If you have worked for your employer for more than six months and the company employs more than 15 people, you have a statutory right to reduce your working hours — and if the employer does not refuse in the correct form and by the statutory deadline, your request is deemed granted by operation of law. The claim under § 8 TzBfG is one of the most underused employee rights in Germany — many international employees assume part-time is a favour the employer can decline at will. It is not. The employer can only refuse for genuine operational reasons, must do so in written form, and must do so at least one month before your requested start date — miss any of these, and your part-time arrangement takes effect exactly as you requested it.
Who is entitled: the two thresholds
§ 8 TzBfG sets two conditions, both easy to check:
- Six months of tenure. Your employment relationship must have existed for more than six months at the requested start of the reduction (§ 8(1) TzBfG). Probation time counts toward the six months.
- More than 15 employees. The employer must regularly employ more than 15 employees, excluding trainees (§ 8(7) TzBfG). The count is per head, not full-time equivalent, and applies to the company (Unternehmen) as a whole — a five-person Berlin office of a 200-employee company clears the threshold.
No reason is required — childcare, study, a side business or simply more free time: the motive is legally irrelevant, and the employer has no right to ask.
How to apply: form, deadline, content
The request must be made in text form (Textform) at least three months before the desired start date (§ 8(2) TzBfG). Email suffices; a purely verbal request does not trigger the statutory machinery. The request should state:
- the extent of the reduction (e.g., from 40 to 30 hours per week), and
- ideally the desired distribution of the reduced hours (e.g., Monday to Thursday, 8:00–16:00).
Stating the distribution is tactically important: the fiction of consent described below covers the distribution as well. Applying less than three months ahead is not fatal — case law treats it as a request for the earliest permissible date.
The employer must then discuss the change with you with the aim of reaching agreement (§ 8(3) TzBfG); in practice this consultation is often skipped — which does not help the employer.
When the employer may refuse: betriebliche Gründe
The employer may reject the request only where operational reasons (betriebliche Gründe) conflict with it (§ 8(4) TzBfG). The statute mentions substantial impairment of organisation, workflow or safety, and disproportionate costs. On paper this is a low bar — the BAG has said the reasons need not reach the weight of dismissal-justifying grounds. In practice, the case law makes refusals hard to defend, because the courts apply a three-stage test:
The three-stage test
- Organisational concept. The employer must show an actual organisational concept that determines the working-time arrangement — not a preference, but a documented decision (e.g., „every consultant must be available five days a week for client continuity”).
- Genuine conflict. The concept must actually conflict with your requested hours. If tasks can be redistributed, a job-share partner hired, or coverage reorganised, there is no conflict.
- Sufficient weight. The operational reasons must carry real weight — a substantial impairment, not mere inconvenience or modest extra cost.
Generic assertions — „we need you full-time”, „the team is stretched”, „we have always worked this way” — fail this test. In our practice, the majority of refusals we review are not defensible in court.
The fiction of consent: the employer’s deadline trap
This is the sharpest tool in § 8 TzBfG. The employer must communicate its decision in written form (Schriftform — a signed original, not an email) at least one month before your requested start date (§ 8(5) TzBfG). If the employer fails to reject in that form and by that deadline, the law deems your consent granted: your working time is reduced exactly as requested, and the distribution you proposed is deemed fixed as well.
Distribution of hours
The right covers not just the volume but the placement of your hours. If the employer validly refuses your proposed distribution but not the reduction, the reduction stands and the distribution is negotiated. Once a distribution is fixed, the employer may change it later only with one month’s notice and only if the operational interest substantially outweighs yours (§ 8(5) TzBfG) — a high bar where childcare arrangements depend on the schedule.
Getting back to full-time: § 9 TzBfG
Understand this before you apply: § 8 TzBfG is a one-way street. There is no statutory right to return to your previous hours. What you have instead is § 9 TzBfG: a part-time employee who has notified the employer of the wish to extend hours must be given preferential consideration when a suitable vacancy is filled — unless urgent operational reasons or the working-time wishes of other part-timers conflict. That is a priority claim to vacancies, not a return ticket. If you may want your hours back, Brückenteilzeit under § 9a TzBfG (companies with more than 45 employees) gives you a fixed part-time period of one to five years with an automatic return — usually the better instrument for a life phase.
The discrimination ban: § 4 TzBfG
Part-time employees may not be treated worse than comparable full-timers unless objective reasons justify it (§ 4(1) TzBfG). Pay and all divisible benefits must be granted pro rata temporis: salary, bonus, vacation entitlement, company pension contributions, stock awards, JobRad, everything. Watch two classic violations:
- Bonus and promotion penalties. „Part-timers are not bonus-eligible” or systematic exclusion from promotion tracks violates § 4 TzBfG.
- Overtime premiums. Clauses granting premiums only for hours beyond the full-time threshold disadvantage part-timers; ECJ and BAG case law requires measuring against your individual part-time hours for premium entitlements. If you work beyond your contract, read our guide to overtime pay.
Retaliation for asserting the right — worse shifts, exclusion from projects, a sudden negative review — is prohibited (§ 5 TzBfG, § 612a BGB). See our article on retaliation (Maßregelung).
Tactical notes from practice
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Apply in text form, keep proof
Send the request by email with read confirmation or hand it over against acknowledgement. State volume, start date and desired distribution precisely — the fiction of consent adopts your exact wording.
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Calendar the one-month deadline
Note the date one month before your requested start. If no signed written refusal has reached you by then, the reduction is deemed granted — do not let the employer „negotiate” past it.
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Attend the consultation, concede nothing
Discuss in good faith, but do not withdraw or „pause” your request verbally. A withdrawal kills the fiction.
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After a valid refusal: two-year block
A new reduction request is possible at the earliest two years after a justified refusal or an agreed reduction (§ 8(6) TzBfG) — so get the first application right.
Worked example
A data analyst in Düsseldorf, employed 3 years at a 90-employee company, earns €5,600 gross on a 40-hour week. She requests, by email 14 weeks ahead, a reduction to 32 hours from 1 March, distributed Monday–Thursday. Pro-rata salary: €5,600 × 32/40 = €4,480 gross.
The employer replies by email three weeks before the start date: „We cannot approve this for staffing reasons.” Two fatal defects: the refusal is out of time (less than one month before the start) and not in written form. The fiction of § 8(5) TzBfG applies — from 1 March her contract is 32 hours, Monday–Thursday, at €4,480. When the employer nevertheless schedules her for Fridays, we assert the deemed contract change; the employer concedes within a week. Vacation converts to 24 days (30 × 4/5), pension contributions continue pro rata, and her bonus is paid at 80% of target — all § 4 TzBfG compliant.
Frequently asked questions
Do I have to give a reason for wanting part-time?
No. The right under § 8 TzBfG is unconditional — no childcare, care or health justification is required, and the employer may not make approval contingent on the reason.
How do I know if the 15-employee threshold is met?
Count heads across the whole legal entity, excluding trainees. Part-timers count as full heads — different from the KSchG threshold, where hours are weighted.
Can my employer refuse because my role is „too senior” for part-time?
There is no seniority exception. Managers, team leads and specialists all hold the claim. The employer would have to prove, under the three-stage test, that a documented organisational concept genuinely requires full-time presence in your specific role — courts are sceptical.
Will part-time reduce my dismissal protection or severance?
Protection under the KSchG is unaffected. But severance is normally calculated on your current monthly salary — reducing hours shortly before a restructuring can shrink a later package. If redundancies are foreseeable, weigh the timing; our guide to severance calculation explains the mechanics.
Can I combine reduced hours with remote work?
§ 8 TzBfG covers volume and distribution of time, not place of work. A home-office arrangement is a separate negotiation — see home-office rights in Germany — but the two requests are often bundled successfully in practice.