Key money dates for October 2026: what you need to know

Autumn is here, and as the days get cooler, there are several important money dates you should have on your radar.

Here’s what you need to know and, where relevant, what you can do to prepare.

1 October – new energy price cap comes into effect

From Thursday 1 October, the energy price cap will increase by 4%, adding around £60 a year to the average household bill for customers paying by direct debit in England, Scotland and Wales.

The increase will affect you if you’re on a standard variable tariff, where the prices you pay can change in line with the price cap.

What can you do if you’re struggling with your energy bills

If you’re finding it difficult to keep up with your energy payments, don’t ignore the problem. Help may be available.

Depending on your circumstances, you might be able to:

• get emergency credit if you’re on a prepayment meter
• apply for a grant or hardship fund from your energy supplier
• join the Priority Services Register to access extra support

If you’re worried about your bills, contact your supplier as soon as possible to find out what help is available to you.

1 October – new tax on vaping products

A new tax on vaping products comes into effect on 1 October 2026.

Known as Vaping Products Duty (VPD), the tax will be charged at £2.20 per 10ml of e-liquid. Tobacco duty will also increase at the same time.

The measures are part of the government’s wider plans to reduce smoking, tackle youth vaping and encourage adult smokers to give up tobacco.

If you vape, the changes could affect the price you pay for vaping products.

5 October – deadline to register for self-assessment

If you need to file a self-assessment tax return for the 2025/26 tax year and haven’t registered with HMRC yet, 5 October is an important date for you.

You normally need to register by 5 October following the end of the tax year in which you first became liable to file a tax return.

If you register after this date, HMRC will give you a different deadline for submitting your return.

If you think you need to complete a tax return but haven’t registered yet, it’s worth checking your position as soon as possible.

21 October – inflation figures published

The latest Consumer Prices Index (CPI) inflation figures will be published by the Office for National Statistics (ONS) on 21 October, covering September 2026.

These figures are particularly important because the September inflation rate is used for some annual increases to benefits and, in some circumstances, the state pension.

So, while you may not notice an immediate change to your finances on 21 October, the figures could have an impact on your income from the following April.

28 October – autumn budget

The autumn budget will be delivered by chancellor John Healey on Wednesday 28 October 2026.

The budget is one of the biggest dates in the financial calendar, as the government can announce proposed changes to taxation, benefits and public spending.

You’ll want to keep an eye on the announcements if you’re concerned about how changes could affect your income, benefits, taxes or household finances.

In 2025, the budget included major changes like scrapping the two-child benefit limit and freezing tax thresholds.

But remember, budget announcements can be subject to parliamentary approval and may not take effect immediately.

31 October – paper self-assessment deadline

If you still file your self-assessment tax return on paper, 31 October is your deadline for submitting your return for the 2025/26 tax year.

Most people now file their tax returns online, but if you use a paper return, make sure you allow plenty of time for it to reach HMRC.

The online self-assessment deadline is later, giving you until 31 January 2027 to file your return and pay any tax you owe.

Keep these October dates on your radar

October could be an important month for your finances, with changes to energy costs and vaping taxes, key tax deadlines, new inflation figures and the autumn budget all happening within a few weeks.