SUMMARY ORDER

Defendant-appellant James Mack appeals from the district court’s sentence of 77 months of incarceration for possession with intent to distribute crack. We assume the parties’ familiarity with the underlying facts, the procedural history of the case, and the issues on appeal.

Mack argues that it was error under Sentencing Guidelines Section 1B1.3 to consider as relevant conduct his attempt to *757 purchase more than 500 grams of cocaine 14 months prior to his crack arrest. Mack did not present this argument to the district court, and it is therefore reviewed for plain error. United States v. Cossey, 632 F.3d 82, 86-87 (2d Cir. 2011). “To establish plain error, the Court must find (1) an error, (2) that is plain, (3) that affects substantial rights.” United States v. Doe, 297 F.3d 76, 82 (2d Cir. 2002).

“Factors that are appropriate to the determination of whether offenses are sufficiently connected or related to each other to be considered as part of the same course of conduct include the degree of similarity of the offenses, the regularity (repetitions) of the offenses, and the time interval between the offenses. When one of the above factors is absent, a stronger presence of at least one of the other factors is required.” U.S.S.G. § 1B1.3 cmt. 9(B).

At sentencing, the district court found, in conelusory fashion, that the allegations involving the cocaine charge “are connected to and part of the same type of conduct that the defendant was arrested for ... [i]t is clear that it is the relevant conduct that must be considered.” Sentencing Hr’g Tr. at 12-13, ECF No. 78.

Viewing the cocaine and crack incidents alone, it is difficult to see how the court could reasonably have found either sufficient proximity or regularity to support a relevant conduct enhancement. The 14-month gap exceeds the proximity parameters referenced in United States v. Santiago, 906 F.2d 867, 872 (2d Cir. 1990) (“8-14 months” was “considerably longer than the periods involved in most of our prior cases construing the Guidelines”). And it is hard to detect “regularity” in the two isolated incidents. While the similarity factor is supported by Mack’s possession with intent to distribute two related narcotics, see United States v. Burnett, 968 F.2d 278, 280 (2d Cir. 1992), it is an insufficient similarity to compensate for the absence of the other two factors, see U.S.S.G. § 1B1.3 cmt. 9(B).

Nevertheless, there was no plain error in this case. The district court could have referenced Mack’s glaring admission that “[h]e started selling drugs when he was younger with neighborhood friends” and “typically sold eightball to one-fourth ounce quantities of crack [earning] about $200 per week.” Pre-Sentence Report ¶ 17, ECF No. 59 (the district court adopted the findings of the PSR during the sentencing colloquy). Such admissions to probation officers may be used to estimate drug trafficking history for purposes of determining relevant conduct. See United States v. Colon, 961 F.2d 41, 43 (2d Cir. 1992). Mack’s admission clearly supports the requisite U.S.S.G. § 1B1.3 regularity factor missing from the district court’s relevant conduct analysis. For that reason, the relevant conduct enhancement was not plain error.

We have considered all of Mack’s remaining arguments and find them to be without merit. Accordingly, the judgment of the district court is hereby AFFIRMED.