
Accounting digitalisation in Cossonay: rules, deadlines, best practice
Whether you run a Sàrl, an SA or a sole proprietorship in Cossonay, accounting eventually lands on your desk. Here are the practical reference points — legal basis, deadlines and common pitfalls — to decide with a clear head.
The Swiss legal frame for accounting
A small business does not mean small obligations: from the first salary or the first VAT return, mistakes get expensive — in Cossonay as anywhere.
The good news: the Swiss frame is stable and predictable. Structure accounting once — chart of accounts, document flow, calendar — and the same organisation pays off for years.
Digitalising accounting: what actually works
Automation is judged on the exceptions: what happens when the document is unreadable, the supplier unknown, the amount divergent? A good tool isolates those cases and lets a human decide fast — precious for teams in Cossonay.
For an SME in Cossonay, the real gain of digitalised accounting shows day to day: no paper pile at month-end, VAT prepared continuously, and an owner reading today's figures rather than last quarter's.
A Swiss SME's accounting calendar
January: salary declaration to the compensation office and salary certificates. End of February, May, August, November: quarterly VAT returns (effective method), each to be filed and paid within 60 days after the quarter ends. Within six months of year-end: approved annual accounts. Then: the tax return under cantonal deadlines, with extensions possible.
For accounting, year-end is prepared in October: last invoices, investment decisions, provisions to assess — December is too late to act, January is for recording.

A well-structured SME chart of accounts
Shareholder current accounts demand strict hygiene: every private withdrawal documented, interest at the rates accepted by the tax administration, and a clean-up at closing.
Standard numbering also enables automation: stable posting rules (same supplier, same account) make data entry predictable and the audit faster. Avoid changing the chart of accounts mid-year — migrate at the closing date, with a documented mapping table.
Cossonay: what changes, what does not
Working with a fiduciary from Cossonay no longer depends on geography: the documents of a business in Cossonay are shared online, while the canton Vaud keeps its own deadlines for the tax return.
For a business in Cossonay, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Vaud.
Frequently asked questions
Do you need a fiduciary for accounting, or can you do it yourself?
Both are defensible. Below CHF 500,000 of revenue, a sole proprietorship may keep simplified accounts itself. As soon as payroll, VAT and a closing with tax stakes are involved, professional support prevents mistakes that cost more than the fees. With a shared platform, the fiduciary does not even need to be in Cossonay.
Does MyFiducia.ai work for a business based in Cossonay?
Yes: the platform runs online, the rules applied are federal (VAT, CO, AHV), and the file can be shared with any fiduciary. A business in Cossonay manages its documents, VAT and exports exactly as anywhere in Switzerland.
What is simplified bookkeeping and who can use it?
Sole proprietorships and partnerships under CHF 500,000 of revenue may limit themselves to recording income, expenses and assets (art. 957 para. 2 CO). Once over the threshold — or upon founding a Sàrl or an SA — full accounts with balance sheet, income statement and notes become mandatory. The CHF 500,000 threshold is assessed the same way in Cossonay.
Which social contributions does a Swiss employer pay?
AHV/IV/APG: 5.3% employer share (the same is withheld from the employee); unemployment insurance: 1.1% each up to CHF 148,200 a year; occupational pension (LPP) by age and plan (employer at least 50%); occupational accident insurance paid by the employer; family allowances by canton. For an employer in Cossonay, family allowances follow the canton's rates.
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Switch to accounting that keeps itself up to date
MyFiducia.ai automates accounting for businesses in Cossonay: AI-read documents, posting suggestions, VAT and exports ready for your fiduciary. Try the platform or browse our other guides.
The application is operated in French.