Home / Business energy / Fixed vs flexibleLast reviewed June 2026
Fixed vs flexible business energy
Two ways to buy your business energy. A fixed contract locks your unit rate for the term, a flexible one moves with the wholesale market. Which fits comes down to your size, your appetite for risk and how closely you want it managed.
- You want one rate you can budget around for the whole term
- You would rather not have to watch the energy market
- Your usage is fairly steady and not especially large
- You use a lot of energy and want to buy it in tranches
- You can carry some risk in return for tracking the market
- You have the time, or an adviser, to manage the buying
Fixed and flexible are the two main ways a business buys its gas and electricity. A fixed contract sets your unit rate for the whole term, so you know what you are paying from day one. A flexible contract leaves your price to move with the wholesale market, which can work in your favour or against it. One is about certainty and the other about control, and the right answer depends far more on your business than on which is fashionable at the time.
Quick snapshot
- A fixed contract locks your unit rate for the term, while a flexible contract lets it move with the wholesale market.
- Fixed is simpler to budget around and suits most smaller businesses, while flexible can suit larger or high-usage sites that can manage the risk.
- Neither is automatically cheaper, since a fixed price usually carries a premium for the certainty it gives you.
- Flexible contracts need more management, whether you do it yourself or through an adviser.
What a fixed contract is
A fixed-rate contract sets your unit rate and standing charge for the length of the term, usually somewhere between one and five years. Whatever happens to wholesale prices after you sign, your rate stays where it is.
That makes budgeting straightforward, because the only variable left is how much energy you use. The trade-off is that the supplier prices in the risk it is carrying on your behalf, so a fixed rate usually sits a little above the market on the day you sign. You are paying for certainty, which for most smaller businesses is worth having.
What a flexible contract is
A flexible contract does not lock a single price. Instead you buy your energy in chunks across the term, often through a pass-through arrangement where the wholesale cost is passed on as it moves and the non-energy charges are billed separately.
It can work out well if the market falls or you time your buying carefully, and it gives larger users more control over how and when they purchase. The flip side is exposure. If wholesale prices rise, your costs tend to rise with them, and the contract takes more attention to manage.
Which one is easier to budget around
If predictable bills matter to you, fixed is the easier option by a distance. You agree a rate, and barring a change in how much you use, your unit cost does not move for the term. That makes forecasting simple and removes the job of watching the market.
A flexible contract asks more of you. Because the price moves, your budget has to allow for that movement, and someone needs to keep an eye on when to buy. For a finance team that wants one number to plan around, fixed usually wins.
Which one tends to cost less
Neither is automatically the cheaper choice, and anyone who tells you otherwise is guessing at the market. A fixed rate carries a premium because the supplier is taking on the price risk for you, so on a falling market a well-managed flexible contract can come out ahead.
On a rising market, the fixed rate you locked in can look like the better deal. The honest position is that the outcome depends on where the market goes and how actively a flexible contract is managed, neither of which is known in advance.
How much management each one needs
A fixed contract is close to set and forget. Once it is signed, the main thing left to do is line up the next one before it ends.
A flexible contract is the opposite. It needs ongoing attention to decide when to buy, how much to buy and when to sit tight, which is why larger users often run them with a procurement adviser rather than alone. If nobody in the business has the time or the appetite for that, fixed is the more realistic choice.
Who each one suits
As a rough guide, a fixed contract suits smaller and medium businesses with fairly steady usage that value certainty and simple budgeting. Flexible tends to make sense for larger or high-usage sites, the kind that spend enough for active buying to be worth the effort and can absorb some movement in price along the way.
Plenty of businesses sit between the two, and that is where a conversation with a broker helps, since the right structure depends on your usage profile rather than a rule of thumb. You can always compare business energy prices to see where you stand.
Fixed vs flexible at a glance
| Fixed contract | Flexible contract | |
|---|---|---|
| How the price works | Locked for the whole term | Moves with the wholesale market |
| Budgeting | Predictable, one rate to plan around | Variable, needs allowance for movement |
| Management | Largely set and forget | Needs active management or an adviser |
| Cost risk | A premium for certainty | Exposure to the market, down and up |
| Best suited to | Smaller and medium businesses with steady usage | Larger or high-usage sites that can manage risk |
| Typical term | One to five years | Often longer, bought in tranches |
Working out which one you need
For most smaller businesses, a fixed contract is the sensible default. It gives you a price you can plan around, it takes no managing, and the premium you pay for that certainty is usually money well spent against the stress of watching the market.
If your usage is large, your appetite for risk is higher, and you have the time or an adviser to manage the buying, a flexible or pass-through contract can give you more control and, in the right conditions, a better result. If you are not sure which camp you fall into, it is worth talking it through before you commit, and reading how to choose a business energy broker can help you find someone who will be straight with you about the trade-offs.
Frequently asked questions
Is fixed or flexible cheaper for business energy?
Neither is automatically cheaper. A fixed rate carries a premium for the certainty it gives, so a well-managed flexible contract can win on a falling market, while a fixed rate can win on a rising one. The outcome depends on where wholesale prices go and how actively a flexible contract is managed.
What is the difference between fixed and flexible business energy?
A fixed contract locks your unit rate and standing charge for the term, so your price does not change. A flexible contract lets the price move with the wholesale market, usually buying energy in tranches across the term. Fixed is about certainty, flexible is about control.
Is flexible energy procurement only for large businesses?
It is most common among larger and high-usage businesses, because active buying is more worthwhile at scale and they can carry the risk. Smaller businesses can use flexible or pass-through contracts too, but the management it takes often outweighs the benefit unless usage is significant.
Can I switch from a flexible contract to a fixed one?
Usually at renewal, yes. Many businesses move between the two as their usage, budget and view of the market change. The point to plan around is your contract end date, so you can line up the next arrangement before the current one rolls over.
Does a fixed contract protect me if prices rise?
Yes, for the length of the term. Once your rate is locked, a rise in wholesale prices does not change what you pay. The trade-off is that you would not benefit if prices fall during the term either.
What is a pass-through contract?
A pass-through contract is a form of flexible deal where the wholesale energy cost is passed on as it moves and the non-energy charges are billed separately rather than wrapped into one fixed rate. You can read more in our glossary entry on pass-through contracts.
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