As of 13 August 2026, AI can choose between a fixed and variable energy tariff.

What to actually do

1. Hand it to a person

   The route this page recommends

   A person who owns the outcome does this end to end, worth it when the failure is dear.

2. Use a tool built for this

   Second choice

3. Do it yourself

   The distant third

   A chat interface, chat-fluent skill, and roughly 30 minutes until you can act on the result.

   How to actually do it

   1. Open your latest energy bill and supplier tariff information, then copy the electricity and gas unit rates, standing charges, usage figures, payment method, contract terms and any exit fee into a separate note.
   2. Collect the proposed fixed and variable tariff details from the supplier's current offer, including the rate type, review terms, contract length, standing charges, payment conditions and exit fee.
   3. Paste the collected figures into the prompt, replacing every bracketed slot and leaving any unavailable item marked as missing rather than guessing.
   4. Ask the chatbot to calculate the annual cost of each tariff from your actual usage and to separate usage charges from standing charges.
   5. Check every extracted rate and contract term against the supplier's current offer, then recalculate any total where the chatbot copied a figure incorrectly.
   6. Ask the chatbot to rerun the comparison with any corrected figures and to show only scenarios based on assumptions you explicitly provide about changing variable rates.
   7. Choose the tariff only after checking the final recommendation against your priorities for predictable bills, flexibility and the risk of paying an exit fee.

   Prompt

   Help me compare a fixed and a variable energy tariff in the UK. Do not invent rates, terms, dates, usage or savings. Use only the information I provide and label anything that is missing or uncertain.
   
   My recent annual electricity usage is [kWh], and my recent annual gas usage is [kWh]. If I only have monthly figures, state the conversion you use and keep it as an assumption.
   
   Current tariff:
   - Electricity unit rate: [pence per kWh]
   - Electricity standing charge: [pence per day]
   - Gas unit rate: [pence per kWh]
   - Gas standing charge: [pence per day]
   - Payment method: [method]
   - Contract end or review information: [details]
   - Exit fee: [amount or none stated]
   
   Fixed tariff:
   - Fixed period: [details]
   - Electricity unit rate: [pence per kWh]
   - Electricity standing charge: [pence per day]
   - Gas unit rate: [pence per kWh]
   - Gas standing charge: [pence per day]
   - Exit fee: [amount]
   - Other terms: [details]
   
   Variable tariff:
   - Rate type and review frequency: [details]
   - Electricity unit rate or pricing formula: [details]
   - Electricity standing charge: [pence per day]
   - Gas unit rate or pricing formula: [details]
   - Gas standing charge: [pence per day]
   - Exit fee: [amount or none stated]
   - Other terms: [details]
   
   First, list any missing information that could change the result. Then calculate the annual cost of each option using my stated usage, showing the electricity and gas calculations separately and showing standing charges separately. If a rate can change, do not predict it as a fact. Instead, show clearly labelled scenarios using only assumptions I approve, or explain why a scenario cannot be calculated. Compare the options on cost, certainty of bills, contract length, exit fees, payment terms and risks. State which option fits each of these priorities: lowest cost if rates stay as stated, predictable bills, and flexibility to switch. Give a cautious recommendation only after showing the calculations. Include a short checklist of every figure and contract term I must verify on the supplier's current offer before switching.

   Open it prefilled in ChatGPT or Claude, or copy it into Gemini, which takes no prefill link.