Why thousands of francs are «gifted» to the tax authority
In Switzerland, a sole proprietorship pays tax on net business income: revenue minus all professionally justified expenses (Art. 52 TPA). There is no convenient flat rate as for some employees: if you do not include an item in the income statement attached to your return, that expense does not exist for the cantonal authority.
Fiduciaries reviewing hundreds of returns confirm the same pattern: over 90% of the self-employed forget at least three categories of deductible costs — especially mixed shares (home, car, phone), digital subscriptions and «small» expenses accumulated during the year. At an average marginal rate of 25–35%, CHF 5,000 of forgotten deductions means CHF 1,250–1,750 of extra tax paid.
This guide lists the most often omitted items, with typical tax savings and correct documentation. It does not replace cantonal advice: some cantons apply different limits for home office or business meals.
Overview: what is forgotten and what it costs
Indicative amounts for self-employed with CHF 80,000–120,000 net income and ~30% marginal rate. Your situation may vary.
| Often forgotten deduction | Typical amount/year | Tax saving ~30% |
|---|---|---|
| Home office (rent, utilities) | CHF 2,000–4,000 | CHF 600–1,200 |
| Private car kilometres (0.70/km) | CHF 1,500–3,000 | CHF 450–900 |
| Phone, internet, cloud | CHF 800–1,500 | CHF 240–450 |
| Software and SaaS subscriptions | CHF 600–2,000 | CHF 180–600 |
| Training and conferences | CHF 1,000–3,000 | CHF 300–900 |
| Professional liability and associations | CHF 500–1,200 | CHF 150–360 |
| Fiduciary and bank fees | CHF 1,000–2,500 | CHF 300–750 |
| Depreciation PC, phone, furniture | CHF 500–1,500 | CHF 150–450 |
Office and home: shares nobody calculates
Those working from home — most Swiss freelancers since 2020 — can deduct a professional share of rent and utilities, not the full amount.
1. Professional share of rent (home office)
Forgotten because rent is paid from a personal account without calculating floor space: e.g. 15 m² office on 100 m² home = 15% of annual rent deductible.
On CHF 24,000 annual rent, 15% = CHF 3,600 deduction → ~CHF 1,000 less tax.
Measure the room, document exclusive professional use (photos, floor plan). Enter in income statement as «professional rent share». Some cantons cap at 20% of total rent.
2. Electricity, heating, water (office share)
Bills stay in the private drawer. Without allocation, utilities never enter accounts.
CHF 200–600/year additional deduction using the same % as the office.
Apply the same % as rent to annual utility bills. Keep all provider invoices.
3. Home office furniture and equipment
Desk, ergonomic chair, monitor: bought privately and never depreciated in accounts.
CHF 500–1,500 annual depreciation (furniture 25%, equipment 30% per FTA practice).
Register as fixed asset with depreciation schedule. Invoice to business or professional allocation note.
Mobility: private car and business travel
Company cars are rare in small sole proprietorships. The private car is used — and almost nobody keeps a mileage log.
4. Business kilometres (CHF 0.70/km)
Client visits, deliveries, sites: thousands of km per year without a log. Only fuel is guessed, which is incomplete and harder to defend.
4,000 km × CHF 0.70 = CHF 2,800 deductible → ~CHF 800 tax saved.
Mileage log with date, destination, client, km. Alternative: actual costs with private use allocation (min. 9.6% of purchase price/year for private car share).
5. Parking, tolls, public transport for business
Small amounts on Twint or personal account: not aggregated, they disappear.
CHF 300–800/year often recoverable.
«Mobility» folder in software; link each charge to a documented client appointment.
6. Meals on business trips (actual, not employee flat rate)
Self-employed do not have the employee meal flat rate: they can deduct actual meals on trips (within reasonable limits, typically max CHF 15–20/meal documented).
100 meals × CHF 18 = CHF 1,800 deductible if justified.
Receipt + note «trip client X, date». Exclude meals with friends or family.
Digital, software and training
The most underestimated recurring expense: CHF 10/month subscriptions that add up to hundreds by year-end.
7. Software, SaaS, licences (Adobe, Microsoft, CRM, accounting)
Paid with private card or personal Apple ID. Never appear in the income statement.
CHF 1,200/year subscriptions = ~CHF 360 tax saved.
Business account or annual card export. «IT expenses» category in chart of accounts.
8. Hosting, domains, professional email, cloud
Considered «too small» to record individually.
CHF 200–600/year cumulative.
One aggregated line at year-end with attached list if needed.
9. Courses, certifications, professional conferences
Paid privately as «personal investment». If linked to current activity, deductible (max CHF 12,900 federal training deduction; self-employed: expense in income statement).
Course CHF 2,500 → ~CHF 750 saved at 30% rate.
Course invoice + programme showing link to activity. Exclude unrelated generic MBAs.
10. Books, journals and specialist subscriptions
Amazon, Kindle, trade subscriptions: never tracked.
CHF 150–400/year.
Record under «training/documentation expenses» with proof of purchase.
Insurance, pension and professional services
«Boring» items but fully deductible from business income.
11. Professional liability and legal protection
Premiums paid as «personal»; they are operating expenses for doctors, architects, consultants, IT.
CHF 800–2,000/year premium → CHF 240–600 saved.
Policy in business name or note covering professional activity only.
12. Association fees (Chamber of Commerce, sector bodies)
Chamber, professional societies: 100% deductible as professional representation.
CHF 200–800/year.
Association invoice in accounts, «administrative expenses» category.
13. Fiduciary, auditor, tax adviser fees
Some pay the fiduciary privately for «simplicity». Fully professional expense.
CHF 1,500–3,000 fees → CHF 450–900 saved.
Invoice to sole proprietorship; payment from business account.
14. Business bank account fees
Account, transfer, card fees: fully deductible on dedicated business account.
CHF 200–500/year.
Annual export of bank costs; never deduct fees on mixed private account.
Other forgotten items: marketing and receivables
Less frequent but costly when applicable.
15. Online advertising and marketing tools
Google Ads, Meta, LinkedIn Premium business: paid with private card.
CHF 500–3,000/year for active client acquisition.
Platform invoices + screenshots of campaigns linked to activity.
16. Bad debts (write-down)
Unpaid issued invoices stay in revenue. If definitively lost, can be written down with documentation (reminders, client insolvency).
CHF 5,000 uncollected invoice = CHF 5,000 less taxable profit.
Internal reminder procedure → write-down decision → accounting entry.
17. Start-up costs (first years)
Costs before office opening or first revenue: advice, logo, website, registration. Deductible when activity actually started.
Variable; can be CHF 2,000–10,000 in year one.
List pre-opening expenses with dates; include in start-up year.
Pre-filing checklist: 10 questions
Before signing your return, confirm you can answer yes where applicable:
- Have I calculated professional share of rent and utilities if I work from home?
- Do I have a mileage log or documentation of professional car costs?
- Are phone, internet and cloud split with documented %?
- Are all software subscriptions in the income statement?
- Are this year's courses and conferences recorded with invoices?
- Are professional liability and association fees included?
- Are fiduciary fees and business bank costs deducted?
- Are PC, phone and furniture correctly depreciated?
- Have I checked bad debts to write down?
- Does every item have supporting documents kept for 10 years?
7 tips to stop gifting the tax authority
- Record every expense within 48 hours: year-end memory fails, software does not
- Use a business account: automatically separates professional from private
- Create chart of accounts categories for «forgotten» items (km, home office, SaaS)
- In November, export all card transactions and compare with accounts
- Ask your fiduciary: «What deductions did I miss last year?» — that is their job
- Do not deduct holidays, hobbies or private equipment: an audit costs more than illegal savings
- AccountEX suggests categories and recurring items based on your activity type
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