How to reduce your UK tax bill legally

The legitimate ways to reduce a UK tax bill are all well-known statutory reliefs that HMRC explicitly designed and publishes: pension contributions, Marriage Allowance, ISAs and Lifetime ISAs, Gift Aid, salary sacrifice for non-pension benefits like cycle-to-work and EV leases, the capital gains annual exempt amount, the personal savings allowance, the dividend allowance, and the trading and property allowances. None of these are aggressive tax planning — they're routine reliefs that millions of UK taxpayers use every year. This page walks through each, with realistic expectations of what each one saves and where it applies.

Verified against 8 official sources · Last reviewed 23 May 2026
On this page
  1. A note on terminology
  2. 1. Pension contributions
  3. 2. Marriage Allowance
  4. 3. Individual Savings Accounts (ISAs)
  5. 4. Salary sacrifice for non-pension benefits
  6. 5. Gift Aid
  7. 6. Capital Gains annual exempt amount
  8. 7. Personal Savings Allowance
  9. 8. Dividend allowance
  10. 9. Trading and property allowances
  11. 10. The Rent a Room scheme
  12. 11. Pension Annual Allowance carry-forward
  13. Stacking these reliefs
  14. What this article isn't
  15. The bigger picture

A note on terminology

Before the list — a quick clarification of language. The methods below are statutory reliefs: HMRC explicitly designed each one to reduce specific tax liabilities, and using them is exactly what they're intended for. None of these are tax avoidance or aggressive planning. They're routine. Millions of UK taxpayers use multiple of these each year as standard practice.

The phrase "reduce your tax bill" sometimes implies aggressive structures, but for most UK PAYE workers, the reductions available are the ones below — well-known, widely-used, and explicitly sanctioned.

1. Pension contributions

The largest single reduction most workers can make. Pension contributions get tax relief at your marginal rate:

  • Basic-rate (20% IT): £20 saved per £100 contributed
  • Higher-rate (40% IT): £40 saved per £100
  • Inside £100k taper band: effectively £60 saved per £100 (because contributions also restore lost personal allowance)
  • Additional-rate (45% IT): £45 saved per £100

Salary sacrifice arrangements add a further National Insurance saving — 8% on contributions in the basic-rate NI band, 2% above. For a higher-rate taxpayer using salary sacrifice, the combined Income Tax and NI saving on each £100 of contribution is 42% — every £100 sacrificed costs about £58 of take-home.

The annual contribution limit for full tax relief is £60,000 (2026/27), tapered down for very high earners with adjusted income above £260,000.

For the mechanics, see salary sacrifice explained. For the relief specifics, pension tax relief explained.

2. Marriage Allowance

For couples where one earns below the personal allowance (£12,570) and the other is a basic-rate taxpayer (income £12,570–£50,270), Marriage Allowance transfers £1,260 of unused allowance to the higher earner. The annual saving is £252 — straight off the higher earner's tax bill.

Backdated claims of up to four years bring an additional one-off £1,008 for couples who've been eligible but not claiming.

Eligibility checked through HMRC directly or via the Marriage Allowance Checker, which models the £252 plus the backdated total. The application is free — never use paid services that charge a percentage of the refund for what HMRC offers free.

3. Individual Savings Accounts (ISAs)

ISA contributions are not deductible from income (so they don't reduce your Income Tax directly), but all interest, dividends and capital gains earned inside an ISA are tax-free. For a higher-rate taxpayer with substantial savings or investments, this is a major long-term reduction in tax exposure.

Annual ISA allowance: £20,000 per tax year across all ISAs combined. Variants:

  • Cash ISA — interest tax-free
  • Stocks & Shares ISA — dividends and gains tax-free
  • Lifetime ISA (LISA) — up to £4,000/year of the £20,000, with a 25% government bonus (up to £1,000/year) for first-time buyers or retirement saving from age 60
  • Innovative Finance ISA — peer-to-peer lending returns tax-free
  • Junior ISA for under-18s (separate £9,000 allowance)

For higher-rate taxpayers with savings interest above £500 (the Personal Savings Allowance — see below), moving cash from a regular savings account to a Cash ISA can save 40% on the interest. For investors expecting meaningful capital gains, a Stocks & Shares ISA shelters them from the 18-24% Capital Gains Tax that would otherwise apply.

4. Salary sacrifice for non-pension benefits

The same salary sacrifice mechanism that works for pensions also applies to certain other benefits. Common ones:

  • Cycle-to-work scheme — pre-tax bike and equipment up to £3,000+ (employer-set caps vary). Effective cost: 58-72% of the headline price for higher/basic-rate taxpayers
  • Electric vehicle lease — Benefit-in-Kind tax for fully electric company cars is just 3% in 2026/27 (rising 1% per year). EV sacrifice is exceptionally tax-efficient — a £40,000 EV often costs less per month in take-home than a £20,000 petrol car bought outright
  • Childcare vouchers — closed to new joiners since 2018, but existing scheme members can continue

For each, the tax saving comes from the same mechanism as pension sacrifice: the sacrificed amount avoids Income Tax and NI. The effective cost is your post-tax cost rather than the headline price.

5. Gift Aid

For UK taxpayers donating to UK-registered charities, Gift Aid is a tax relief on two sides:

  • The charity claims 20% basic-rate tax on your donation. A £100 donation becomes £125 for the charity.
  • Higher and additional-rate taxpayers can claim the difference between basic-rate (20%) and their marginal rate (40% or 45%) through Self Assessment. This is paid back to you, not the charity.

For a higher-rate taxpayer donating £100 under Gift Aid: - The charity receives £125 - The donor's effective net cost is £75 (after claiming £25 higher-rate relief) - That's 25% off the headline donation cost while increasing the charity's receipt

This makes Gift Aid one of the most efficient tax-reduction tools available to higher-rate taxpayers with charitable intent.

6. Capital Gains annual exempt amount

If you have assets that have grown in value (shares, investment property, second homes), Capital Gains Tax (CGT) applies when you sell them — but only on gains above the annual exempt amount, currently £3,000 in 2026/27 (reduced from £12,300 in 2022/23).

Practical implication: realising gains up to £3,000 per tax year produces no CGT. For larger gains, splitting disposals across multiple tax years can keep each year's gain below the £3,000 limit, or use jointly-owned assets to double the allowance to £6,000 across a couple.

For substantial portfolios, an ISA wrapper avoids the CGT entirely — see Section 3.

7. Personal Savings Allowance

UK taxpayers receive a tax-free allowance on savings interest:

  • Basic-rate taxpayers: £1,000 a year of savings interest tax-free
  • Higher-rate taxpayers: £500 a year
  • Additional-rate taxpayers: £0

For a basic-rate saver with £30,000 in a savings account earning 4%, the £1,200 of interest exceeds the £1,000 allowance — only £200 is taxable, at 20% = £40 tax. Moving £5,000 to a Cash ISA brings interest below the £1,000 allowance entirely.

For higher-rate savers, the £500 allowance is more easily exceeded — Cash ISAs become more relevant earlier.

8. Dividend allowance

Dividends from shares held outside an ISA get a separate £500 tax-free annual allowance (2026/27, reduced from £2,000 in 2022/23). Above the allowance:

  • Basic-rate: 8.75% dividend tax
  • Higher-rate: 33.75%
  • Additional-rate: 39.35%

For investors with dividend-paying shares, holding them inside a Stocks & Shares ISA exempts them entirely. For company directors paying themselves dividends, the £500 sits on top of salary in the tax stack.

9. Trading and property allowances

Two £1,000 allowances introduced in 2017:

  • Trading allowance: first £1,000 of trading income (small side hustle, occasional freelance work, eBay reselling above the casual-sales threshold) tax-free. If you earn under £1,000 from these, you may not need to register for Self Assessment.
  • Property allowance: first £1,000 of property income (renting out a spare room briefly, occasional Airbnb, small landlord activity) tax-free.

These are useful for people with very small secondary income streams who'd otherwise have to register for Self Assessment to declare a few hundred pounds.

10. The Rent a Room scheme

For homeowners renting a furnished room in their main residence, the first £7,500 a year of rental income is tax-free under the Rent a Room scheme. This is per property, not per landlord — couples split it 50/50.

For a homeowner renting a room at £600/month (£7,200/year), the entire income is tax-free under this scheme. Above £7,500/year, you can either pay tax on the excess or opt to be taxed under normal property income rules — whichever is more favourable.

11. Pension Annual Allowance carry-forward

If you haven't used the full £60,000 pension annual allowance in the previous three tax years, you can carry forward the unused portion to make a larger one-off contribution this year. Useful for:

  • One-off large contributions after receiving a bonus or inheritance
  • Catching up on pension saving after years of low contributions
  • Reducing a high tax bill in a specific year (e.g., a bonus year that pushes you into the £100k taper)

The mechanism is automatic if you exceed £60,000 in a single year and have unused prior allowance — the HMRC calculation uses available allowance from the oldest carry-forward year first.

Stacking these reliefs

The reliefs combine. A higher-rate taxpayer in 2026/27 might use:

  • 10% pension contribution via salary sacrifice (Income Tax + NI saving)
  • £20,000 ISA contribution (future interest and dividends tax-free)
  • Marriage Allowance via spouse (£252 a year)
  • Gift Aid on £600 of annual charity donations (£150 of higher-rate relief)
  • £3,000 of CGT-free gains realised before the tax year ends

Combined annual benefit: several thousand pounds in saved or sheltered tax, on top of the pension's long-term compound growth. None of this is aggressive — all are routine statutory reliefs used by millions of UK taxpayers.

What this article isn't

A few things deliberately excluded:

  • Aggressive structures (offshore trusts, loan arrangements, employee benefit trusts) — these are tax avoidance and HMRC actively challenges them
  • Tax evasion — not declaring income is illegal, not "reducing your tax bill"
  • Anything outside the routine reliefs — VCTs, EIS and similar carry meaningful investment risk and are out of scope for this general overview

For your specific situation — particularly if you have multiple income sources, business income, or substantial investment portfolios — a qualified accountant or Independent Financial Adviser can identify which of these reliefs apply and quantify the saving.

The bigger picture

Most UK PAYE workers have meaningful unused tax-reduction capacity. The auto-enrolment minimum 5% pension contribution captures only part of available pension relief. Many basic-rate savers don't think to move savings into ISAs. Marriage Allowance has ~2 million unclaimed eligible UK couples. These aren't sophisticated planning techniques — they're well-known reliefs that just haven't been activated.

For the most impactful single step, should I increase my pension contributions? is the first article most workers benefit from reading. Pension contributions deliver the largest single tax saving available to most PAYE earners, and the mechanism is well-understood.

Frequently asked questions

What's the difference between tax avoidance and tax planning?

Tax planning uses HMRC-sanctioned statutory reliefs (pension contributions, ISAs, Marriage Allowance, etc.) that are explicitly designed to reduce specific tax liabilities. Tax avoidance uses contrived arrangements that comply with the letter of the law but defeat its purpose — HMRC actively challenges these and they can be reversed retrospectively. Tax evasion is illegal. The reliefs in this article are all routine planning, used by millions of UK taxpayers.

How much can pension contributions reduce my tax bill?

Pension contributions get tax relief at your marginal rate. A basic-rate taxpayer saves £20 of tax per £100 contributed; a higher-rate taxpayer saves £40; an additional-rate taxpayer saves £45. For higher earners in the £100,000-£125,140 personal allowance taper band, the effective relief reaches 60-62%. Salary sacrifice adds NI savings on top: 8% for basic-rate, 2% for higher-rate.

Is Marriage Allowance worth claiming?

Yes if both partners qualify — it saves £252/year (£21/month), plus up to four years of backdated claims worth £1,008. Eligible couples are those where one earns below the £12,570 personal allowance and the other is a basic-rate taxpayer (£12,570 to £50,270). The Marriage Allowance Checker shows specific eligibility for your situation.

How much can I put in an ISA?

£20,000 per tax year across all your ISAs combined (Cash, Stocks & Shares, Lifetime, Innovative Finance). Lifetime ISA is sub-capped at £4,000/year of the £20,000. Money in an ISA is exempt from Income Tax on interest and from Capital Gains Tax on growth — useful for higher earners whose savings interest exceeds the Personal Savings Allowance.

What's Gift Aid and how does it reduce my tax bill?

Gift Aid lets registered charities reclaim 20% basic-rate tax on cash donations. For the donor, the donation also extends your basic-rate band — so for a higher-rate taxpayer, an additional 20% relief is claimed via Self Assessment. A £100 charitable donation under Gift Aid becomes £125 for the charity, and a higher-rate taxpayer effectively pays £75 of net cost for the £125 the charity receives.

Are these reliefs going to change?

Most have been stable for years. Personal allowance and higher-rate threshold are frozen through April 2031. Pension annual allowance was raised from £40,000 to £60,000 in 2023 and remains. ISA allowance has been £20,000 since 2017. Marriage Allowance has been £252 since 2015. The most likely changes in any future Budget would be at the margins (allowance freezes, threshold tweaks) rather than abolition.

Glossary terms used on this page

Quick definitions for the key terms above.

  • PAYE — The UK system through which employers deduct Income Tax and National Insurance from employees' pay before paying it to them.
  • Personal allowance — The amount you can earn each tax year before paying any UK Income Tax — £12,570 in 2026/27, frozen until April 2031.
  • Salary sacrifice — An arrangement where you give up part of your gross salary in exchange for a non-cash benefit (most commonly pension contributions), reducing your Income Tax and National Insurance.
  • Pension contribution — Money paid into a UK pension scheme by you, your employer, or both — eligible for tax relief at your marginal rate, up to the annual allowance of £60,000.

Sources

All figures on this page are sourced from official UK government publications. We don't cite secondary commentary or other calculator sites.

  1. GOV.UK — Income Tax: rates and allowances
  2. GOV.UK — Tax on your private pension contributions
  3. GOV.UK — Marriage Allowance
  4. GOV.UK — Individual Savings Accounts (ISAs)
  5. GOV.UK — Gift Aid
  6. GOV.UK — Tax-free allowances on property and trading income
  7. GOV.UK — Capital Gains Tax: annual exempt amount
  8. GOV.UK — Tax on savings interest

All tax figures on this page use the same configuration that powers our calculators — see our editorial standards for the review process.

Last reviewed: 23 May 2026. Next review due 23 November 2026.

Disclaimer: This page provides general information based on published HMRC and gov.scot figures. It is not personal tax or financial advice. For your specific situation, please consult a qualified accountant or contact HMRC directly.