How to Legally Lower Your Tax Bill: Allowances in the US, UK and Canada
Tax planning sounds like something for the wealthy, but ordinary employees have more control over their tax than they think. The biggest levers are retirement accounts and other allowances that governments deliberately offer. This guide covers the main ones in the United States, the United Kingdom and Canada, with worked examples from our calculators. It is general information, not advice: rules depend on your circumstances, so check limits with your tax authority or a qualified adviser.
United States
- Traditional 401(k) or 403(b). Contributions come out of your pay before income tax. The 2026 employee limit is $24,500, with an extra $8,000 catch-up from age 50. Example: on a $100,000 salary, putting $10,000 into a traditional 401(k) reduces your federal income tax by about $2,200 (22% of the contribution). Social Security and Medicare are still charged on the full salary.
- Traditional IRA. The 2026 limit is $7,500 ($8,600 from age 50). Whether it is deductible depends on your income and whether you have a workplace plan.
- Roth accounts. No deduction now, but withdrawals in retirement are tax-free if the rules are met. A Roth is the better choice if you expect a higher tax rate later.
- Health Savings Account. If you have a qualifying high-deductible health plan, HSA contributions are deductible, growth is tax-free and withdrawals for medical costs are tax-free.
- Check your state. A few states have no income tax at all, and some exempt retirement contributions differently. See take-home pay in every state.
United Kingdom
- Workplace pension. Contributions are paid from pay before income tax (under net pay arrangements) or with tax relief added. The annual allowance is £60,000 for 2026/27. Example: a £50,000 salary with a £5,000 pension contribution cuts income tax and National Insurance by about £1,000 in total, so the pension costs you less than £5,000 of take-home pay.
- Salary sacrifice. If your employer offers it, giving up part of your salary in exchange for a pension contribution can also reduce National Insurance, for you and your employer. Check the rules on thresholds and minimum wage.
- ISAs. The £20,000 annual ISA allowance does not reduce your tax on pay, but interest, dividends and gains inside the ISA are tax-free.
- Marriage Allowance. If one partner earns less than the £12,570 personal allowance and the other pays basic-rate tax, up to £1,260 of allowance can be transferred, worth up to £252 a year.
- The £100,000 trap. The personal allowance is withdrawn between £100,000 and £125,140, giving an effective 60% rate on that slice. A pension contribution that brings your income below £100,000 can restore it.
Canada
- RRSP. The 2026 limit is 18% of last year’s earned income up to $33,810. Example: at an $80,000 salary in Ontario, a $5,000 RRSP contribution lowers your tax bill by $1,483.
- TFSA. Contributions are not deductible, but growth and withdrawals are tax-free. The 2026 dollar limit is $7,000, plus any unused room from earlier years.
- FHSA. The First Home Savings Account combines both: contributions up to $8,000 a year are deductible and qualifying withdrawals to buy a first home are tax-free.
- Childcare and disability credits. Childcare expenses can be deducted, and the Disability Tax Credit reduces federal and provincial tax. Both are options in our Canada calculator.
How much does each contribution save?
The saving is your marginal tax rate applied to the amount you contribute, so it differs by country and income. For the three examples above, the tax saved for every 1,000 contributed is:
Principles that work everywhere
- Use employer matching first. A matched contribution is an immediate return no allowance can beat.
- Know your marginal rate. A deduction saves your marginal rate on each unit contributed, so it is worth more in high brackets. The calculators show your marginal rate under Your Salary Insights.
- Do not let the tax tail wag the dog. A deduction saves tax, not money. Only contribute what you can afford to leave untouched until retirement.
- Keep records. Many credits, such as childcare, medical and donation credits, need receipts.
- Review every year. Limits and thresholds change each tax year, and so does your situation.
Model an RRSP, pension or family status and see the take-home pay change. Try the calculator →
Frequently asked questions
Is it legal to reduce your tax with pensions and allowances?
Yes. Retirement accounts, tax credits and allowances are written into tax law and exist to be used. This is tax planning, not evasion. Stay within the contribution limits and keep records.
How much tax does a 401(k) contribution save?
On a $100,000 salary, a $10,000 traditional 401(k) contribution cuts federal income tax by about $2,200. Payroll taxes for Social Security and Medicare are still charged on the full salary.
Does a UK pension contribution reduce National Insurance too?
Only if it is made through salary sacrifice. A normal personal or net-pay pension contribution reduces income tax but National Insurance is still charged on the full salary.
What is the difference between an RRSP and a TFSA?
An RRSP contribution is deductible now and taxed on withdrawal, so it suits people in a high bracket today. A TFSA gives no deduction but growth and withdrawals are tax-free, so it suits flexible savings and people expecting higher tax later.
Sources
- IRS, 2026 retirement plan limits (Notice 2025-67)
- GOV.UK, rates and allowances 2026 to 2027
- Canada Revenue Agency, RRSP, TFSA and FHSA limits
Figures are estimates for a single employee and are updated each tax year. This article is general information, not tax advice.