Werkvertrag — Work-for-Results Contract under § 631 BGB

The Werkvertrag — the German work-for-results contract — is the contractual home for any obligation to produce a defined, warranted Werk. It is the typical instrument for fixed-scope software builds, construction and renovation works, architect and engineering services, machine fabrication, equipment installation, video production, translation deliverables and a long list of other engagements where the customer pays for an outcome rather than for time spent. Drafting it well requires care on two axes that do most of the work in litigation: the Werkvertrag-versus-Dienstvertrag distinction at § 631 BGB and § 611 BGB, and the Abnahme-and-Mängelhaftung mechanics at §§ 640, 641, 644 and 634a BGB. Both axes routinely surface as arguments in disputes. This page is the drafting reference for the contract type. See also /handbook/de/contracts/dienstvertrag.html, /handbook/de/form-requirements.html, /handbook/de/agb-rules.html, /handbook/de/standard-clauses.html, and /docs/eu/germany.html.

Applicable Law

The civil-law foundation is § 631 BGB: one party — the Unternehmer — owes the production of the agreed Werk, and the other party — the Besteller — owes the agreed Vergütung. Paragraph 2 makes the type broad: a Werk can be the production or alteration of a tangible item or any other result achieved through work or service. The defining structural feature is exactly what distinguishes the Werkvertrag from the § 611 BGB Dienstvertrag: the Unternehmer warrants an Erfolg — a result. If the result is missing or defective, the Mängelhaftung regime under §§ 633 ff. BGB engages and the customer is not obliged to pay full price even if the contractor worked diligently. Cross-link to /handbook/de/contracts/dienstvertrag.html and /docs/eu/germany.html.

The BGB recognises several specialised Werkvertrag subtypes whose rules layer on top of the general regime. The Bauvertrag at § 650a BGB covers contracts for the construction, restoration, demolition or alteration of a building or an outdoor facility of substantial significance, and pulls in the Verbraucherbauvertrag form rule at § 650i BGB where the customer is a consumer. The Architekten- und Ingenieurvertrag at § 650p BGB covers planning and supervisory services for building works and brings its own Zielfindungsphase rules. Commercial practice further distinguishes the Pauschalpreisvertrag (fixed price for the entire Werk), the Stundenvertrag (time-and-materials with capped or open hours), the Einheitspreisvertrag (unit prices applied to measured quantities, classic in construction) and the Selbstkostenvertrag (cost-plus). The pricing mode interacts with risk allocation under § 644 BGB, the Abnahme mechanics under § 640 BGB, and the change-order discipline; the drafting should pick one consciously rather than slide between modes implicitly. Software-development engagements often present as mixed typengemischte Verträge where the build phase is Werkvertrag (fixed deliverable) and a subsequent support phase is Dienstvertrag (ongoing service); each phase is governed by its own regime, and the contract should allocate work-packages explicitly to each.

Form Requirements

There is no statutory form for a general Werkvertrag. The default under § 631 BGB is Formfreiheit — a binding contract can arise from oral agreement or even from conclusive conduct. Textform under § 126b BGB — a plain email exchange that records the parties’ identities, the Werkbeschreibung and the Vergütung — is sufficient between the parties as a matter of contract formation and is sufficient evidentiarily in most disputes. For higher-value B2B engagements, Schriftform under § 126 BGB (handwritten signature) or Elektronische Form under § 126a BGB (qualified electronic signature) is recommended for higher evidentiary weight: a QES carries the Anscheinsbeweis of authenticity per § 371a ZPO and survives forensic challenge better than an unqualified electronic signature. One important carve-out: the Verbraucherbauvertrag under § 650i BGB — a contract obliging the contractor to build a new building or to carry out substantial conversion measures for a consumer — must be concluded in Textform; conclusion in mere oral or conclusive form leaves the contractor without an enforceable Vergütungsanspruch and the consumer with a fourteen-day right of withdrawal once the building description has been provided. Cross-link to /handbook/de/form-requirements.html.

Required Clauses

A Werkvertrag capable of supporting a Vergütungsanspruch under § 631 BGB and a Mängelhaftungsanspruch under §§ 633 ff. BGB needs four recurring clauses.

Vertragsparteien. Full legal names, Sitz, and where applicable the Handelsregisternummer and registry court of each party. Einzelkaufleute identify with their full name plus e.K. designation. § 305 BGB requires identifiability; vague references to “the parties” defeat later enforcement.

Werkbeschreibung. The central clause and the one that does the most work in the Mängelhaftung analysis. The Werk must be defined precisely enough that any later deviation can be measured against it: technical specifications, functional requirements, applicable industry standards (DIN, ISO, VOB/C as relevant), referenced design documents, anticipated environmental and operating conditions. Without an enforceable Werkbeschreibung the Mängelbegriff under § 633 BGB collapses into a vague übliche Beschaffenheit test that is hard to litigate either way. For software projects, the Werkbeschreibung typically consists of a signed specification document referenced into the contract; for construction, the Leistungsverzeichnis with its Einheitspreise serves the same role. The clause must also avoid language characteristic of a Dienstvertrag — “Beratung und Begleitung”, “fachliche Unterstützung”, “agile Mitarbeit” without defined deliverables — unless the parties intentionally classify the work-package as Dienstvertrag and accept its consequences.

Abnahmekriterien. The criteria under which the Werk counts as accepted (see Abnahme below). The clause should specify the acceptance test, the documentary form of the Abnahmeprotokoll, the Frist within which acceptance must be declared after readiness has been notified, and the handling of unwesentliche Mängel (which do not bar acceptance but trigger a defect list). Without express Abnahmekriterien the parties default to the statutory regime at § 640 BGB and frequently disagree on what counts as “abnahmereif”.

Vergütung. The pricing structure: Pauschalpreis, Stundenvertrag, Einheitspreisvertrag, Selbstkostenvertrag, or hybrid. Specify the basis (deliverable submission, measured quantities, time records, fixed cadence), the cycle, the VAT treatment and the payment terms. Abschlagszahlungen on partial completion can be agreed under § 632a BGB; a Sicherheitseinbehalt of typically five to ten percent until Mängelbeseitigung is industry-customary in construction. § 631 BGB itself requires only that Vergütung be agreed; § 632 BGB supplies a fall-back to customary remuneration where compensation has been promised but no rate is fixed.

The JSON required_clauses array enumerates these four for AI-agent consumption and downstream tooling.

Optional and Recommended Clauses

Beyond the required four, several clauses are not statutorily mandatory but are commercially essential.

Liefertermine und Meilensteine. Fixed delivery dates, intermediate milestones with partial-acceptance windows, and the consequences of slippage. Where time is of the essence under § 323 BGB, the clause should say so expressly; otherwise the customer must set a Nachfrist before terminating for delay.

Abnahmeverfahren. A separate clause for the formal Abnahme mechanics: notification of readiness, test windows, escalation procedure on disputed Mängel, Teilabnahme rules for milestone deliveries, and the explicit Abnahmeprotokoll template. Cross-link to Abnahme below.

Mängelhaftungsfrist. The contractual Verjährungsfrist for Mängelansprüche, calibrated to the statutory floor at § 634a BGB: two years for a Werk whose Erfolg consists of the manufacture, maintenance or alteration of a thing or in services rendered relating thereto, two years for services concerning a building (planning, supervision) where the result has no direct relationship to the structure, and five years for a Werk consisting of the construction of a building and for planning and supervisory services whose result relates directly to the structure. Departures from the statutory floor are heavily constrained in AGB (see below).

Änderungsverfahren / Change-Request-Procedure. Software and complex industrial projects almost always require scope-change discipline: a written change request, an impact assessment from the Unternehmer on price and timeline, and a signed change order before the change becomes binding. Without this discipline, scope creep produces fee disputes that turn on conflicting Nebenabreden evidence.

Vertragsstrafe. A pönale for missed delivery dates or breach of confidentiality. The clause must respect three guardrails: in B2B AGB the BGH treats a Vertragsstrafe above five percent of the order value as a candidate for invalidity, with BGH VII ZR 198/14 often cited; Verbraucher-AGB cannot impose a Vertragsstrafe in the cases listed at § 309 Nr. 6 BGB at all; and a court can reduce a disproportionately high Vertragsstrafe under § 343 BGB on application by the obligor (in B2B individual contracts) but not in Handelsgeschäfte where § 348 HGB excludes the reduction power.

Versicherungspflichten. Professional indemnity and property-damage liability insurance for the contractor at agreed minimum cover levels. Construction and engineering contracts also typically require Bauleistungsversicherung and Bauwesenversicherung during the build phase.

Urheberrechtsabtretung. Critical for any engagement producing copyrightable output — software, design, written work product. Under § 31 UrhG, copyright stays with the author absent an express grant of Nutzungsrechte; the clause should grant the client an exclusive, transferable, sub-licensable right to use the work product for all known and currently unknown forms of exploitation.

Prohibited Clauses (in AGB Context)

Where the Werkvertrag is concluded as AGB — pre-formulated, intended for multiple use and unilaterally imposed — three patterns are routinely struck down.

Verkürzung der Mängelhaftungsfrist unter den gesetzlichen Mindestwert. § 309 Nr. 8 lit. b ff BGB flatly voids any AGB clause in Verbraucherverträgen that shortens the Verjährung der Mängelansprüche below the statutory floors of § 634a BGB. For new-construction works the floor is five years; for movable goods and services it is two years. The rule is ohne Wertungsmöglichkeit — no fact-pattern justification is available. In B2B AGB § 309 Nr. 8 does not apply directly, but the BGH applies it through § 307 BGB Indizwirkung: an AGB reduction of warranty for new construction to anything below five years is unreasonably disadvantageous and falls. A clause reducing warranty for movable goods or services from two years to one year is more defensible in B2B AGB but still attracts BGH scrutiny, and shorter than one year is regularly struck down.

Haftungsausschluss bei grober Fahrlässigkeit oder Vorsatz. § 309 Nr. 7 BGB flatly voids any AGB clause that excludes or limits liability (a) for damage from injury to life, body or health caused by negligent breach of duty by the user or by intentional or negligent breach of duty by a legal representative or vicarious agent, or (b) for other damage caused by gross-negligence breach of duty by the user or by intentional or grossly-negligent breach of duty by a legal representative or vicarious agent. The rule reaches Werkverträge fully. In B2B AGB, § 309 Nr. 7 does not apply directly, but the BGH applies it through § 307 BGB Indizwirkung. Liability caps for ordinary negligence are permissible in both regimes provided they leave the foreseeable typical damage covered.

Einseitige Verlagerung der Leistungsgefahr auf den Unternehmer. AGB that shift the risk of accidental performance impossibility unilaterally to the Unternehmer in cases where § 644 BGB places the risk on the Besteller (after Abnahme or after Annahmeverzug) fail under § 307 BGB. The default risk allocation reflects considered legislative judgment and any one-sided departure in AGB carries a high burden of justification. Cross-link to /handbook/de/agb-rules.html for the complete Klauselverbote catalogue.

Termination and Notice

Three regimes interlock. The Bestellerkündigung at § 648 BGB is the Werkvertrag-specific feature: the Besteller can terminate the contract at any time before completion of the Werk, with no wichtiger Grund required. The price is statutory: the Unternehmer retains the agreed Vergütung but must allow for what he saves through non-performance, what he earns or maliciously fails to earn through alternative use of his labour. The statute presumes that five percent of the Vergütung attributable to the unperformed part remains to the Unternehmer even after the saved-expenses deduction; either party may rebut this presumption with concrete evidence. The clause therefore makes a Bestellerkündigung economically expensive but legally always available.

The außerordentliche Kündigung aus wichtigem Grund at § 648a BGB is available to both parties where, on a Gesamtbetrachtung of all circumstances and weighing both parties’ interests, the terminating party cannot reasonably be expected to continue the relationship up to ordinary completion. § 648a Abs. 5 BGB then triggers a partial-acceptance and accounting obligation under § 648a Abs. 4 BGB. For Bauverträge a further specific Kündigung mechanism is provided at § 650g BGB (State of the work) and at § 650h BGB for the form requirements on construction-contract terminations, which must be in Schriftform. Standard Werkvertrag termination in non-construction contexts can be in Textform unless the contract requires more.

Abnahme

The Abnahme under § 640 BGB is the single most consequential procedural moment in a Werkvertrag. It triggers three effects that together transform the legal posture of the parties.

First, the Vergütungspflicht under § 641 BGB becomes due. Before Abnahme, the Besteller is not obliged to pay the final Vergütung (partial Abschlagszahlungen under § 632a BGB aside); after Abnahme, the full Vergütungsanspruch is fällig and ordinary default-interest rules engage.

Second, the Gefahrübergang under § 644 BGB shifts to the Besteller. Before Abnahme, the Unternehmer bears the risk of accidental destruction or deterioration of the Werk; after Abnahme, the risk lies with the Besteller, who must therefore arrange for transport, storage and insurance of the accepted Werk from that moment.

Third, the Verjährung der Mängelansprüche under § 634a BGB begins to run from the Abnahme date. The applicable period depends on the type of Werk: five years for buildings and for planning and supervisory services whose result relates directly to a building, two years for movable goods and for services in connection with a thing or building (where the result has no direct relationship to the building itself).

Forms of Abnahme recognised by the courts and the statute are three. Ausdrückliche Abnahme is the formal version: a signed Abnahmeprotokoll listing any Vorbehalte for known defects. Konkludente Abnahme arises from conduct: the Besteller takes the Werk into use without protest, or pays the final invoice, or otherwise behaves in a way that signals satisfaction. The BGH has repeatedly recognised silent acceptance where the customer continues to use the Werk without raising defect complaints for an extended period after readiness for Abnahme, even when no formal protocol was signed. Fingierte Abnahme arises under § 640 Abs. 2 BGB: if the Unternehmer has set the Besteller an appropriate deadline for Abnahme after completion and the Besteller fails within that period either to accept or to refuse acceptance with specification of at least one defect, the Werk is deemed accepted. The fiction does not apply to consumers unless the Unternehmer warned them about the consequences of inaction together with the Abnahmeaufforderung.

The clause discipline that follows from this is: define the Abnahmeverfahren expressly; choose the form of Abnahmeprotokoll; specify the Abnahmefrist; document the Vorbehalte; and ensure that the consumer-warning under § 640 Abs. 2 BGB is given in writing where the Werk is for a consumer. Cross-link to /handbook/de/contracts/dienstvertrag.html for the contrast with the Dienstvertrag, which has no Abnahme mechanism at all.

Court Precedent

BGH VII ZR 198/14 (2016) is one of the most cited decisions on Vertragsstrafe magnitude in Werkverträgen. The BGH reiterated its earlier doctrine: in Werkvertrag-AGB used by the customer against the contractor, a Vertragsstrafe exceeding five percent of the agreed Vergütung is unreasonably disadvantageous to the contractor under § 307 Abs. 1 BGB and therefore invalid. The decision is the doctrinal anchor for the five-percent benchmark in construction and software contracting and feeds the drafting discipline on penalty caps discussed under Optional and Recommended Clauses above.

BGH on konkludente Abnahme is a long line of decisions establishing that Abnahme under § 640 BGB can be inferred from conduct: payment of the final invoice in full and without reservation, continued use of the Werk for an extended period without defect notification, signed handover protocols even without the word Abnahme, and equivalent conduct. The decisions matter because they routinely defeat Werkunternehmer who keep delivering “minor improvements” months after the Werk is in productive use under the assumption that Abnahme has not occurred — the warranty clock has typically been running for some time. The lesson for both parties is to document the Abnahme moment expressly rather than rely on silence.

Common Pitfalls

Six recurring failure modes deserve flagging. First, confusing Werkvertrag with Dienstvertrag: titling the document Werkvertrag while the substance is a time-and-materials advisory engagement, or vice versa — courts apply the substantive test and disregard the label, with the warranty regime, the Vergütungsstruktur and the Abnahme mechanics all shifting depending on which type controls. Second, missing or vague Werkbeschreibung: without an enforceable specification, the Mängelbegriff collapses into a vague übliche Beschaffenheit test and the Mängelhaftung is effectively unenforceable. Third, unclear Abnahmekriterien: a project where the customer keeps asking for “one more iteration” while the contractor insists the Werk is ready frequently sits in Abnahmestreit for months, with both Vergütung and the warranty clock hanging unresolved. Fourth, AGB warranty reductions below the statutory floor of § 634a BGB — automatically void in B2C and through § 307 BGB Indizwirkung in B2B. Fifth, AGB liability exclusion for gross negligence — automatically void per § 309 Nr. 7 BGB in B2C and through § 307 BGB Indizwirkung in B2B. Sixth, undocumented Abnahme by conduct — the contractor and the customer both lose certainty over when the warranty clock started running, and the resulting Verjährung-defence in a later Mängelstreit turns on a fact-pattern reconstruction nobody can win cleanly.

The integrating discipline is matching the contract type to the substance of the work, drafting an enforceable Werkbeschreibung, designing the Abnahmeverfahren explicitly, and respecting the statutory floors of § 634a BGB and § 309 Nr. 7 / Nr. 8 BGB in any AGB context. A correctly typed and disciplined Werkvertrag gives both parties predictable economics; a sloppy one feeds Abnahme-and-Mängel litigation that often costs more than the original project.

Disclaimer: This content is informational, not legal advice. Last verified: 2026-05-10. Always consult licensed counsel for binding decisions.