UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE

SECURITIES EXCHANGE ACT OF 1934

For the month of February 2026

Commission File Number: 001-39127

Canaan Inc.

28 Ayer Rajah Crescent

#06-08

Singapore 139959

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F x            Form 40-F ¨

On February 10, 2026, Canaan Inc. (the “Company”) issued a press release announcing the Company’s financial results and business updates for the fourth quarter and full year 2025.

Exhibit 99.1 to this Form 6-K (excluding the statements set forth under the section headed “Business Outlook” contained in Exhibit 99.1) is hereby incorporated by reference into the Company’s Registration Statement on Form F-3 (File No. 333-285125).

EXHIBITS

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: February 10, 2026