Francisco Rodriguez challenges the 168-month sentence imposed for his conviction for possession, with intent to distribute, 500 grams or more of methamphetamine, in violation of 21 U.S.C. § 841(a)(1). He claims the sentence is procedurally unreasonable because the district court failed to adequately explain it.

Although post -Booker, the Sentencing Guidelines are advisory only, and a properly preserved objection to an ultimate sentence is reviewed for reasonableness under an abuse-of-discretion standard, the district court must still properly calculate the advisory Guidelines-senteneing range for use in deciding on the sentence to impose. Gall v. United States, 552 U.S. 38, 51, 128 S.Ct. 586, 169 L.Ed.2d 445 (2007). In that respect, for issues preserved in district court, its application of the Guidelines is reviewed de novo; its factual findings, only for clear error. E.g., United States v. Cisneros-Gutierrez, 517 F.3d 751, 764 (5th Cir . 2008).

But, Rodriguez did not raise this issue in district court; therefore, review is only for plain error. E.g., United States v. Broussard, 669 F.3d 537, 546 (5th Cir. 2012). Under that standard, he must show a forfeited plain (clear or obvious) error that affected his substantial rights. Puckett v. United States, 556 U.S. 129, 135, 129 S.Ct. 1423, 173 L.Ed.2d 266 (2009). If he does so, we have the discretion to correct the error, but should do so only if it seriously affects the fairness, integrity, or public reputation of the proceedings. Id.

At sentencing, the district court stated that it had considered the 18 U.S.C. § 3553(a) sentencing factors. In any event, because the sentence imposed was within the advisory-Guidelines-sentencing range, little explanation of the sentence was required, Rita v. United States, 551 U.S. 338, 356-57, 127 S.Ct. 2456, 168 L.Ed.2d 203 (2007); and our court will infer the district court considered the' § 3553(a) sentencing factors, e.g., United States v. Mares, 402 F.3d 511, 519 (5th Cir. 2005). Therefore, even assuming ar-guendo the district court erred, Rodriguez has not shown that his substantial rights were affected. E.g., United States v. Mondragon-Santiago, 564 F.3d 357, 365 (5th Cir. 2009).

AFFIRMED.