Self-Employed Tax Deductions Checklist (Don't Miss These)
A checklist of commonly missed tax deductions for the self-employed — from home office and mileage to professional subscriptions, bank charges and pension contributions — so you don't pay more tax than you owe.
The short answer
Commonly missed self-employed deductions include a proportion of home and phone costs, business mileage, professional subscriptions and insurance, bank and finance charges, training that maintains existing skills, use-of-home flat rates, and pension contributions (claimed personally, not as a business expense). Recording them all digitally keeps your MTD profit accurate and your tax bill fair.
Most self-employed people don't pay too little tax — they pay too much, because they forget legitimate deductions. Run through this checklist so your MTD profit reflects your real costs.
Everyday costs that add up
- Home office — actual proportion of bills, or HMRC's flat rate.
- Phone & broadband — the business share.
- Software & subscriptions — accounting tools, design apps, cloud storage.
- Bank & card fees — business account charges, payment-processing fees.
- Postage, packaging & stationery.
Getting around
- Business mileage at HMRC's approved rates, or actual vehicle running costs (not both).
- Public transport, parking and tolls for business journeys.
- Accommodation and subsistence on business trips away from your base.
Professional and financial
- Professional subscriptions to approved bodies.
- Business insurance — public liability, professional indemnity, contents.
- Accountancy and legal fees for the business.
- Interest and charges on business loans and finance.
Easily forgotten
- Use-of-home flat rate even if you thought you couldn't claim.
- Protective clothing and uniforms (not everyday clothing).
- Training that maintains skills you already use.
- Bad debts you've genuinely written off.
- Pension contributions — not a business expense, but they reduce your income tax through relief on your final declaration, so capture them.
A quick self-check
| Ask yourself | If yes… |
|---|---|
| Did I pay for it to run the business? | Likely allowable (business share) |
| Is it partly personal? | Claim only the business proportion |
| Is it a subscription/fee I forget? | Add a recurring entry so it's never missed |
Make it automatic
The reason deductions get missed is that people reconstruct expenses months later. Under MTD you're recording digitally anyway — enter costs as they happen and the small stuff stops slipping through.
ThisQuarter keeps every expense category from HMRC's schema in one place, so when you review a quarter you can see at a glance where a category is suspiciously empty.
Key takeaways
- The biggest tax leak is missed deductions, not overclaiming.
- Capture home, phone, software, bank fees, mileage, subscriptions and insurance — the everyday costs.
- Remember pension contributions separately — they cut tax via relief.
- Record as you go so nothing is forgotten at year-end.
This article is general information, not tax advice. Check HMRC's expenses guidance at gov.uk or speak to your accountant.
Frequently asked questions
What deductions do people most often miss?
Home-office costs, business mileage, professional subscriptions, bank and card fees, software, and a share of phone and broadband. Individually small, together they can knock a meaningful amount off taxable profit.
Are pension contributions a business expense?
No — for a sole trader, personal pension contributions aren't a business expense, but they still reduce your income tax through pension tax relief, claimed on your final declaration. It's a deduction worth capturing separately.
Can I claim training courses?
Training to maintain or update skills you already use in your business is generally allowable. Training to acquire a brand-new skill or start a new trade usually isn't. Keep evidence of the purpose.
How do I make sure I capture everything?
Record expenses as they happen in your MTD software rather than reconstructing them at year-end. Real-time entry is how the small, easily-forgotten costs actually get claimed.
Related reading
Allowable Expenses for the Self-Employed: A Plain Guide
What counts as an allowable business expense when you're self-employed — the main categories HMRC accepts, what's disallowed, the 'wholly and exclusively' test, and how expenses feed your MTD quarterly updates.
Simplified Expenses and Mileage for the Self-Employed
How HMRC's simplified expenses work — flat rates for vehicle mileage, working from home and living on business premises — when they beat working out actual costs, and how they fit with MTD.
MTD for Income Tax Explained for Sole Traders (2026 Guide)
A plain-English guide to Making Tax Digital for Income Tax for sole traders — who's affected, what changes, what you have to do each quarter, and how to get ready before April 2026.