When should you switch business energy?

When you switch business energy matters as much as who you switch to. Switch too late and you pay expensive rates while you sort it out. Switch too early, mid-contract, and you may pay an exit fee.

This guide explains the best time to switch, how early suppliers will let you lock in a new deal, when you can leave without a fee, and a timeline you can copy.

When is the best time to switch business energy?

For most businesses on a fixed contract, the best time is to have a new contract agreed before your fixed term ends, starting the day after. That is the one point in a fixed contract where you can move without an exit fee, and it avoids any gap on higher rates.

If you are not in a fixed contract at all, the best time is now. Citizens Advice says deemed and out-of-contract tariffs are usually very expensive, and that it is worth switching if you are on one.

How early can you switch business energy?

You can usually agree your next contract months before your current one ends. You are not switching early. You are agreeing a contract now that starts later.

Suppliers set their own windows:

• British Gas Business says it can give a renewal quote up to 12 months before your renewal date.
• EDF says you can usually start looking for a new supplier up to a year before your current contract ends. If you are in a fixed contract, EDF says the new contract starts the day after the current one ends.

Ask each supplier how far ahead it will quote, and how long its quote stays open. Starting early gives you time to compare, to watch the market on our wholesale prices page, and to meet any notice deadline.

Once you agree a contract, the switch itself is quick. The supply licences require suppliers to take all reasonable steps to complete a switch within five working days, unless you ask for a later date. That is how you line up a start date that matches your contract end date.

When can you switch without paying an exit fee?

At the end of your fixed term, and at any time if no fixed term applies to you. Here is where you stand in each situation:

Your situation	When you can switch	Exit fee
In a fixed term	At the end date, or earlier only if your contract allows	Usually charged if you leave early
Fixed term just ended	Straight away, after any notice your contract requires	None
Deemed contract, for example after moving in	Any time	Not allowed
Microbusiness on out-of-contract rates	Any time, no notice	None
Microbusiness in a rollover	Any time, no notice	None
Microbusiness on an evergreen (rolling) contract	Any time, with up to 30 days’ notice	None
Larger business rolled over or out of contract	Check your contract	Check your contract
Your supplier has gone bust	Once the new supplier is appointed	None

The microbusiness protections come from condition 7A of the gas and electricity supply licences. The deemed contract rules are in condition 7, which says a deemed contract must not have a fixed term, a termination fee or a notice requirement. Ofgem confirms that customers of a failed supplier can switch away from the replacement supplier without exit fees.

Can you switch in the middle of a fixed contract?

Sometimes, but it usually costs money. Ofgem says “most energy suppliers will not let you switch suppliers before the end of the contract”. Where a contract does allow early exit, it normally charges a fee.

Fees vary by contract. TruEnergy’s terms (version 2.7, June 2026), for example, charge the greatest of the estimated value of the rest of the contract, its losses from unwinding energy bought for you, or any exit fee in the contract, plus £100 per supply point.

A supplier can also object to your switch if your contract has a term allowing it, for example where you try to leave before the end date. Before you leave early:

1. Ask your supplier for the exit fee in writing.
2. Work out the saving on a new deal over the same period.
3. Only switch if the saving is clearly bigger than the fee.

Our guide to cancelling a business energy contract covers exit fees in detail.

What happens if you leave it too late?

Your contract terms decide, and it is usually more expensive. Ofgem says that if you do not change your contract before it expires, your supplier will automatically roll it over. In practice suppliers do different things:

• British Gas moves you to its Variable Price Plan, which it says tracks the market and may not be the best value.
• EDF automatically moves you to a variable tariff at the end of the fixed term, according to its June 2026 small business terms.
• Octopus Energy for Business moves you to its standard variable tariff unless you renew or give written notice.
• TruEnergy asks for at least 30 days’ notice. Without it, you may be charged its deemed tariff or rolled onto a 12-month contract.

If you are a microbusiness, a rollover cannot be longer than 12 months and you can leave during it without a fee. If you are a larger business, a rollover can tie you in until the new end date. See our rollover contracts guide.

Do you need to give notice before switching?

Microbusinesses do not. Since 1 October 2022, suppliers must not require a microbusiness to give any form of notice to end a fixed-term contract or switch supplier from the end of the fixed term. Ofgem said the change would give microbusinesses a smoother switching journey. The exception is an evergreen contract, where the notice period cannot be more than 30 days.

Larger businesses should check their contract. Missing a notice deadline can leave you on deemed rates or rolled onto a new term, as the TruEnergy example above shows. Put the deadline in your diary as soon as you know your end date.

When will your supplier remind you?

If you are a microbusiness, condition 7A requires your supplier to send, on or about 60 days before your fixed term ends:

• a statement of renewal terms, including your end date and what happens if you do nothing
• the principal terms that would apply after the end date
• your current charges and annual consumption

If it makes you renewal offers, at least one must be in writing and open until your fixed term ends. Some suppliers write earlier: EDF says it sends small business renewal letters 90 days before the end date, and British Gas says it sends a renewal deal 60 days before.

Do not wait for the letter. By 60 days out, you have lost much of the window you could have used to compare. Our contract renewal guide explains how to compare renewal quotes.

A switching timeline you can copy

Example: a business whose fixed electricity contract ends on 30 September 2027. The dates are worked out from that end date. Your contract and supplier may set different ones.

When	Date in this example	What to do
Up to 12 months before	From about 30 September 2026	Note the end date and any notice deadline. Some suppliers will quote from now
4 to 6 months before	April to June 2027	Gather bills, meter numbers and annual kWh. Start getting quotes
90 days before	2 July 2027	EDF-style renewal letters may arrive. Compare the renewal price with other quotes
60 days before	1 August 2027	Microbusiness renewal information is due
30 days before	31 August 2027	Last day for notice if your contract asks for 30 days
Before the end date	By 30 September 2027	Agree the new contract, starting 1 October 2027
First day of new contract	1 October 2027	Take a dated meter reading

Our contract renewal planner can help you set out the dates for your own contract.

Signs you should switch now

• You moved into your premises and never agreed a contract. You are almost certainly on deemed rates. See our change of tenancy guide.
• Your bill shows “variable”, “out of contract”, “deemed” or “default” rates.
• Your fixed term ended and you did not agree anything new.
• You are a microbusiness and have been rolled over. You can leave without a fee.
• Your supplier has failed and you are with the replacement supplier on its deemed rates.

In each case you can compare business energy quotes straight away. Our guide on how to switch business energy supplier walks through the steps.

Should you time the market?

No one can reliably tell you whether prices will be higher or lower when your contract ends. What you can control is having quotes in hand early, so you can fix when a price suits your budget rather than being forced to decide in the last week.

Remember what a fixed contract does. Ofgem’s advice for businesses says it charges a set rate per unit for the fixed term, but does not fix your total bill, which still goes up or down with your usage. If budget certainty matters most to you, having that rate agreed early in your window removes the last-minute pressure.

Large users have another option. Flexible contracts buy energy in stages rather than all at once. British Gas, for example, offers its Flex Advantage product to organisations using over 1 GWh a year. Our guide to fixed vs flexible contracts compares them, and our business energy prices page shows the latest average prices.

Frequently asked questions