Oklahoma: Prejudgment Interest Rules

The short answer

Oklahoma doesn't run a simple contract-versus-tort line for prejudgment interest --
it runs three separate tracks. A contract debt, or really any claim where the exact
dollar amount is fixed or can be calculated from known facts, draws interest
automatically from the day the right to be paid came into existence, at 6% a year or
the contract's own rate. A tort claim that doesn't fit that ascertainable-damages
mold -- most property-damage and business-tort claims, plus any case involving fraud,
oppression, or malice -- can still draw interest, but only if the jury decides, in its
own discretion, to award it. And a personal-injury or personal-rights tort claim
(bodily injury, defamation, invasion of privacy, and similar harms) runs on a
completely separate statute built just for that category: the court must add
interest to the verdict at a floating Treasury-bill rate, but the clock doesn't even
start until 24 months after the lawsuit was filed -- a built-in waiting period unlike
anything else in this survey.

Requirements one by one

Governing law

Two entirely separate statutory schemes do the work. 23 O.S. §§ 6-8 (Title 23,
Damages) set the general rule for contract claims and most torts: § 6 makes interest
mandatory once damages are ascertainable, § 7 lets a jury award interest at its
discretion for other non-contract claims and cases of fraud, oppression, or malice,
and § 8 says accepting the full principal waives any claim to interest on it.
Separately, 12 O.S. § 727.1 -- the same section that sets Oklahoma's postjudgment
interest rate -- devotes subsections (E) through (I) to a dedicated, purpose-built
prejudgment-interest mechanism just for personal-injury and personal-rights tort
verdicts.

Interest rate

For a claim under the general 23 O.S. §§ 6-7 track, the rate is Oklahoma's 6% "legal
rate" under 15 O.S. § 266, unless the parties' own contract sets a different rate.
For a personal-injury/personal-rights verdict under 12 O.S. § 727.1(E), the rate is
entirely different: the average U.S. Treasury Bill rate of the PRECEDING calendar
year, certified annually by the State Treasurer, and reset each January 1 for
judgments that remain pending into a new calendar year.

When interest starts running

Under the general track, interest starts the day the right to recover "vested" --
the day the debt or ascertainable claim became due. Under the personal-injury track,
interest doesn't start on the date of injury, or even the date suit was filed --
it starts 24 months AFTER the suit was commenced, and runs from there to the earlier
of the date the verdict is accepted or the judgment is filed. That 24-month blackout
period is a deliberate legislative choice, not an accident of drafting: no other
state in this survey delays the start of prejudgment interest by a fixed period tied
to the litigation's own timeline.

Contract vs. tort claims

This is Oklahoma's central axis, and it's a three-way split rather than a clean
binary. (1) Contract debts and any claim -- contract or tort -- with ascertainable
damages draw interest automatically under 23 O.S. § 6. (2) A tort claim that doesn't
have a fixed or calculable dollar figure, or a case involving fraud, oppression, or
malice, can still draw interest, but only if the jury chooses to award it under § 7.
(3) A personal-injury or personal-rights tort verdict -- the statute's own list
includes bodily restraint, personal insult, defamation, invasion of privacy, and
injury to personal relations -- runs on the separate, mandatory 12 O.S. § 727.1(E)
mechanism instead, bypassing both § 6 and § 7 entirely.

Mandatory or discretionary

All three tracks answer this question differently. Ascertainable-damages claims
under § 6 are mandatory -- a qualifying claimant "is ... entitled also to recover
interest," with no discretion built in. Other non-contract claims and fraud/
oppression/malice cases under § 7 are discretionary, and that discretion belongs to
the JURY, not the judge -- an unusual allocation compared to most other states in
this survey, where a discretionary award (if any) is the court's call. Personal-
injury/personal-rights verdicts under 12 O.S. § 727.1(E) are mandatory again, but
this time it's the court, not the jury, that "shall add interest on the verdict."

Simple or compound

None of the governing statutes -- 23 O.S. §§ 6-8 or 12 O.S. § 727.1(E)-(I) -- say
anything about compounding for the prejudgment period. Absent statutory language
requiring compounding, the interest computed under either track is calculated as
simple interest on the principal amount.

Claims against the government

A personal-injury/personal-rights verdict against the State of Oklahoma or one of
its political subdivisions (counties, municipalities, school districts, and public
trusts) runs under its own subsection, 12 O.S. § 727.1(F). The accrual date is more
favorable to the claimant than the private-party rule: interest runs from the date
suit was commenced, with none of the 24-month delay that applies against a private
defendant. But the total recovery -- the underlying judgment plus any prejudgment
interest -- can never exceed the liability caps the Governmental Tort Claims Act sets
for that type of governmental entity, so the interest can be squeezed out entirely
once the cap is reached.

Other exceptions

Exemplary or punitive damages draw no prejudgment interest at all: under 12 O.S. §
727.1(G), interest on a punitive award starts only from the date judgment is
rendered or filed -- purely postjudgment. A judgment establishing a property lien
with no other applicable interest rate gets its own rule, 12 O.S. § 727.1(H): interest
from the date the lien was filed to the date of the verdict. And under 23 O.S. § 8, a
creditor who accepts payment of the full principal amount waives any claim to
interest on it, even if interest had already started accruing.

What trips people up

Assuming a tort claim gets the same automatic treatment as a contract debt is the
first trap: unless the damages are genuinely ascertainable, a tort plaintiff needs the
jury to exercise its discretion under § 7, and a jury has no obligation to award
anything.

Assuming personal-injury interest starts running from the date of the injury, or even
the date suit was filed, is the second and biggest trap: it doesn't start for 24
months after the lawsuit was commenced, no matter how clear liability is or how early
the case settles into a predictable outcome.

Assuming the general 23 O.S. §§ 6-7 track applies to a personal-injury case at all is
a third trap -- it doesn't. Personal-injury and personal-rights claims are carved out
into the completely separate 12 O.S. § 727.1(E) mechanism, with its own rate and its
own accrual rule.

Common questions

What's Oklahoma's prejudgment interest rate?
6% for an ascertainable-damages claim under 23 O.S. §§ 6-7 (or the contract's own
rate), but the average U.S. Treasury Bill rate of the prior year for a personal-injury
or personal-rights tort verdict under 12 O.S. § 727.1(E).

Can I get prejudgment interest on an Oklahoma personal injury claim?
Yes, but not from the date of injury -- it only starts accruing 24 months after the
lawsuit was filed, and the court adds it automatically once the verdict is accepted.

Does a jury decide whether I get prejudgment interest in Oklahoma?
Only for an ordinary tort claim, or a fraud/oppression/malice case, under 23 O.S. §
7 -- that's the jury's discretionary call. Ascertainable-damages claims under § 6 are
automatic, and personal-injury verdicts under 12 O.S. § 727.1(E) are the court's
mandatory duty, not the jury's choice.

Can I get prejudgment interest against the State of Oklahoma or a county?
Yes, for a covered personal-injury/personal-rights verdict, from the date suit was
filed (no 24-month delay) -- but the total judgment, interest included, can't exceed
the Governmental Tort Claims Act's liability cap for that entity.

Statutes and sources

• 23 O.S. § 6 -- "Any person who is entitled to recover damages certain, or capable
  of being made certain by calculation, and the right to recover which is vested in
  him upon a particular day, is entitled also to recover interest thereon from that
  day." Accessed 2026-07-05:
  https://govt.westlaw.com/okjc/Document/N7CA33DF0C76C11DB8F04FB3E68C8F4C5?viewType=FullText
• 23 O.S. § 7 -- "In an action for the breach of an obligation not arising from
  contract, and in every case of oppression, fraud or malice, interest may be given in
  the discretion of the jury." Accessed 2026-07-05:
  https://govt.westlaw.com/okjc/Document/N7D3CBED0C76C11DB8F04FB3E68C8F4C5?viewType=FullText
• 23 O.S. § 8 -- "Accepting payment of the whole principal, as such, waives all claim
  to interest." Accessed 2026-07-05:
  https://govt.westlaw.com/okjc/Document/N7D67C670C76C11DB8F04FB3E68C8F4C5?viewType=FullText
• 15 O.S. § 266 -- "The legal rate of interest shall be six percent (6%) in the
  absence of any contract as to the rate of interest." Accessed 2026-07-05:
  https://govt.westlaw.com/okjc/Document/NA8227CD0C69911DB8F04FB3E68C8F4C5?viewType=FullText
• 12 O.S. § 727.1(E)-(I) -- sets the personal-injury/personal-rights prejudgment
  interest mechanism: mandatory court-added interest, a 24-month accrual delay, and
  the average-T-bill-rate formula, plus the government-defendant, punitive-damages,
  and lien-judgment carve-outs. Accessed 2026-07-05:
  https://law.justia.com/codes/oklahoma/title-12/section-12-727-1/