The defendant, Jason Frankovich, pleaded guilty to a charge of conspiracy to manufacture more than 100 marijuana plants. He now appeals the 60-month prison term imposed upon him for that offense, alleging that the district court improperly increased his criminal history category by including in its sentencing determination under the guidelines a juvenile conviction for “open intoxicants in motor *327vehicle—passenger.” We find no reversible error in the calculation of the defendant’s sentence, and we therefore affirm the judgment of the district court.
At his guilty plea hearing, the defendant admitted—in his own words—that he “knowingly and intentionally conspired with Brian Lee Casey to manufacture more than 140 marijuana plants in the Hiawatha National Forest on or about March of 2003; and in around September of 2003, in the fall time, was apprehended for doing so.” In exchange for the government’s promise to dismiss two other charges lodged against him, Frankovich entered a plea of guilty to a charge of conspiracy to manufacture more than 100 marijuana plants and agreed to waive “the right to appeal any sentence which is at or below the maximum of the guidelines range as determined by the Court.”
The United States Probation Office conducted a presentence investigation of Frankovich and recommended, in light of the defendant’s prior criminal record, that he be sentenced under the then-mandatory United States Sentencing Guidelines as an offense level 17, criminal history category III offender. The defendant would thus presumptively have been subject to a prison sentence of between 30-37 months. Because 21 U.S.C. § 841(b)(1)(B)(vii) imposes a mandatory minimum sentence of five years for a drug law violation involving “100 or more marijuana plants regardless of weight,” however, the probation officer recommended a 60-month prison sentence for Frankovich. The prosecution lodged an objection to Frankovich’s criminal history category, asserting that the probation office should also have added an additional criminal history point to its calculation because of the defendant’s juvenile conviction in Michigan state court for possessing an open container of an intoxicant while a passenger in a motor vehicle. The district court agreed with the government’s position and determined that the additional criminal history point would subject the defendant to sentencing as a criminal history category IV offender, rather than as a criminal history III offender. Although such a designation would ordinarily result in a prison sentence of 37-46 months, the mandatory minimum sentence provisions of 21 U.S.C. § 841(b)(l)(B)(vii) nevertheless required the district court to sentence the defendant to 60 months’ incarceration.
On appeal, both the government and the defendant agree that the waiver contained in the plea agreement they executed does not prevent the defendant from contesting the imposition of the additional criminal history point to the criminal history category calculation, given explicit language in the agreement permitting Frankovich to appeal any sentence imposed above the applicable guideline range. Because the defendant’s 60-month sentence exceeded even the high end of the 37-46-month range found appropriate under the guidelines by the district court, the terms of the plea agreement do not foreclose this appeal.
We nevertheless conclude that the question presented on appeal raises an issue that Federal Rule of Criminal Procedure 52(a) renders moot. That rule provides that “[a]ny error, defect, irregularity or variance which does not affect substantial rights shall be disregarded.” As noted earlier, the applicable federal statute—21 U.S.C. § 841(b)(l)(B)(vn)—imposes a mandatory minimum sentence of 60 months upon an individual convicted of the offense to which Frankovich pleaded guilty. Consequently, whether the district court considered the defendant to be a category III offender subject to a range of 30-37 months or a category IV offender subject to a range of 37-46 months is irrelevant. Under the facts of this case, the district judge was bound by statute to impose a *328sentence no lower than the 60-month sentence he ultimately imposed. Frankovich has thus failed to establish any prejudice from the alleged error.1
Because the sentencing error alleged by Frankovich could not have affected his sentence, he is not entitled to relief. We therefore AFFIRM the judgment of the district court in its entirety.