You can usually start comparing and agree a new business energy contract up to six months before your current one ends, without paying any early termination charge. Missing that window is what pushes most businesses onto deemed or out-of-contract rates — the most expensive tariffs a supplier offers. Here is how the timeline actually works.
Key takeaways
- Ofgem guidance allows business customers to switch from up to 6 months before contract end, without an early exit fee.
- Most suppliers require 30–90 days notice if you plan to leave rather than renew — check your specific contract.
- Missing your notice window usually means an automatic rollover onto a new fixed term, or a move to deemed rates.
- Your contract end date is on your bill or renewal letter — if you cannot find it, your current supplier can confirm it.
- Agreeing a new deal in advance locks tomorrow's contract at today's terms, protecting you from a last-minute price spike.
The switching timeline
| Time before contract ends | What you can do |
|---|---|
| 6 months | Start comparing the market; earliest point most suppliers will quote |
| 3 months | Sensible point to lock a new deal if rates look favourable |
| 30–90 days | Notice period deadline for most contracts — check yours specifically |
| 0 days (contract ends) | Automatic rollover to deemed/out-of-contract rates if nothing is agreed |
What is a notice period, and why does it matter?
Most business energy contracts include a notice period — a window, commonly 30 to 90 days before the contract ends, during which you must tell your current supplier if you intend to leave. Miss it, and many contracts automatically roll you onto a new fixed term at whatever rate the supplier sets, or onto a variable/deemed rate. Either way, you lose the leverage of comparing the market on your terms.
Check your contract, not just your bill
Your notice period is set out in your original contract terms, not necessarily on your bill. If you cannot locate it, your supplier is obliged to tell you when you ask — do this as soon as you start thinking about switching, not at the deadline.
What happens if you do nothing
- Automatic rollover — some suppliers roll you onto a new fixed contract at a rate set by them, not negotiated.
- Deemed rates — if there is no rollover clause, you default to the supplier's deemed rate, typically the most expensive tariff they offer.
- Out-of-contract rates — similar to deemed, applied when a fixed term simply lapses with no new agreement in place.
None of these outcomes are illegal or unusual — they are standard contract mechanics. But they are almost always worse for you financially than agreeing a new deal in advance, which is why tracking your end date matters more in energy than in most other business costs.
How to find your contract end date
- 1Check your most recent bill — many suppliers print the contract end date on it.
- 2Check your original welcome letter or contract confirmation email from when you signed up.
- 3Call your current supplier and ask directly — they are required to tell you.
- 4If you use a broker, ask them to confirm it and flag the date to you in advance.
Know your renewal date, on time
Send us your latest bill and we will confirm your contract end date, benchmark your rate against 30+ suppliers, and flag your renewal window in good time.
Get my free benchmark reviewFrequently asked questions
How far in advance can I switch business energy supplier?+
Typically up to 6 months before your current contract ends, without incurring an early termination charge. Some suppliers allow quotes further out, but 6 months is the widely used industry benchmark.
What happens if I miss my notice period?+
Depending on your contract, you will either be automatically rolled onto a new fixed term at the supplier's rate, or moved onto deemed/out-of-contract rates once the old contract lapses. Both are usually more expensive than a rate you negotiate in advance.
Can I switch supplier if I am already out of contract?+
Yes. If you are already on deemed or out-of-contract rates with no fixed term in place, you can switch or agree a new deal at any time — there is no notice period to wait out.
Does switching supplier cause a supply interruption?+
No. Switching business energy supplier is a change of who bills you for the same gas or electricity through the same physical connection — your supply is not interrupted during the switch.
About this guide
The mybusinessdeals energy team benchmarks UK business gas and electricity contracts against the whole market.