Definition
A Latin maxim from Roman civil law meaning "I give that you may do" or, more fully, "I give to you so that you may do or make for me." Do ut facias describes a class of contract in which one party transfers money or property to another, and the consideration for that transfer is the second party's performance of work or services. The formula captures the exchange structure: a present gift or payment in return for a future act.
In civil law taxonomy, do ut facias was one of the foundational formulas used to classify the consideration moving between contracting parties. The related formulas—do ut des (I give that you may give), facio ut des (I do that you may give), and facio ut facias (I do that you may do)—together covered the full matrix of bilateral exchanges. Do ut facias occupies the quadrant where the first party's contribution is a giving (money, goods, property) and the second party's reciprocal obligation is doing (labor, service, manufacture).
Common Confusion
The conjunction "ut" in do ut facias should not be read as a term of art introducing a condition or contingency. As both Black's and Burrill's note, "ut" here is the ordinary Latin particle expressing purpose or exchange, not a technical conditional marker. Researchers encountering the phrase in civil law commentary should read it as expressing the logic of consideration—what is given and what is owed in return—not as imposing a conditional precedent to formation.
Do ut facias is also frequently grouped loosely with do ut des without distinguishing which formula applies. The difference matters: do ut des describes a thing-for-thing exchange (barter, sale), while do ut facias describes a money-or-property-for-services exchange (hire, commission, service contract). Confusing them distorts the civil law's careful classification of innominate contracts.
Why It Matters in Research
Researchers working in Roman law sources, early common law treatises, or comparative contract literature will encounter do ut facias as a classification device rather than a standalone doctrine. Its primary research value is as an organizing principle: when civil law commentators classify an agreement under this formula, they are identifying the structural logic of the exchange, which in turn determines which remedies and rules apply.
In common law sources, the phrase appears most often in discussions of consideration, where English writers used the Roman formulas to articulate what "valuable consideration" means in practice. Blackstone's Commentaries (2 Bl. Comm. 444) invokes the formula in this context, making it a bridge term between Roman taxonomy and common law doctrine. Researchers tracing the development of consideration doctrine should treat do ut facias as a connecting thread between civil law sources and early English contract commentary.
The formula also appears in treatments of innominate contracts—agreements that did not fit the named Roman contract categories (sale, hire, loan). Do ut facias was one of four formulas used to give those unnamed agreements a doctrinal home. When reading Digest 19.5 (the primary source cited across all dictionary entries), researchers should understand that the text is addressing contracts that fall outside the nominate categories and that the formula is the civil law's mechanism for extending contractual obligation to cover them.
No direct doctrinal carry-forward into modern American or English statute should be expected. The phrase functions in modern legal research primarily as a term of art in legal history, comparative law, and jurisprudence, not as operative law.
Historical Dictionary Support
The dictionary sources are in close agreement. Black's (both editions) and Burrill's provide substantively identical definitions, both citing Digest 19.5.5 and 2 Blackstone's Commentaries 444. Burrill's adds a useful illustrative example: "Do tibi codicem, ut facias mihi scribi digestum"—I give you a codex, that you may have a digest written for me—which concretizes the abstract formula. Bouvier's entry is minimal, directing the reader to the CONSIDERATION entry rather than defining the term independently.
None of the historical entries situate do ut facias within the full four-formula system, which is a gap for researchers who need to understand how the formulas relate to one another. The fuller picture—do ut des, do ut facias, facio ut des, facio ut facias—appears in the Digest and in Blackstone but not in the dictionary entries themselves. Researchers should go directly to those primary sources rather than relying on the dictionary entries for the complete taxonomy.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Consideration; Innominate Contracts; Roman Law Foundations of Contract.