Key money dates for October 2025

Stay on top of your finances with the important dates and deadlines coming up this month.

1 October – energy price cap increase

From 1 October, Ofgem's new energy price cap comes into effect.

For a typical household paying by direct debit, the annual cap is set at £1,755, a 2% increase from the previous cap of £1,720.

But remember, this is a cap on unit prices, not your total bill. What you pay depends on how much energy you use.

The new cap will remain in place until 31 December 2025.

If you’re worried about your energy bills or are falling behind on payments, don’t wait. Contact your energy supplier to see if you’re eligible for support, such as payment plans, hardship schemes, or government assistance from schemes like the Household Support Fund.

5 October - deadline to register for self-assessment

If you need to complete a tax return for the 2024/25 tax year and haven’t submitted one before, you must register with HMRC by 5 October.

This applies if you're:

• newly self-employed
• earning money from a side hustle
• a new landlord renting out property

You can register online via HMRC’s self assessment page.

22 October - September inflation rate announced

On 22 October, the inflation figure for September will be published.

This figure is especially important as it’s used to calculate changes to state pensions and benefits under the triple lock system.

The triple lock ensures the state pension rises each year by the highest of:

• inflation
• earnings growth
• 2.5%

The September inflation figure is the one that counts in this calculation.