¶1*869Richard L. Johnson, Sioux Falls, SD, for appellant.
¶2Jan L. Holmgren, Asst. U.S. Atty., Sioux Falls, SD, for appellee.
¶3Before MELLOY, HANSEN, and GRUENDER, Circuit Judges.
¶5Appellants, all inmates at the Yankton Federal Prison Camp in South Dakota, appeal the district court’s1 denial of‘their consolidated 28 U.S.C. § 2241 habeas petitions, in which they challenge the Bureau of Prisons’ (BOP) calculation of their good conduct time (GCT) under 18 U.S.C. § 3624.2 Appellants contend that 'their GCT should be calculated based upon the length of incarceration imposed at sentencing, rather than — as provided by BOP policy, set out at 28 C.F.R. § 523.20 (2005)— based on the time actually served by the inmate.
¶6We conclude that section 3624(b) is ambiguous because it does not clearly indicate whether a prisoner’s GCT is based on the time served in prison or the sentence imposed. Because section 3624(b) is ambiguous, we must defer to the BOP’s interpretation if it is reasonable. See Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc., 467 U.S. 837, 844-45, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984). We agree with our sister circuits that the BOP’s interpretation of section 3624(b) is reasonable. See Brown v. McFadden, 416 F.3d 1271, 1273 (11th Cir.2005) (per curiam) (finding § 3624(b)(1) ambiguous and holding BOP policy of calculating GCT based on actual time served is entitled to deference as it is reasonable); Yi v. Fed. Bureau of Prisons, 412 F.3d 526, 533-34 (4th Cir.2005) (same); Sample v. Morrison, 406 F.3d 310, 313 (5th Cir.2005) (per curiam) (same); O’Donald v. Johns, 402 F.3d 172, 174 (3d Cir.2005) (per curiam) (same); Perez-Olivio v. Chavez, 394 F.3d 45, 51-53 (1st Cir.2005) (same); White v. Scibana, 390 F.3d 997, 999-1003 (7th Cir. 2004) (same), cert. denied, — U.S.-, 125 S.Ct. 2921, 162 L.Ed.2d 297 (2005); Pacheco-Camacho v. Hood, 272 F.3d 1266, 1270-71 (9th Cir.2001) (same), cert. denied, 535 U.S. 1105, 122 S.Ct. 2313, 152 L.Ed.2d 1067 (2002).
¶7Appellants’ remaining argument is that, even if section 3624(b) is ambiguous, the district court should have applied the rule of lenity and resolved the ambiguity in their favor. This argument lacks merit. We do not resort to the rule of lenity where, as here, we can otherwise resolve the ambiguity of the statute. See O’Donald, 402 F.3d at 174; Perez-Olivio, 394 F.3d at 53-54.
¶8Accordingly, we affirm the judgment of the district court.