Relevant Background
{¶ 1} On May 21, 1998, appellant, Curtis Simpkins, pleaded guilty to two counts of rape in violation of R.C. 2907.02, felonies of the first degree, and to one count of gross sexual imposition in violation of R.C. 2907.05, a felony of the third degree. The trial court sentenced Simpkins on June 11, 1998, to a term of eight years’ incarceration for each count of rape and to three years’ incarceration for the single count of gross sexual imposition, to be served concurrently. Although postrelease control was required, see R.C. 2929.14(F) and 2967.28, the journal *421entry on sentencing did not indicate that Simpkins was subject to postrelease control. That error went uncorrected for more than seven years.
{¶2} In December 2005, however, the state moved to resentence Simpkins prior to his release from prison. The state asserted that the sentence imposed initially was void because it had not included postrelease control. The trial court held a hearing on the motion while Simpkins was still in custody and agreed that the initial sentence was void. The court resentenced Simpkins to the same sentence of incarceration imposed previously, but added a period of five years’ postrelease control. The journal entry for the resentencing hearing reflects the imposition of postrelease control.
{¶ 3} Simpkins appealed, arguing that our decision in Hernandez v. Kelly, 108 Ohio St.3d 395, 2006-Ohio-126, 844 N.E.2d 301, does not support the after-the-fact resentencing of a defendant who has nearly completed his sentence. The court of appeals rejected his claim.
{¶ 4} Relying on State v. Rutherford, Champaign App. No. 06CA13, 2006-Ohio-5132, 2006 WL 2795380, the court of appeals explained, “The trial court retained its jurisdiction to resentence appellant. R.C. 2967.28 mandates that a trial court impose a term of post-release control for the offenses to which appellant pleaded guilty; therefore, the trial court must impose post-release control orally at the sentencing hearing and transcribe such imposition in the court’s journal entry. Failure to do so renders the sentence void. State v. Jordan, 104 Ohio St.3d 21, 2004-Ohio-6085, 817 N.E.2d 864. Because appellant’s 1998 sentence was void, resentencing was a proper remedy to correct the trial court’s original error of omission. Id.; State v. Beasley (1984), 14 Ohio St.3d 74 [14 OBR 511], 471 N.E.2d 774.” State v. Simpkins, Cuyahoga App. No. 87692, 2006-Ohio-6028, 2006 WL 3317928, ¶ 11.
{¶ 5} We accepted appellant’s discretionary appeal, State v. Simpkins, 113 Ohio St.3d 1440, 2007-Ohio-1266, 863 N.E.2d 657, which presents a discrete proposition of law: “A defendant who has been sentenced to a term of imprisonment that does not include post-release control may not be sentenced anew in order to add post-release control unless the State has challenged the failure to include post-release control in a timely direct appeal.” For the reasons that follow, we reject that proposition.
{¶ 6} We hold that in cases in which a defendant is convicted of, or pleads guilty to, an offense for which postrelease control is required but not properly included in the sentence, the sentence is void, and the state is entitled to a new sentencing hearing to have postrelease control imposed on the defendant unless the defendant has completed his sentence.
*422Analysis
{¶ 7} This appeal requires us to balance the doctrine of res judicata, a defendant’s interest in the finality of his sentence, and the people’s interest in the imposition of lawful, proper sentences.
{¶ 8} Simpkins asserts initially that the state is barred by res judicata from challenging the trial court’s failure to include the period of postrelease control. Alternatively, he argues that he had a legitimate expectation of finality in his sentence and that the Double Jeopardy and Due Process Clauses of the federal constitution protect that expectation. We address these arguments in turn.
A
{¶ 9} Appellant suggests that the doctrine of res judicata prevented his resentencing, citing our decisions in Pratts v. Hurley, 102 Ohio St.3d 81, 2004-Ohio-1980, 806 N.E.2d 992, ¶ 12, and State v. Perry (1967), 10 Ohio St.2d 175, 180, 39 O.O.2d 189, 226 N.E.2d 104. The appellant’s reliance on Pratts and Perry is understandable but misplaced. Pratts and Perry address aspects of res judicata doctrine in collateral attacks on voidable judgments and are distinguishable from the specific context of the instant case.
(¶ 10} Here, we consider whether a defendant who was not sentenced properly to a statutorily mandated period of postrelease control can be resentenced if he is still imprisoned and there was no direct appeal from the judge’s sentencing error. That question is answered by a discrete line of decisions arising from cases that are more closely analogous to appellant’s case.
{¶ 11} Our analysis begins by making a key distinction that has been obscured in our law: the difference between sentences that are void and those that are voidable. We recognize that we have not always used these terms as properly and precisely as possible. See, e.g., State v. Payne, 114 Ohio St.3d 502, 2007-Ohio-4642, 873 N.E.2d 306, ¶ 34 (Lanzinger, J., concurring) (suggesting that the court had not properly used the term “void” and instead should have used the term “voidable” in referring to the sentences at issue in State v. Foster, 109 Ohio St.3d 1, 2006-Ohio-856, 845 N.E.2d 470, ¶ 103); Kelley v. Wilson, 103 Ohio St.3d 201, 2004-Ohio-4883, 814 N.E.2d 1222, ¶ 14 (“despite our language in [State v. Green (1998), 81 Ohio St.3d 100, 689 N.E.2d 556] that the specified errors rendered the sentence ‘void,’ the judgment was voidable and properly challenged on direct appeal”); State v. Parker, 95 Ohio St.3d 524, 2002-Ohio-2833, 769 N.E.2d 846, ¶ 20-26 (Cook, J., dissenting) (arguing that the majority opinion confused void and voidable judgments).
{¶ 12} In general, a void judgment is one that has been imposed by a court that lacks subject-matter jurisdiction over the case or the authority to act. State v. Payne, 114 Ohio St.3d 502, 2007-Ohio-4642, 873 N.E.2d 306, ¶ 27. Unlike a void *423judgment, a voidable judgment is one rendered by a court that has both jurisdiction and authority to act, but the court’s judgment is invalid, irregular, or erroneous. Id.
{¶ 13} Although we commonly hold that sentencing errors are not jurisdictional and do not necessarily render a judgment void, see State ex rel. Massie v. Rogers (1997), 77 Ohio St.3d 449, 450, 674 N.E.2d 1383; Johnson v. Sacks (1962), 173 Ohio St. 452, 454, 20 O.O.2d 76, 184 N.E.2d 96 (“The imposition of an erroneous sentence does not deprive the trial court of jurisdiction”), there are exceptions to that general rule. The circumstances in this case — a court’s failure to impose a sentence as required by law — present one such exception.
{¶ 14} In a narrow vein of cases running back to 1984, this court has held consistently that a sentence that does not contain a statutorily mandated term is a void sentence. State v. Beasley (1984), 14 Ohio St.3d 74, 14 OBR 511, 471 N.E.2d 774. In Beasley, the applicable sentencing statute required the judge to impose a prison term and permitted the judge to impose a fine. Id. at 75, 14 OBR 511, 471 N.E.2d 774. The trial court disregarded the statutory mandate and imposed only a fine. We held that the trial court had exceeded its authority by disregarding the statutory sentencing requirements and that the “attempted sentence” was a nullity and must be considered void. Id.
{¶ 15} Twenty years later, in State v. Jordan, 104 Ohio St.3d 21, 2004-Ohio-6085, 817 N.E.2d 864, we applied Beasley to a trial court’s failure to follow a statute that required the court to notify a defendant that he was subject to postrelease control. We recognized that “[t]he court’s duty to include a notice to the offender about postrelease control at the sentencing hearing is the same as any other statutorily mandated term of a sentence. And based on the reasoning in Beasley, a trial court’s failure to notify an offender at the sentencing hearing about postrelease control is error.” Id. at ¶ 26. We held that “[bjecause a trial court has a statutory duty to provide notice of postrelease control at the sentencing hearing, any sentence imposed without such notification is contrary to law” and void. Id. at ¶ 23. We thus concluded that the sentence imposed on Jordan must be vacated and that he must be resentenced. Id., citing Beasley, 14 Ohio St.3d 74, 14 OBR 511, 471 N.E.2d 774.
{¶ 16} Two years later, the issue resurfaced in two cases, Hernandez v. Kelly, 108 Ohio St.3d 395, 2006-Ohio-126, 844 N.E.2d 301, and State ex rel. Cruzado v. Zaleski, 111 Ohio St.3d 353, 2006-Ohio-5795, 856 N.E.2d 263. In each case, we were presented with a defendant who had not been properly sentenced to statutorily mandated terms of postrelease control as required by R.C. 2967.28(B). Although we reached different results as to the appropriate remedies for the failure to properly include the postrelease control, our analysis was consistent.
*424{¶ 17} In Hernandez, we held that the defendant could not be resentenced to the period of postrelease control that should have been imposed initially. Our holding there was driven by a critical fact: Hernandez had already completed the term of imprisonment that had been imposed properly by the trial judge. We held that an after-the-fact notification in those circumstances would have circumvented the objectives of R.C. 2929.14(F) and 2967.28, which were enacted to ensure accuracy in sentencing and proper notice to defendants. 108 Ohio St.3d 395, 2006-Ohio-126, 844 N.E.2d 301, at ¶ 28-29, citing State v. Brooks, 103 Ohio St.3d 134, 2004-Ohio-4746, 814 N.E.2d 837, ¶ 33. We could not condone a defendant’s being held for violating conditions of postrelease control that had not been imposed properly on him and of which he had not been properly notified— particularly when he had completed the portion of the sentence that had been imposed properly.1 Id. at ¶ 30-32.
{¶ 18} But in Cruzado, which involved a defendant who had not yet been released from prison and whose journalized sentence had not expired, the rationale for Hernandez was not compelling. Indeed, we expressly distinguished Cruzado from Hernandez, noting that “[b]ecause Cruzado’s sentence had not yet been completed when he was resentenced, [the trial judge] was authorized to correct the invalid sentence to include the appropriate, mandatory postreleasecontrol term.” 111 Ohio St.3d 353, 2006-Ohio-5795, 856 N.E.2d 263, ¶ 28.
{¶ 19} Shortly after our decision in Cruzado, we returned again to this area in State v. Bezak, 114 Ohio St.3d 94, 2007-Ohio-3250, 868 N.E.2d 961. In holding that a defendant is entitled to a new sentencing hearing in cases in which his sentence does not include the proper period of postrelease control, we reaffirmed the vitality of Jordan. We concluded that because Bezak had not been informed of postrelease control at his sentencing hearing, “the sentence imposed by the trial court is void. ‘The effect of determining that a judgment is void is well established. It is as though such proceedings had never occurred; the judgment is a mere nullity and the parties are in the same position as if there had been no judgment.’ (Citations omitted.)”2 Bezak, 114 Ohio St.3d 94, 2007-Ohio-3250, 868 *425N.E.2d 961, at ¶ 12, quoting Romito v. Maxwell (1967), 10 Ohio St.2d 266, 267-268, 39 O.O.2d 414, 227 N.E.2d 223.
{¶ 20} The underpinning of our decisions from Beasley to Bezak is the fundamental understanding that no court has the authority to substitute a different sentence for that which is required by law. Colegrove v. Bums (1964), 175 Ohio St. 437, 438, 25 O.O.2d 447, 195 N.E.2d 811. Because no judge has the authority to disregard the law, a sentence that clearly does so is void.
{¶ 21} Therefore, in circumstances in which the judge disregards what the law clearly commands, such as when a judge fails to impose a nondiscretionary sanction required by a sentencing statute, the judge acts without authority. Beasley, 14 Ohio St.3d at 75, 14 OBR 511, 471 N.E.2d 774. Such actions are not mere errors that render a sentence voidable rather than void. If a judge imposes a sentence that is unauthorized by law, the sentence is unlawful. “If an act is unlawful it not erroneous or voidable, but it is wholly unauthorized and void.” (Emphasis sic.) State ex rel. Kudrick v. Meredith (1922), 24 Ohio N.P. (N.S.) 120, 124, 1922 WL 2015, *3.
{¶22} Because a sentence that does not conform to statutory mandates requiring the imposition of postrelease control is a nullity and void, it must be vacated. The effect of vacating the sentence places the parties in the same position they would have been in had there been no sentence. Bezak, 114 Ohio St.3d 94, 2007-Ohio-3250, 868 N.E.2d 961, ¶ 13, citing Romito v. Maxwell (1967), 10 Ohio St.2d 266, 267, 39 O.O.2d 414, 227 N.E.2d 223.
{¶ 23} A trial court’s jurisdiction over a criminal case is limited after it renders judgment, but it retains jurisdiction to correct a void sentence and is authorized to do so. Cruzado, 111 Ohio St.3d 353, 2006-Ohio-5795, 856 N.E.2d 263, at ¶ 19; Jordan, 104 Ohio St.3d 21, 2004-Ohio-6085, 817 N.E.2d 864, at ¶ 23. Indeed, it has an obligation to do so when its error is apparent.
{¶ 24} Simpkins argues, and some courts have suggested, that res judicata prevents resentencing. See State v. Broyles, Stark App. No. 2006CA00170, 2007-Ohio-487, 2007 WL 352195, ¶ 13, fn. 2 (raising the question whether res judicata should be applied to the state in cases in which the state does not immediately appeal the failure to incorporate mandatory postrelease control into a sentence, *426given the state’s right to appeal sentences pursuant to R.C. 2953.08(B)(2) and (G), which had not been enacted when Beasley was decided). We conclude that res judicata does not prevent resentencing.
{¶ 25} Res judicata is a rule of fundamental and substantial justice, see State v. Szefcyk (1996), 77 Ohio St.3d 93, 95, 671 N.E.2d 233, citing Federated Dept. Stores, Inc. v. Moitie (1981), 452 U.S. 394, 401, 101 S.Ct. 2424, 69 L.Ed.2d 103, that “ ‘is to be applied in particular situations as fairness and justice require, and that * * * is not to be applied so rigidly as to defeat the ends of justice or so as to work an injustice.’ ” Grava v. Parkman Twp. (1995), 73 Ohio St.3d 379, 386-387, 653 N.E.2d 226 (Douglas, J., dissenting), quoting 46 American Jurisprudence 2d (1994) 786-787, Judgments, Section 522, and citing Goodson v. McDonough Power Equip., Inc. (1983), 2 Ohio St.3d 193, 202, 2 OBR 732, 443 N.E.2d 978. We would achieve neither fairness nor justice by permitting a void sentence to stand.
{¶ 26} Although res judicata is an important doctrine, it is not so vital that it can override “society’s interest in enforcing the law, and in meting out the punishment the legislature has deemed just.” Beasley, 14 Ohio St.3d at 75, 14 OBR 511, 471 N.E.2d 774.
{¶ 27} Every judge has a duty to impose lawful sentences. “Confidence in and respect for the criminal-justice system flow from a belief that courts and officers of the courts perform their duties pursuant to established law.” Cruzado, 111 Ohio St.3d 353, 2006-Ohio-5795, 856 N.E.2d 263, at ¶24. The interests that underlie res judicata, although critically important, do not override our duty to sentence defendants as required by the law.
{¶ 28} Similarly, a prosecutor cannot bind the people or a court to an unlawful or otherwise void sentence by failing to appeal it properly.
{¶ 29} Neither constitutional principles nor the doctrine of res judicata requires that sentencing become a game in which a wrong move by the judge or prosecutor means immunity for a defendant. See Bozza v. United States (1947), 330 U.S. 160, 166-167, 67 S.Ct. 645, 91 L.Ed. 818.
{¶ 30} Although res judicata applies to a voidable sentence and may operate to prevent consideration of a collateral attack based on a claim that could have been raised on direct appeal from the voidable sentence, State v. Perry (1967), 10 Ohio St.2d 175, 39 O.O.2d 189, 226 N.E.2d 104, we have not applied res judicata to cases in which the sentence was void. We decline to do so now. “[W]here no statutory authority exists to support a judgment, res judicata does not act to bar a trial court from correcting the error.” State v. Ramey, Franklin App. No. 06AP-245, 2006-Ohio-6429, 2006 WL 3518010, ¶ 12. See also State v. Barnes, Portage App. No. 2006-P-0089, 2007-Ohio-3362, 2007 WL 1881509, ¶ 49-51; State v. Rodriguez (1989), 65 Ohio App.3d 151, 154, 583 N.E.2d 347 (Quillin, J., dissenting) (“A void judgment can be attacked in post-conviction relief proceed*427ings even if the matter could have been, but was not, raised on direct appeal. If the appellants’ sentences are void, the doctrine of res judicata is inapplicable”).
B
{¶ 31} We now address an alternative argument raised by appellant: that he may not be resentenced because he had completed a substantial majority of his sentence at the time of resentencing and had a cognizable interest in the finality of his sentence. In support of his contention, he relies upon generalized due-process and double-jeopardy arguments that fail to establish his claim.
{¶ 32} We do not dispute that the Double Jeopardy Clause was designed, in part, to preserve the finality and integrity of judgments. Crist v. Bretz (1978), 437 U.S. 28, 33, 98 S.Ct. 2156, 57 L.Ed.2d 24; United States v. Scott (1978), 437 U.S. 82, 98 S.Ct. 2187, 57 L.Ed.2d 65. But the United States Supreme Court’s decisions in the sentencing area also “clearly establish that a sentence does not have the qualities of constitutional finality that attend an acquittal.” United States v. DiFrancesco (1980), 449 U.S. 117, 134, 101 S.Ct. 426, 66 L.Ed.2d 328. Although the Fifth Amendment to the United States Constitution imposes no absolute bar against an order increasing a defendant’s sentence, the Due Process Clause forbids any increase for the purpose of punishing a defendant for appealing or for deterring other appeals. See, e.g., North Carolina v. Pearce (1969), 395 U.S. 711, 723-726, 89 S.Ct. 2072, 23 L.Ed.2d 656; see also Ex Parte Lange (1873), 18 Wall. 163, 85 U.S. 163, 21 L.Ed. 872.
{¶ 33} As the federal appellate courts have recognized, “ ‘a trial court not only can alter a statutorily-invalid sentence in a way which might increase its severity, but must do so when the statute so provides.’ ” Breest v. Helgemoe (C.A.1, 1978), 579 F.2d 95, 99, quoting Thompson v. United States (C.A.1, 1974), 495 F.2d 1304, 1306 (emphasis in Thompson). “Even after the defendant has commenced to serve his sentence, that power and that obligation continue.” Id., citing United States v. Davis (C.A.D.C.1977), 561 F.2d 1014. In cases in which the increase to the defendant’s sentence is due to a “legally incomplete” sentence rather than in response to a mistake of fact, a change of heart, or vindictiveness, we find no due-process or other constitutional violation. See id. at 101. Accord United States v. Halper (1989), 490 U.S. 435, 450, 109 S.Ct. 1892, 104 L.Ed.2d 487 (indicating that in the multiple-punishments context of the Double Jeopardy Clause, the constitutional interest is “limited to ensuring that the total punishment did not exceed that authorized by the legislature”).
{¶ 34} In reaching the conclusion that there is no constitutional violation here, we recognize that Simpkins had completed the vast majority of his sentence at the time of his resentencing. We are also aware that some courts have expressed “concern that the power of a sentencing court to correct even a statutorily invalid *428sentence must be subject to some temporal limit” imposed by due process and fundamental fairness. Breest, 579 F.2d at 101. See also United States v. Arrellano-Rios (C.A.9, 1986), 799 F.2d 520, 525, fn. 3, and cases cited therein. Accord Hernandez, 108 Ohio St.3d 395, 2006-Ohio-126, 844 N.E.2d 301. Although Simpkins was near the end of a significant sentence, we discern no unfairness in his resentencing and no violation of due process.
(¶ 35} As we explained recently in In re C.S., 115 Ohio St.3d 267, 2007-Ohio-4919, 874 N.E.2d 1177, ¶ 80-81, due-process rights are malleable ones that are designed to ensure that individuals are treated with fundamental fairness in light of the given situation and the interests at stake.
{¶ 36} Where, as here, the sentence imposed was unlawful and thus void, there can be no reasonable, legitimate expectation of finality in it. United States v. Crawford (C.A.5, 1985), 769 F.2d 253, 257-258; Jones v. Thomas (1989), 491 U.S. 376, 395, 109 S.Ct. 2522, 105 L.Ed.2d 322 (Scalia, J., dissenting) (noting that a “defendant could not argue that his legitimate expectation of finality in the original sentence had been violated, because he was charged with knowledge that the court lacked statutory authority to impose the subminimum sentence in the first instance” [emphasis sic]). See also Warnick v. Booher (Okla.Crim.App. 2006), 2006 OK CR 41, 144 P.3d 897, ¶ 21 (“Any clerical error in [the Department of Corrections’] recordkeeping regarding the accumulation and/or reduction of credits and the completion date of the sentence is not grounds for release and does not create any expectation of finality short of serving the entirety of the actual sentence imposed”).
{¶ 37} Given that the sentence was issued without the authority of law and that Simpkins was represented by counsel, we find that there was no unfair surprise or prejudice to Simpkins in his resentencing. Because he did not have a legitimate expectation of finality in his sentence, Simpkins could be resentenced without offending the Double Jeopardy or Due Process Clauses.3 See United States v. Fogel (C.A.D.C.1987), 829 F.2d 77, 87.
*429{¶ 38} In some circumstances, including the completion of a sentence, it may be reasonable to find that a defendant’s expectation of finality in his sentence has become legitimate and must be respected. We find that this is not such a case, however, and thus leave that determination for another day.
Judgment affirmed.
Moyer, C.J., and Pfeifer, Lundberg Stratton, O’Donnell, and Cupp, JJ., concur.
Lanzinger, J., dissents.