Definition
Per my et per tout (Law French: "by the half and by the whole") is a technical phrase describing the distinctive manner in which joint tenants hold their estate. Each joint tenant simultaneously holds the entirety of the property and only a fractional share of it — the whole for purposes of tenure and survivorship, but only a proportional part (presumed equal) for purposes of alienation.
The phrase captures the legal paradox at the heart of joint tenancy: no single joint tenant owns a distinct, partitioned share of the land. Instead, each co-owner's seisin extends to every parcel and to the whole. Yet if a joint tenant conveys their interest, they can transfer only their own undivided share — severing the joint tenancy as to that portion — because they do not hold the whole in a way that permits unilateral disposal of more than their own interest.
Common Language
This is pure legal jargon. "My" here is not the English possessive pronoun but the Law French word for "half" or "moiety" (from the Old French "mi," meaning middle or half). "Tout" is Law French for "all" or "whole." There is no common English usage of this phrase, and no meaningful gap to reconcile.
Core Elements
The phrase encodes a two-part holding structure:
BY THE WHOLE (per tout): Each joint tenant is seised of the entirety of the estate. This is the foundation of survivorship — because each already holds the whole, the death of one joint tenant does not transfer property to the survivors so much as it removes an encumbrance on a title the survivors already hold.
BY THE HALF (per my): For purposes of alienation, each joint tenant is treated as holding only their proportional, undivided share. A joint tenant may convey, mortgage, or otherwise deal with that share. Doing so severs the joint tenancy as to that interest, typically converting it to a tenancy in common between the grantee and the remaining joint tenants.
Why It Matters in Research
Researchers will encounter per my et per tout almost exclusively in historical real property sources. It is the doctrinal engine behind the right of survivorship and is essential to understanding why survivorship operates as it does — not as an inheritance or transfer of title at death, but as the natural consequence of a title structure in which each tenant already held the whole.
The phrase appears in primary sources through the nineteenth century and into early twentieth-century treatises. Modern American property scholarship rarely uses the Law French form, preferring plain-English descriptions of joint tenancy mechanics. When reading older cases or equity proceedings involving co-ownership disputes, partition actions, or the severance of joint tenancies, this phrase signals that the court is reasoning from classical common law co-tenancy doctrine.
A key research trap: the phrase can be mistakenly read as describing only the survivorship feature of joint tenancy, when it equally describes the alienation limitation. Courts and treatise writers sometimes emphasize one dimension over the other depending on the issue before them. Read carefully for which half of the per my / per tout duality the source is actually addressing.
The phrase has no direct analog in tenancy in common doctrine. Tenants in common hold per my but not per tout — they have a distinct, alienable share but no claim to the whole and no survivorship right. This contrast is frequently drawn in historical sources and is useful for understanding why joint tenancy was historically disfavored in American law and why many states require express language to create it.
Historical Dictionary Support
Black's first and second editions are in close agreement, both rendering the phrase as "by the half and by the whole" and anchoring it to joint tenancy. The second edition is more precise, explicitly noting that the whole is held for purposes of tenure and survivorship while the fractional share governs alienation, and citing Washburn's Real Property for support.
Burrill adds useful texture by quoting Blackstone's Commentaries directly — "having each the entire possession as well of every parcel as of the whole" — and citing Hilliard's Real Property alongside it. Burrill's formulation, "by the half or moiety, and by all," emphasizes that the fractional interest is a moiety, which in classical usage means one half of two equal shares. This is slightly more specific than Black's phrasing and reflects the traditional assumption of equal shares among joint tenants.
None of the historical dictionaries address what happens when joint tenancy involves more than two tenants, where "per my" no longer corresponds to a strict half but to an equal fractional share. This is a gap in the historical treatments that modern real property scholarship addresses.
Jurisdictional Note
The phrase is a common law concept and appears uniformly across jurisdictions that received English common law. However, because many American states have modified or disfavored joint tenancy by statute — some requiring express language to create it and others abolishing it in certain contexts — the practical operation of per my et per tout doctrine varies considerably. Researchers working in community property states should be especially cautious about assuming common law joint tenancy rules apply without modification.