
Everything that matters about Sàrl incorporation for dental practices in Killwangen
Between VAT, social contributions and the year-end close, a Swiss SME juggles dozens of deadlines a year. This page focuses on Sàrl incorporation in Killwangen: what the law requires, what can be automated, and when to delegate.
Choosing the structure: Sàrl, SA or sole proprietorship
Settling in Killwangen does not change federal law, but the canton shapes what follows: profit and capital tax rates, family allowances, possible start-up support. Comparing seriously before fixing the seat can pay off — moving a company later costs more.
From day one, three administrative tracks open: affiliation to an AHV compensation office, review of VAT liability (CHF 100,000 threshold) and setting up the accounts. Handling Sàrl incorporation from the first month costs far less than reconstructing a whole year in December.
Salaries and social contributions: the rates to know
Every salary paid in Switzerland triggers joint contributions: AHV/IV/APG at 10.6% in total, i.e. 5.3% borne by the employer and 5.3% withheld from the employee; unemployment insurance at 2.2% (1.1% each) up to CHF 148,200 of annual salary. Add occupational pension (LPP credits of 7 to 18% of the coordinated salary depending on age, employer at least 50%), accident insurance (occupational accidents paid by the employer) and family allowances.
For Sàrl incorporation, the monthly payslip is only the visible part: instalments to the funds, annual settlements and certificates form the real cycle, January to January.
The Swiss legal frame for Sàrl incorporation
For an owner in Killwangen, the question is never “do we need accounts?” but “at what level of detail?”. The CO sets the floor; the bank, the tax office and the shareholders set the rest.
Art. 957a CO requires complete, truthful and systematic recording of transactions, each entry backed by a supporting document. For Sàrl incorporation, that means in practice: no movement without a receipt, and an audit trail that can be reconstructed at any time — including during a VAT or AHV inspection.

Swiss VAT: rates, threshold and filings
A VAT return is prepared, not endured: clean VAT accounts, one code per rate and a monthly variance check make the deadline trivial — for registered businesses in Killwangen too.
The right reflex for Sàrl incorporation: file every supplier invoice with its VAT on receipt. Forgotten input VAT is money definitively lost once the limitation period runs out.
Killwangen: what changes, what does not
Sole proprietorship, Sàrl or SA in Killwangen: the AHV contact remains the competent compensation office, and taxes follow the scales of the canton Aargau.
For a business in Killwangen, that means VAT returns identical to anywhere in Switzerland, but a tax return and family allowances governed by the canton Aargau.
Frequently asked questions
Do you need a fiduciary for Sàrl incorporation, 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 Killwangen.
Which documents should be prepared for the year-end closing?
Bank and cash statements at the closing date, the inventory of stock and work in progress, final AHV/LPP/accident settlements, contracts signed or amended during the year, invoices straddling two years and the detail of accruals. With an up-to-date document archive, most of it is already there. The list is identical in Killwangen: the CO dictates it, not the commune.
Can Sàrl incorporation be automated with AI?
Largely, yes: automatic document reading, posting suggestions, bank reconciliation via QR references and VAT exports. Human approval remains essential — AI prepares, the professional checks. That is exactly how MyFiducia.ai approaches Sàrl incorporation.
When must a business register for VAT?
As soon as its worldwide annual turnover reaches CHF 100,000 (CHF 250,000 for non-profit sports or cultural associations). Below that, voluntary registration remains possible and often makes sense to reclaim input VAT on investments. The threshold is federal: it applies in Killwangen as everywhere in Switzerland.
Also worth reading
In neighbouring municipalities
Switch to accounting that keeps itself up to date
MyFiducia.ai automates Sàrl incorporation for businesses in Killwangen: 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.