# Joint Bank Account Taxation: UK 2025/26 Guide Understand the tax rules for UK joint bank accounts, including HMRC's 50/50 default split, declaring unequal ownership with Form 17, and personal allowances. **Published:** 2026-07-05 **Updated:** 2026-07-05 **Source:** https://aztajournal.com/gb/joint-bank-account-taxation --- > This guide covers the tax rules for UK joint bank accounts during the 2025/26 tax year. It explains HMRC's automatic 50/50 interest split, the processes for declaring unequal shares, and how separate tax bands and allowances apply to each individual's portion of savings income. In the UK, HMRC taxes joint bank accounts by dividing the total interest earned between the individual account holders, who are then taxed on their respective shares based on their personal circumstances. The account itself is never taxed as a single entity, and each holder must utilise their own available tax allowances to cover their portion of the interest. ## Key Takeaways - **Default 50/50 Rule:** HMRC automatically assumes that interest is split equally between joint account holders, meaning each person is liable for 50% of the tax. - **Personal Savings Allowance:** A basic rate taxpayer has a £1,000 allowance, a higher rate taxpayer has £500, and additional rate taxpayers receive £0. - **Form 17 Selection:** Married couples and civil partners must submit Form 17 to HMRC within 60 days if they want to declare an unequal actual split of beneficial ownership. ## How do joint bank accounts work for tax in the UK? Under UK tax law, HMRC assesses savings income on an individual basis rather than on a joint account wrapper. The total interest earned is split between the account holders first, and then each person's tax liability is calculated independently using their personal tax bands. This treatment means that one co-holder could owe tax on their portion of the interest while the other holder owes nothing. It prevents individuals from combining their allowances into a single joint pool, keeping all calculations strictly tied to each person's self-contained income details. ## What is the default split for tax on joint bank account interest? The default split for tax on joint bank account interest is an equal 50/50 division of all interest earnings between the account holders. This standard rule applies automatically to joint accounts in the UK unless a formal declaration of unequal beneficial ownership is submitted to and accepted by HMRC. For married couples and civil partners who live together, this equal division is legally codified under Section 836 of the Income Tax Act 1007 (ITA 2007 s.836). In everyday practice, HMRC also applies this 50/50 default split to accounts held by unmarried joint owners, such as siblings, business partners, or unmarried couples, regardless of who paid the funds into the account. ## How do I change the joint account tax split with HMRC? To change the default tax split with HMRC, you must demonstrate that your actual beneficial ownership matches the new unequal split you are declaring. The exact process to formally update HMRC depends on whether you are married or unmarried. 1. Establish that the actual beneficial ownership and funding of the joint account is unequal, matching the exact split you intend to declare. 2. For married couples or civil partners, complete and sign HMRC's Form 17 declaration under the Income Tax Act 2007 Section 837. 3. Submit the signed Form 17 to HMRC within 60 days of signature, alongside evidence of the unequal beneficial ownership structure. 4. For unmarried joint account holders, contact HMRC directly to notify them manually of the true unequal ownership split, as Form 17 is reserved exclusively for married couples and civil partners. ## How is each person's share of savings interest taxed? Once joint interest is divided, each person's share is taxed against three individual allowances applied in a specific priority order. These are the Personal Allowance, the Starting Rate for Savings, and the Personal Savings Allowance (PSA). The Personal Allowance of £12,570 is used first to cover any remaining non-savings income, with any leftover allowance applied to savings. The Starting Rate for Savings offers up to £5,000 of savings interest at a 0% tax rate under Section 12 of the Income Tax Act 2007 (ITA 2007 s.12). This 0% starting rate is designed for lower earners, shrinking by £1 for every £1 that non-savings income exceeds £12,570, meaning it is unavailable once salary or pension reaches £17,570. ### Personal Savings Allowance (PSA) bands for 2025/26 The Personal Savings Allowance is applied after other allowances under Section 12B of the Income Tax Act 2007 (ITA 2007 s.12B). It taxes interest within the allowance at a 0% savings nil rate, determined by individual tax bands. | Tax Band | Income Threshold | Personal Savings Allowance (PSA) | | --- | --- | --- | | Basic rate | Up to £50,270 | £1,000 | | Higher rate | £50,271 to £125,140 | £500 | | Additional rate | Over £125,140 | £0 | ### Example: How Alex and Sam's joint interest is calculated Alex earns a basic salary of £30,000, and Sam earns a higher salary of £60,000. They share a joint bank account that generates £2,000 in interest across the 2025/26 tax year, split equally under the default 50/50 rule. - **Total Interest Generated:** £2,000 total from the joint account. - **Alex's Share:** Receives £1,000 of interest. As a basic rate taxpayer, Alex has a £1,000 PSA. The allowance covers the entire share, resulting in **£0 tax** due. - **Sam's Share:** Receives £1,000 of interest. As a higher rate taxpayer, Sam has a £500 PSA. The allowance covers £500, leaving £500 taxable at 40%, resulting in **£200 tax** due. ## How does HMRC collect tax on joint account interest? HMRC collects tax on joint account savings interest through a combination of automated information feeds from financial institutions and direct manual tax returns. Taxpayers are responsible for verifying that these figures are attributed correctly. 1. UK banks and building societies automatically report all interest earned by account holders to HMRC at the close of every tax year. 2. For Pay As You Earn (PAYE) taxpayers, HMRC usually adjusts tax codes to collect any unpaid tax on savings interest automatically without requiring action. 3. Self Assessment filers must manually report their exact share of joint interest on their yearly tax return. 4. Taxpayers must review their P800 or Simple Assessment tax calculations, as automated HMRC systems occasionally mistake beneficial splits and assign 100% of the joint interest to just one person. ## Tax planning: Can I transfer savings to pay less tax? Yes, you can legally transfer savings or account registration to a lower-earning partner to reduce your household tax bill on interest. This strategy works by shifting interest income to a partner who has unused Personal Allowance or a higher Personal Savings Allowance. To satisfy HMRC, any such savings adjustments must represent a genuine change in beneficial ownership of the assets. The transfer cannot be a superficial arrangement solely to avoid tax, and the lower-earning partner must have physical and legal control over those funds. ### Do married couples have to split joint account interest 50/50 for tax? Yes, married couples must split joint account interest 50/50 as the default under section 836 of the Income Tax Act 2007. They can only use a different split if they genuinely own unequal shares of the underlying cash and formally report this to HMRC. ### What is Form 17 and when must it be submitted to HMRC? Form 17 is an official tax declaration used by married couples and civil partners to declare their actual unequal split of joint assets. It must be signed and submitted to HMRC within 60 days of the declaration date to be valid. ### What happens if HMRC attributes 100% of joint interest to one partner by mistake? If HMRC incorrectly attributes 100% of the joint interest to one person on a P800 form, you must contact HMRC directly. Provide evidence of the joint account status and request that the interest be corrected back to the default 50/50 split. ### Does the Starting Rate for Savings apply to joint bank accounts? Yes, the Starting Rate for Savings applies to each individual's portion of joint bank account interest. Eligibility depends on each holder's personal non-savings income falling below £17,570, rather than the combined household income.