The deadlines for submitting your returns depend on how you file it. For the previous tax year, the important dates are:

• 5 October – You must inform HMRC by this date if you need to complete a tax return, and have not sent one before.
• 31 October – The deadline for submitting your self-assessment if you are doing a paper tax return.
• 31 January – The deadline for submitting your self-assessment if you are doing an online tax return.
• 31 January – The date by which you must pay all the tax you owe for the previous tax year.
• 31 July – This is usually the second payment deadline if you make advance payments towards your bill, known as “payments on account”.

In certain situations, you may not know your total profit for the entire tax year. For instance, this can happen if you’re waiting for a valuation. If you’re unsure of your final profit before the reporting deadline, you can use provisional figures and include these on your return.

Filing late typically incurs a penalty, though you may be able to appeal if you have a reasonable excuse. Even if you can’t pay the full amount by the deadline, you may be able to set up a payment plan and avoid incurring a charge.

To ensure accuracy and avoid penalties, it’s crucial to prepare your tax returns well before the deadline, so it’s a good idea to avoid leaving it to the last minute. Make sure you gather and assess all the necessary documents, such as P60s, P45s, invoices, and receipts, to account for all your income sources, and double-check your figures.

If you’re filing by post, be sure to factor in mailing delays. If you’re filing online, you can set up an account on the HMRC website.

There are many instances in which you may need to complete a self-assessment. It is your responsibility to determine if you need to.

If your adjusted net income – your total taxable income minus pension contributions – exceeds £150,000, you must submit a tax return.

This applies even if you owe no additional tax, and none of your income is from self-employment.

Some of your savings and investments (outside of tax-efficient options such as ISAs) may be liable for tax, meaning you may need to file a tax return.

For example, you might owe tax on interest from non-ISA savings that exceeds your Personal Savings Allowance (PSA), which is the amount of interest you can earn from savings before it is included in your income.

In the 2024/25 tax year, the PSA is:

• £1,000 if you’re a basic-rate taxpayer
• £500 if you’re a higher-rate taxpayer
• £0 if you’re an additional-rate taxpayer.

Any interest you earn above the PSA is liable for your marginal rate of Income Tax.

Additionally, if you hold dividend-paying investments outside an ISA, you may need to pay tax on the income they generate.

For the 2024/25 tax year, the Dividend Allowance is £500. This means any dividend income exceeding this threshold is subject to Dividend Tax. The exact amount you owe will depend on your marginal rate.

If you make a profit from selling certain qualifying assets, you may be required to pay Capital Gains Tax (CGT).

You may need to pay CGT if you make a profit when selling:

• Stocks and shares outside of an ISA
• A residential property that isn’t your main home
• Certain business assets
• Personal possessions worth more than £6,000 (excluding your car)

In 2024/25, you can make up to £3,000 of profit without paying CGT, which is your “Annual Exempt Amount”. Any profit above that may be liable for CGT at a rate based on your marginal rate.

In such cases, you’ll need to file a tax return to declare the gains to HMRC, and calculate the amount of tax you owe.

If you make a loss from selling or disposing of an asset, you may be able to offset it against any gains you make, potentially reducing the amount of CGT you owe. If your losses exceed your gains, you can carry the excess forward to offset against future gains. You can claim losses from up to four previous tax years.

So, even if you have no capital gains to report in the current tax year, it might be useful to file a return to claim and preserve any unused losses.

Other reasons you may have to complete a self-assessment tax return to cover the last tax year include if you:

• Were self-employed as a sole trader and earned more than £1,000
• Were a partner in a business partnership
• Had to pay the High Income Child Benefit Charge
• Received income from property rent
• Earned tips or commission
• Earned income from a foreign country

It’s important to remember that all the details here are based on our understanding of HMRC legislation, which is subject to change.

Although an Amber River financial planner can’t help you complete your tax return (that’s the job of your accountant), they can help you develop a financial plan that ensures you don’t end up paying more tax than you need to.

For example, they can help you structure your wealth in a way that reduces your tax exposure, by ensuring you make use of your available tax reliefs.

To speak to an Amber River financial planner about managing your wealth tax-efficiently, please get in touch. Call us on 0800 915 0000, or use our contact form here to set up an initial appointment.