How do you cite a Supreme Court slip opinion, and when do you switch to U.S. pages?

Short answer. Until the decision has pages in the United States Reports, cite the slip opinion by docket number, slip page and full date. If you don't need a pinpoint, the volume number with the page left blank also works. When the official pages appear, switch to the U.S. citation and find every pinpoint and quotation again in the new version. Never guess a U.S. page.

The slip-opinion form [Convention]
Trump v. Barbara, No. 25-365, slip op. at 22 n.4 (U.S. June 30, 2026) (Thomas, J., dissenting).
The docket number identifies the case, "slip op. at 22 n.4" is footnote 4 on page 22 of the opinion cited (here Justice Thomas's dissent) in the Court's PDF, and "U.S." with the full date marks a Supreme Court decision that has no reporter page yet.
[Convention] In a slip opinion each opinion has its own page numbers, so name the opinion when it is not the Court's. Barbara's PDF has a page 22 in Justice Thomas's dissent and another in Justice Alito's.
[Convention] Pinpoint the opinion's pages, not the syllabus. The syllabus at the front of the PDF is the Reporter of Decisions' summary, numbered on its own, and the Court's own note says it is no part of the opinion.
Short form: Barbara, slip op. at 22 n.4 (Thomas, J., dissenting).

No pinpoint needed? [Convention]
Give the volume and leave the page blank:
West Virginia v. B.P.J., 609 U.S. ___ (2026).
When we checked on October 20, 2026, the Court's opinions page still gave that June 30, 2026 decision no page. The Court uses blanks the same way: the running head on alternate pages of Barbara's slip opinion, decided the same day, gives the volume, 609, and a blank line where the first page will go.

What changed between the slip and the print
Take Brownback v. King, decided February 25, 2021. On page 6 of its slip opinion the Court quoted an earlier case: a judgment is on the merits if the decision "actually passes directly on the substance of a particular claim before the court," followed by "(cleaned up)." In the preliminary print, the same sentence puts inner quotation marks around "passes directly on the substance of a particular claim" and ends "(brackets omitted)." Same passage, different quotation, so a quote copied from the slip may no longer match.
In the same slip opinion, a cite to another recent decision by its slip page reads "(slip op., at 6)," with a comma. That comma is the Court's house style; the national form writes "slip op. at 6."

When the U.S. pages exist [Convention]
Brownback v. King, 592 U.S. 209, 215 (2021).
Short form: Brownback, 592 U.S. at 215.
[House style] Find the passage again on the new pages instead of working out the page by arithmetic. Slip page 6 of Brownback starts on page 215 and ends on page 216, so only the passage itself tells you which page to cite. Then reread each quotation against the new text: the preliminary print warns that it "is subject to formal revision before the bound volume is published."

In between [Jurisdiction-specific] Some courts set an order for the commercial reporters before U.S. pages exist. For a decision not yet in the official reports, the Third Circuit's rule allows, in that order of preference, the Supreme Court Reporter, the Lawyers' Edition or United States Law Week (with the month, day and year). 3d Cir. L.A.R. 28.3(a).

Common mistakes
A guessed U.S. page, or a page taken from a news story or a database preview.
A pinpoint to the syllabus.
Slip pages left in after the U.S. pages exist, or a slip page attached to a U.S. citation.
"(2026)" alone in a slip cite. Without a reporter page, give the full date.

Read more
The Cases chapter (its opening is free to read): https://citationcode.com/book/cases (opens in a new tab)
Supreme Court citations, including one with the page still blank, each checked against its source: https://citationcode.com/examples/how-to-cite-a-us-supreme-court-opinion (opens in a new tab)