
Sàrl incorporation for engineering firms in Erlinsbach (AG) explained simply
Swiss accounting law (art. 957 ff. of the Code of Obligations) sets a precise frame, yet day-to-day practice often stays fuzzy. This guide walks through what actually matters for a business based in Erlinsbach (AG).
Choosing the structure: Sàrl, SA or sole proprietorship
Check the company name before any enthusiasm: availability in the commercial register, internet domain, possible trademark. Renaming later costs time and trust, in Erlinsbach (AG) as elsewhere.
On the Sàrl incorporation side, the first financial year may be longer or shorter than a calendar year: choosing the first closing date wisely avoids a pointless mini-closing.
Swiss VAT: rates, threshold and filings
Registration happens with the Federal Tax Administration and yields a VAT number based on the business identifier (format CHE-xxx.xxx.xxx VAT). From then on, every invoice must state that number, the rate applied and the tax amount — three details Sàrl incorporation should lock down from day one to avoid retroactive fixes.
Returns are filed quarterly (effective method) or twice a year (net tax rate method). Either way the rule is identical: file and pay within 60 days after the end of the period. An annual reconciliation with the accounts is required — this is where sloppy data entry gets expensive.
Salaries and social contributions: the rates to know
The salary certificate is an official tax document: it feeds the employee's tax return and serves as the reference in AHV and tax audits. Issued once a year, it must match payroll accounting and the declaration to the compensation office to the centime.
For Sàrl incorporation, the gap between agreed gross and paid net surprises every new employer: simulate it BEFORE hiring to avoid misunderstandings with the future employee.

Digitalising Sàrl incorporation: what actually works
The classic digitalisation traps are avoidable: scanning without quality control (unreadable records), stacking disconnected tools (double entry in disguise), or neglecting access rights. One single flow from document to entry, with clear roles, beats five shiny apps.
The winning pair for Sàrl incorporation: a single inbox (e-mail, scan, photo) and one simple rule — no document sits more than a few days without a proposed entry.
Erlinsbach (AG): what changes, what does not
Working with a fiduciary from Erlinsbach (AG) no longer depends on geography: the documents of a business in Erlinsbach (AG) are shared online, while the canton Aargau keeps its own deadlines for the tax return.
Federal deadlines do not move in Erlinsbach (AG): VAT within 60 days, salary declaration in January, 10-year record retention — postal code 5017 changes nothing about those rules, only the sender's address.
Frequently asked questions
What are the legal obligations for Sàrl incorporation in Switzerland?
The foundation is the Code of Obligations: proper bookkeeping (art. 957a CO), annual accounts (balance sheet, income statement, notes) and 10-year retention of books and records (art. 958f CO). VAT applies from CHF 100,000 of turnover, and social insurance settlements from the first employee. Nothing is different in Erlinsbach (AG): federal law applies.
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 Erlinsbach (AG), family allowances follow the canton's rates.
How much does Sàrl incorporation cost in Erlinsbach (AG)?
It depends on document volume, the number of salaries and VAT complexity — no serious figure can be quoted without examining the file. Two levers cut the bill everywhere: digitised, well-filed receipts and software that prepares entries instead of having them re-keyed.
How long must records related to Sàrl incorporation be kept?
Ten years from the end of the financial year concerned (art. 958f CO). Electronic retention is permitted if the integrity and readability of the records are guaranteed — a serious digital archive validly replaces paper binders. A business in Erlinsbach (AG) can therefore archive fully digitally.
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