Construction delayed? Calculate your damages.

The basis is art. 43-A of Law 4,591/1964, added by Law 13,786/2018 (the "Termination Law"). The main clause provides that delivery "within 180 (one hundred and eighty) calendar days of the date contractually set as the expected date for completion of the development, provided this is expressly agreed, clearly and prominently", gives the buyer no ground to terminate and triggers no penalty for the developer. § 2 is the source of the 1%: once that period is exceeded and there is no termination, "the compliant buyer shall be owed, upon delivery of the unit, compensation of 1% (one per cent) of the amount actually paid to the developer for each month of delay, pro rata die, adjusted for inflation according to the index set in the contract". § 1 covers the other route: a buyer who did not cause the delay may terminate the contract, with return of the entirety of the amounts paid and of the agreed penalty, within 60 calendar days, adjusted under § 8 of art. 67-A. And § 3 forbids stacking the two — the monthly compensation of § 2 addresses late performance, while the penalty of § 1 addresses total non-performance. That whole regime, however, only reaches contracts signed on or after 28 December 2018, for the reason the next item explains.

The cut-off date: 28 December 2018

Law 13,786/2018 was published in the Federal Official Gazette on 28 December 2018 and, under its art. 4, came into force on the date of publication. That is why the 1%-per-month figure in art. 43-A, §2, is the statutory benchmark for contracts signed on or after 28 December 2018. For earlier ones, the Superior Court of Justice (STJ), when ruling on the repetitive appeals about construction delay, held that Law 13,786/2018 does not apply to contracts signed before it came into force (REsp 1.498.484/DF, Second Section, judged on 22 May 2019), on the basis of art. 5, XXXVI, of the Constitution and art. 6, §2, of the Law of Introduction to the Rules of Brazilian Law (LINDB) — a position repeated by the panels (REsp 1.947.698/MS, Fourth Panel, judged on 8 March 2022). One precision, to avoid a common misreading: that non-retroactivity sits in the reasoning and the headnote of the leading judgment, and is not a standalone repetitive-appeal thesis.

In a contract signed before 28 December 2018, therefore, the benchmark for late-performance damages is the penalty clause of the contract itself: in Topic 970 (REsp 1.498.484/DF, Second Section, judged on 22 May 2019) the STJ held that the moratory penalty clause serves to compensate for late performance of the obligation and, as a rule, where set at an amount equivalent to the rental value, rules out its accumulation with lost profits. If the clause sets 0.5%, then it is 0.5%. And where an adhesion contract sets a penalty clause only for the buyer's default, Topic 971 (REsp 1.614.721/DF and 1.631.485/DF, Second Section, judged on 22 May 2019) requires that clause to be used in fixing the compensation for the seller's default, with heterogeneous obligations converted into money by judicial assessment. The Topic 970 judgment also records the judge's power and duty to review the penalty clause equitably (art. 413 of the Civil Code), even of their own motion. None of that is estimated by a formula: it depends on reading the contract.

A worked example

A contract signed after 28 December 2018 — the case in which art. 43-A, §2, applies. Assume R$ 300,000 actually paid and five full months of compensable delay already established after the applicable contractual deadline. The tool does not derive calendar dates or validate the grace clause. Monthly damages are R$ 300,000 × 1% = R$ 3,000, and the estimated total is R$ 15,000. Additional losses require proof and assessment of entitlement and permitted accumulation, without compensating the same loss twice. Article 43-A, § 3, prohibits adding the termination penalty to monthly delay compensation. Had the same contract been signed before 28 December 2018, that 1% line would not exist: its place is taken by the penalty clause of the contract.

Additional losses require proof and assessment of entitlement and permitted accumulation, without compensating the same loss twice. Article 43-A, § 3, prohibits adding the termination penalty to monthly delay compensation. The total is a simulation subject to its assumptions, not a guaranteed minimum award.

What the estimate leaves out

The statute counts the delay pro rata die; the calculator works in whole months — the number you type. That is a simplification adopted here, and the law does not fix it. Also excluded are inflation adjustment (which follows your contract's index, not a general one), interest, rent paid during the delay, the contractual penalty and any moral damages. The total is a simulation subject to its assumptions, not a guaranteed minimum award.

There is also what the tool does not check. It assumes your contract carries the express, clear and prominent grace clause the main clause requires — without it, the 180 days do not apply. It does not verify that you are current on your instalments, a condition of § 2, nor that the unit has been delivered, the moment when compensation falls due. And it assumes a condominium development (incorporação imobiliária): a plot bought in a land subdivision follows Law 6,766/1979, whose art. 32-A, also added by Law 13,786/2018, deals with termination for the buyer's default and sets no 1%-per-month figure.