How is the estimated cost of a tariff calculated?

When you register, we get your annual usage from your supplier via a regulated data energy hub. We estimate your annual costs based on these usage figures – yet your actual payments may differ.
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If you entered what you spend on gas and electricity, we use some assumptions to work out your usage, so the savings you see might not be bang on. Ultimately, the actual difference in what you pay each year will be small, and the cheapest suppliers will appear in the correct order.