Fixed-term contracts (befristete Arbeitsverträge) look like a hard stop: the date arrives, the job ends, no dismissal needed. In reality, German fixed-term law under the TzBfG is a minefield — for the employer. A remarkably high share of fixed terms are legally defective, and a defective term does not shorten the contract: it converts it into a permanent one. Late signatures, botched „extensions”, forbidden prior employment and abusive contract chains are the classic failure modes. The catch: the challenge — the Entfristungsklage — must be filed within three weeks of the agreed end date, and almost nobody knows that clock exists.
The two tracks: with and without a justifying reason
Track 1: sachgrundlose Befristung — the two-year rule
Without any justifying reason, a fixed term is permitted for a maximum of two years, within which the contract may be extended at most three times (§ 14 (2) TzBfG). Typical pattern: 12 months + 6 + 6. Every element is strict: a fourth extension, a day beyond two years, or any defect in an extension makes the term invalid — and the contract permanent (§ 16 TzBfG).
Track 2: Befristung mit Sachgrund — the reason catalogue
With a justifying reason under § 14 (1) TzBfG, longer and repeated fixed terms are possible. The main catalogue grounds:
- Temporary operational need — a genuinely time-limited spike, not ordinary fluctuation,
- cover for an absent employee (Vertretung) — maternity, parental leave, long illness; the workhorse of the catalogue,
- nature of the work — projects, seasonal work, certain artistic and academic roles,
- probationary fixed term, budget-funded positions (mainly public sector), the employee’s own wish, and court-settlement fixed terms.
Each ground has case-law tripwires: a „project” that is actually the company’s permanent business does not qualify; a Vertretung term must trace to an identifiable absent employee. Mechanically recycled grounds are attackable.
The Vorbeschäftigungsverbot: no prior employment — ever, almost
A sachgrundlose fixed term is prohibited if you were previously employed by the same employer (§ 14 (2) sentence 2 TzBfG). For years the BAG read „previously” as „within the last three years” — until the Federal Constitutional Court struck that reading down in 2018. Since then the ban is essentially unlimited in time, with narrow exceptions where insisting on it would be unreasonable: prior employment that lies very long ago (the BAG accepted 22 years; it rejected 8 years), was of an entirely different nature, or was very short. Practical upshot:
- A working-student job, internship-as-employment or earlier stint at the same legal entity can invalidate a later sachgrundlose term — instant permanent contract.
- „Same employer” means the same legal entity; a different group company is formally a different employer, though abusive constructions designed purely to dodge the ban can fail.
Written form before day one (§ 14 (4) TzBfG)
The fixed-term clause must be agreed in written form — wet-ink signatures of both parties, or since the 2025 form-relaxations a qualified electronic signature — before you start working. This is where an astonishing number of terms die:
- Oral agreement, paperwork later: start on Monday, sign on Wednesday — the term is void and the contract that arose on Monday is permanent. The late signature does not cure it.
- Scan/PDF signatures: a simple scanned or DocuSign-style signature generally does not satisfy the strict form requirement.
- Only one party signed, or signatures on documents that don’t form one deed: defective.
The extension trap: „Verlängerung” vs. new contract
Within the two-year track, an extension is only a valid „Verlängerung” if it (1) is signed before the current term expires and (2) changes nothing except the end date. Any other change agreed on the occasion of the extension — a salary increase, more hours, a new job title — legally makes it a new fixed-term contract. And a new sachgrundlose contract is barred by the prior-employment rule (you now have prior employment with this employer), so the term is invalid and the contract permanent. The same happens when the „extension” is signed after the old term already expired, even by a few days.
Important nuance: improving your terms in a separate agreement during the running term is fine — the poison is bundling changes into the extension deed itself. Employers mix this up constantly.
Chain fixed terms (Kettenbefristung)
With ever-fresh Sachgründe — usually Vertretung — employers can string together many consecutive terms. Following the ECJ (Kücük) and the BAG, courts review long chains for abuse of rights: as rough orientation, more than eight years or twelve extensions triggers closer scrutiny; beyond ten years / fifteen extensions abuse is strongly indicated and the burden shifts to the employer. Universities, hospitals and the public sector are the classic battlegrounds.
The Entfristungsklage and its three-week deadline
The invalidity of a fixed term must be asserted by filing an Entfristungsklage at the labor court within three weeks of the agreed end date (§ 17 TzBfG) — the same mechanism as the three-week deadline for dismissals. Miss it, and even a blatantly void term is deemed valid. Key mechanics:
- You can file before the end date, as soon as the dispute is foreseeable — no need to wait.
- Signing extension after extension does not waive your arguments; the courts review the last term (and, on abuse, the chain).
- Simply working on after the end date with the employer’s knowledge can continue the relationship indefinitely (§ 15 TzBfG) — but never rely on this; file.
- If the employer instead ends the contract early by dismissal, that is a normal dismissal case — a Kündigungsschutzklage; ordinary early termination is only possible if the contract or a collective agreement provides for it (§ 15 (4) TzBfG).
For non-EU employees, a successful Entfristung also stabilizes residence status — a permanent contract instead of an expiring one changes the conversation with the Ausländerbehörde entirely (see residence permit after job loss).
Worked example
Aisha, a UX designer in Berlin, gross €4,800 per month, joined on a 12-month sachgrundlose fixed term, extended twice. The second extension deed also raised her salary from €4,500 to €4,800 „in recognition of performance.” When the employer announces the contract will „simply end,” we review the file:
- The bundled raise means the second „extension” was legally a new fixed-term contract;
- as a new sachgrundlose term with prior employment at the same employer, it is invalid (§ 14 (2) TzBfG);
- result: the contract is permanent — if asserted in time.
We file the Entfristungsklage two weeks before the end date. At the Gütetermin the employer — facing an employee it must otherwise keep indefinitely — offers a choice: continued permanent employment, or severance. Aisha, who has another offer, takes €19,200 (four monthly salaries — far above the 0.5-per-year convention for two years of service, because the employer’s litigation risk was near-total), plus salary through a three-month wind-down and a Grade-2 reference. Had she let the three weeks lapse, her legally permanent contract would have ended with zero.
Frequently asked questions
Does my fixed-term contract need a reason to be stated?
A sachgrundlose term needs no reason at all (within two years / three extensions). A Sachgrund term does not have to name the reason in the contract in most cases — but the reason must objectively have existed when the term was agreed, and in court the employer must prove it. Vertretung terms in particular are checked against the concrete absent employee.
Can my employer dismiss me before the fixed term ends?
Ordinary (with-notice) termination during a fixed term is only possible if the contract or an applicable collective agreement expressly allows it (§ 15 (4) TzBfG); extraordinary termination for grave cause is always possible in theory but rarely holds. If you receive notice mid-term, both the dismissal and — later — the term itself can be attacked; the deadlines run separately.
I’ve signed five contract extensions. Have I accepted the fixed terms?
No. Signing extensions does not forfeit your right to challenge. The court examines the validity of the most recent term, and long chains additionally face the abuse review. What does forfeit your rights is missing the three-week window after the final agreed end date.
Does the two-year rule apply in startups or to older employees?
Two statutory variants exist: newly founded companies may use sachgrundlose terms for up to four years in their first four years (§ 14 (2a) TzBfG), and for employees aged 52+ coming out of longer unemployment, terms up to five years are possible (§ 14 (3) TzBfG). Both have strict conditions that fail frequently.
What happens to my visa if the fixed term ends?
An expiring contract is not a dismissal, so no dismissal protection applies to the mere expiry — which makes the Entfristung check the more important. A defective term means a permanent contract: the strongest possible position for any residence-permit renewal. Have the contract reviewed months before the end date, not in the final week.
Pregnancy, works council membership — do special protections stop the term from ending?
Generally no: special dismissal protection guards against dismissals, and a fixed term ends without one. Narrow exceptions and discrimination arguments exist — refusing an otherwise-routine extension because of pregnancy can be unlawful discrimination. Very fact-sensitive; take advice early.