Compare your current energy tariff with a new one. Find out exactly how much you could save by switching suppliers.
Calculate savings from switching to a new tariff
Savings shown are indicative. Check exit fees on your current contract before switching.
Switching energy suppliers is free, simple, and takes just 1-3 weeks. Millions of UK households switch every year to save money on their energy bills.
Switching energy supplier is one of the easiest ways to save money on your bills. The process is completely free, takes just a few minutes online, and your supply is never interrupted. The average household can save £150-300 per year by switching to a better deal, and some save much more.
The 4-Step Switching Process: (1) Find a new tariff you like on a price comparison website (Octopus, EDF, British Gas, OVO, Eon, etc. all have their own deals). Check the unit rate, standing charge, and contract length. (2) Start the switch online with the new supplier—they'll handle everything and ask for your account number and meter readings. (3) Wait 1-3 weeks while the switch completes. Your old supplier must release you within this time, and your new supplier must take over. (4) Your supply never stops—you'll seamlessly switch over, usually without even noticing.
Fixed vs Variable Tariffs: A fixed-rate tariff locks in your unit rates (p/kWh) for a set period—usually 1-3 years. This protects you if prices rise, but you'll be stuck at a higher rate if prices fall. A variable tariff follows the Ofgem price cap and resets every 3 months. Variable is cheaper when prices are falling but riskier if they spike. Most people fix for 1-2 years, then switch when the fix ends.
Best Time to Switch: The best time is as soon as you spot a better deal. However, check your current contract's exit fee. Some suppliers charge £30-60 to leave before your contract ends. Calculate whether the saving over your remaining contract justifies the exit fee. (Example: if you save £200/year but have an exit fee of £50, you break even in 3 months—worth switching.)
Green Tariffs: Most suppliers offer "green" or renewable electricity tariffs at little or no premium. These tariffs source electricity from renewables (wind, solar, hydro) and help fund new renewable projects. REGO certificates (Renewable Energy Guarantees of Origin) prove the renewable source. Any renewable tariff is better for the environment than a standard tariff, even if it costs the same.
What Happens During a Switch: Your new supplier contacts Ofgem's central switching system to request your transfer. Your old supplier is given 14 days notice. You should take meter readings on the final day with your old supplier and the first day with your new supplier—these readings prove who's responsible for what period. After the switch date, you'll receive final bills from both suppliers covering the transition period.
Price Cap Reference Framework: Ofgem's default price cap applies to all suppliers' standard variable rate (SVR) tariffs. The cap is set using the TDCV (Typical Domestic Customer Valuation) model, which uses 2,700 kWh electricity and 11,500 kWh gas per annum. Suppliers can offer cheaper fixed-rate deals below the cap and are not restricted from cheaper SVR offers either. Price cap resets quarterly (1 Jan, 1 Apr, 1 Jul, 1 Oct). The cap reset in January 2025 included a unit rate change of -1.2% electricity and +0.4% gas versus Q4 2024.
Switching Regulation and Central Switching System: Ofgem mandates the Central Switching Service (CSS) which operates the switching process. All suppliers must participate. The 14-day switching period is enshrined in the Electricity and Gas (Standards of Performance) Regulations 2015. Exit fees are capped by Ofgem and cannot exceed the genuine loss to the supplier (rarely more than £20-30). Time-of-use tariff switching (e.g., switching to Octopus Agile half-hourly) requires a smart meter or SMETS2 meter capable of half-hourly reads.
Switching Market Dynamics: In 2022-2023, 13.5m UK households switched suppliers (highest on record), driven by Ofgem price cap hikes. Supplier market share is fragmented: the "Big Six" (British Gas, Eon, EDF, Npower, Scottish Power, SSE) hold ~70% of retail market share, but smaller suppliers (Octopus, Bulb, OVO) have grown rapidly via switching deals and cheaper tariffs. The average tariff premium over the Ofgem cap is 8% (as of Q1 2025), meaning the average SVR is about 8% higher than the capped rate. This represents significant headroom for cheaper fixed-rate offers.
Tariff Comparison Methodology: The calculator uses a simple annual bill comparison: (Electricity Units × Unit Rate) + (Gas Units × Unit Rate) + (Electricity Standing Charge × 365) + (Gas Standing Charge × 365). This is the standard used by all comparison websites. However, suppliers may apply different standing charge premiums for payment method (Direct Debit ~0%, credit/cash +3-5%, prepayment +10-15%), and some regional variations exist in network charges (DNO DUoS rates). Tariff-level comparison should always include any sign-up discounts, loyalty discounts, or intro offers, as these significantly affect first-year costs.
Fixed vs Variable Economics: Fixed-rate contracts lock in a unit rate and standing charge for the contract term (typically 1-3 years). The supplier hedges wholesale energy prices on behalf of the customer. If wholesale prices rise, the customer is protected; if they fall, the customer overpays versus a variable tariff. The fixed-rate premium versus SVR typically ranges from 0% (in hot wholesale markets) to +5% (when suppliers are hedging expected future rises). Variable tariff tracking of Ofgem's price cap uses a ~6-8 week lag between wholesale market moves and cap resets, creating arbitrage opportunities during rapidly falling price periods.
Green Tariff Standards and REGO Certificates: A "renewable" or "green" electricity tariff commits the supplier to source a corresponding volume of electricity from renewable sources (wind, solar, hydro, biomass). This is proven via REGO (Renewable Energy Guarantee of Origin) certificates, each representing 1 MWh of renewable generation. REGOs are tradable and suppliers buy them to match their renewable claims. A "100% renewable" tariff means the supplier has purchased REGOs equal to 100% of that customer's annual consumption. REGOs cost ~£3-5 per MWh and are largely built into green tariff pricing. The environmental benefit of green tariffs is indirect (they fund renewable investment) rather than direct (you don't get "greener" electrons), but they meaningfully support renewable deployment.