially 12–24 month fixes) | Usually none | Exit fees matter if you may move home or switch soon |
| Discounts/conditions | May require Direct Debit, online billing or smart meter | Fewer conditions; default option | Check you can meet the criteria before applying |
| End of term | Often moves to SVT unless you choose another fix | Continues until you change it | Set a reminder to review before the fix ends |
| Best for | People who want stability and can commit to the term | People who want flexibility and no exit fees | Choose based on risk preference + your likely moving/switching plans |
Decision checklist: who a fixed deal suits (and who it doesn’t)
A fixed tariff may suit you if…
- You’ll stay in the property for the full term (or exit fees are low enough).
- You prefer predictability and don’t want prices changing mid-year.
- You can meet the tariff conditions (e.g., monthly Direct Debit, paperless billing).
- The fix is genuinely cheaper after you compare standing charge + unit rate.
A rolling contract (SVT) may suit you if…
- You might move soon, or you want the freedom to switch quickly.
- You don’t want to risk exit fees if better deals appear later.
- Your tariff options are limited (e.g., some prepayment situations) and flexibility matters.
- You’re waiting for smart meter installation or account changes before switching.
Two realistic UK scenarios (with numbers)
These examples show how “cheapest” is calculated. They are illustrative and not a promise of availability. We include standing charges because they can significantly affect the total.
Scenario A: medium-use dual fuel on Direct Debit
Assumptions (example): England/Wales region, monthly Direct Debit, credit/smart meter, annual usage 2,700 kWh electricity + 11,500 kWh gas.
| Item | Fixed example | SVT example |
|---|---|---|
| Electricity unit rate | 25.0p/kWh | 27.0p/kWh |
| Electricity standing charge | 50p/day | 55p/day |
| Gas unit rate | 6.1p/kWh | 6.7p/kWh |
| Gas standing charge | 28p/day | 30p/day |
| Estimated annual cost | £1,433 | £1,558 |
What this shows: with these assumptions, the fixed example is ~£125/year lower. If your usage is much lower/higher, the result can change.
Scenario B: low-use electricity-only flat
Assumptions (example): electricity-only, annual usage 1,800 kWh, monthly Direct Debit, credit/smart meter.
| Item | Fixed example | SVT example |
|---|---|---|
| Unit rate | 26.0p/kWh | 27.0p/kWh |
| Standing charge | 60p/day | 55p/day |
| Estimated annual cost | £684 | £687 |
What this shows: low usage means the standing charge dominates. A slightly cheaper unit rate might not help if the fixed tariff’s standing charge is higher.
Remember: Your actual bill depends on your kWh use, tariff rates, and any changes to your circumstances. If your direct debit is set higher than your current use, you may build credit even on a “cheaper” tariff.
Costs, exclusions and common pitfalls (UK-specific)
These are the reasons people think they’ve found the “cheapest fixed deal”, but the real cost ends up higher.
1) Exit fees on fixed tariffs
Leaving early can cost £—sometimes per fuel. If you might move or want to switch quickly, factor this into your decision.
2) Payment method differences
Monthly Direct Debit is often priced lower than paying on receipt of bill. Make sure your comparison is using your preferred payment method.
3) Meter type and tariff eligibility
Some tariffs are limited to smart meters or exclude prepayment customers. If you’re on a PPM, options can be narrower and priced differently.
4) Standing charges masking the headline rate
A lower unit rate can be offset by a higher standing charge—especially for low-use homes and electricity-only properties.
5) End-of-fix rollover
Many fixed deals revert to the supplier’s SVT. Set a reminder 4–6 weeks before the end date to review options.
6) Moving home mid-contract
Some suppliers may let you transfer a tariff to a new address, but it’s not guaranteed. Always ask before committing.
Price cap caveat: The Ofgem price cap limits the level of default (SVT) prices for a typical household, but your bill is not capped—it still depends on how much energy you use.
Mini-check before you switch to a fixed deal
- Confirm whether the rates are dual fuel or separate single-fuel prices.
- Check whether prices shown include VAT (5%) (they usually do for domestic tariffs).
- Look for exit fees and whether they apply per fuel.
- Make sure the tariff matches your meter and payment method.
- Read what happens at the end of the fix (SVT rollover, renewal options, notice periods).
FAQs: cheapest fixed deal vs rolling contract (UK)
Is a rolling contract the same as an SVT?
In most UK household cases, yes: “rolling contract” commonly means you’re on a supplier’s standard variable tariff (SVT) after a fix ended or if you never chose a fixed tariff. The SVT price can change over time.
Does the Ofgem price cap make SVTs the cheapest?
Not necessarily. The cap limits SVT pricing for a typical household, but fixed deals can be priced below (or above) SVTs depending on market conditions. Always compare the estimated annual cost for your home.
Why do prices differ by postcode in the UK?
A portion of your bill is made up of regional network charges (electricity distribution and gas transportation). These vary across Great Britain, so the same tariff can cost different amounts in different regions.
Can I switch if I’m in debt to my supplier?
Sometimes. Rules can depend on the debt level, how it’s being repaid, and whether you’re on a prepayment meter. If you’re struggling, it’s worth getting independent help from Citizens Advice and speaking to your supplier about support options.
What if I have a prepayment meter (PPM)?
PPM tariffs can be priced differently and there may be fewer deals. Some fixes may require a credit meter or smart meter. Compare using your exact meter type so you don’t see prices you can’t take.
Are “new customer only” fixed deals worth it?
They can be, but check the full cost: eligibility, payment method, standing charge, and exit fees. Also check what happens at the end of the term and whether the supplier’s SVT is competitive if you forget to switch again.
Will switching interrupt my gas or electricity?
No—your supply stays on. The switch is administrative. You may be asked for (or should provide) meter readings around the switch date to make sure the final and opening bills are accurate.
What’s the biggest mistake when choosing the “cheapest” fixed deal?
Looking only at the unit rate. The standing charge and your usage level can change the outcome. Always compare the estimated annual cost and read the key terms (especially exit fees and eligibility).
Trust, methodology and sources
Page details
- Written by
- EnergyPlus Editorial Team
- Reviewed by
- Energy Specialist
- Last updated
- June 2026
How we assess “cheapest fixed deal vs rolling contract”
We assess value using the UK-standard approach: estimated annual cost = (unit rate × annual usage) + (standing charge × 365). We focus on factors that commonly change the ranking of deals:
- Region/postcode (network costs and tariff availability)
- Payment method (Direct Debit vs pay on receipt vs prepay)
- Meter type (credit/smart vs prepayment; electricity-only vs dual fuel)
- Tariff terms (contract length, exit fees, eligibility conditions)
Limitations: Market prices and supplier availability can change quickly. The examples on this page are not live quotes and do not reflect every supplier or tariff. Always confirm final rates and fees at application.
Ready to check the cheapest option for your home?
Compare fixed tariffs against rolling (SVT) prices using your postcode, meter type and payment method—then switch if it suits you.
Back to Guides & FAQs