FAY, Circuit Judge:

Bob Jay Cole, a Georgia prisoner, appeals the dismissal of his 28 U.S.C. § 2254 habeas petition as untimely. We affirm.

I. FACTUAL AND PROCEDURAL BACKGROUND

Cole, represented by attorney Pat Clements, pled guilty to malice murder and armed robbery in the Superior Court of Catoosa County, Georgia, on April 1, 1991.1 He was sentenced to two, concurrent life sentences. Cole did not file a direct appeal. On June 18, 2008, he filed a pro se Motion to Void Indictment and Conviction as Being Unconstitutional, which was denied in the Superior Court of Catoosa County. Order Denying Mot. to Void Indictment & Conviction (Ga.Super.Ct. July 1, 2008).

More than seventeen years after his guilty plea, Cole filed a counseled state habeas petition in the Superior Court of Tattnall County on July 1, 2008.2 He asserted three bases for his petition relative to his guilty plea. First, he argued he did not knowingly, intelligently, and voluntarily waive his constitutional rights under Boykin v. Alabama, 395 U.S. 238, 89 S.Ct. 1709, 23 L.Ed.2d 274 (1969).3 Second, he contended his plea was not knowing, intelligent, and voluntary, because he alleged he was informed by his counsel and the trial judge he would serve only seven years of his life sentences before being released on parole.4 Third, he asserted his plea counsel was ineffective, because he wanted to use a "battered spouse" defense,5 which Cole had rejected and was offered no alternative.

The state judge conducted an evidentiary hearing on May 20, 2009, after which Cole was permitted to supplement the record with additional exhibits. Another evidentiary hearing was held on September 22, 2010. A third hearing occurred on January 31, 2012. On March 26, 2012, the state judge granted respondent's motion to dismiss, based on the laches provision of O.C.G.A. § 9-14-48(e).6 Cole applied for a certificate of probable cause to appeal to the Georgia Supreme Court, which denied his application on November 19, 2012. Cole v. Upton, Warden, No. S12H1432 (Ga. Nov. 19, 2012).

On January 18, 2013, Cole filed a counseled federal habeas petition in the Northern District of Georgia under 28 U.S.C. § 2254. He pursued the same arguments he had presented in state court.7 Respondent moved to dismiss his habeas petition as untimely. Cole contended his petition was timely under 28 U.S.C. § 2244(d)(1)(D),8 because the statute of limitations is unconstitutional on the facts of his case, and he was entitled to equitable tolling.9 In his Final Report and Recommendation, the magistrate judge noted Cole had until April 24, 1997, to file his habeas petition. Cole, however, did not file his federal habeas petition "until January 18, 2013, more than fifteen years" after the limitations period had expired. Final Report & Recommendation at 4. While the magistrate judge rejected Cole's arguments for habeas relief, he recommended the district judge grant him a certificate of appealability ("COA"), regarding whether his petition was timely under § 2244(d)(1)(D) or amenable to equitable tolling.

In adopting the magistrate judge's Report and Recommendation, the district judge noted that Cole's objections relied on his contention he did not discover the factual predicate for his Boykin claim until September 2007. The judge concluded Cole's § 2254 petition was untimely under § 2244(d)(1)(D), because Cole knew the facts underlying his claims, when he pled guilty in 1991. "[A]lthough this conclusion appears harsh, the plain language of § 2244(d)(1)(D), which the Court is not free to ignore or change, requires it." Order Denying Habeas Relief at 15.

The district judge noted Cole based his equitable tolling argument on his age, when he pled guilty, and confinement, which he claims prevented him from discovering his Boykin rights earlier. He concluded the statutory limitations period did not commence when Cole discovered the alleged Boykin violation in September 2007. The judge recognized Cole had become an adult after his 1991 plea, and he could have used the prison law library to research his case before the statutory limitations period expired in 1997. He further determined that accepting Cole's unconstitutionality argument "would turn the one-year limitations period on its head." Id. at 25. Because he "was not reasonably diligent in discovering and pursuing the factual predicate of his claims," the judge also concluded Cole's case did "not present the extraordinary circumstances required to warrant equitable tolling." Id. at 21-22.

The district judge granted respondent's motion to dismiss Cole's § 2254 habeas petition. He also issued a COA for two issues: "(1) whether the § 2254 Petition is timely under 28 U.S.C. § 2244(d)(1)(D); and (2) if the § 2254 Petition is not timely under that provision, whether Petitioner is entitled to equitable tolling." Id. at 27. This appeal followed.

II. DISCUSSION

Cole argues he discovered the violation of his Boykin rights relative to § 2244(d)(1)(D) on an unspecified date in September 2007, when he overheard an inmate librarian discussing them. He contends both the judge, who took his guilty plea, and his counsel failed to advise him of his Boykin rights, precluding his knowledge of them and his ability to have waived them by pleading guilty. Alternatively, he seeks equitable tolling, based on his minority at his plea and incarceration thereafter.

A. Statutory Limitation and 28 U.S.C. § 2244(d)(1)(D)

With the "overriding purpose" of achieving finality in federal and state criminal cases, Congress enacted the Antiterrorism and Effective Death Penalty Act of 1996 ("AEDPA"), Pub.L. No. 104-132, 110 Stat. 1214 (1996). Murphy v. United States, 634 F.3d 1303, 1309 (11th Cir.2011). AEDPA establishes a one-year statute of limitations for a state prisoner to file a § 2254 habeas petition. 28 U.S.C. § 2244(d)(1). Since Cole's conviction became final before April 24, 1996, the effective date of AEDPA, he had until April 24, 1997, to file his federal habeas petition. Moore v. Campbell, 344 F.3d 1313, 1319-20 (11th Cir.2003) (per curiam). Cole did not file his § 2254 petition until January 18, 2013.

In keeping with its finality purpose, § 2244(d)(1) restricts a state prisoner's limitations period for filing a § 2254 habeas petition to one year, which begins to run "`from the latest of' four specified dates."10 Gonzalez v. Thaler, ___ U.S. ___, 132 S.Ct. 641, 652 & n. 9, 181 L.Ed.2d 619 (2012) (quoting 28 U.S.C. § 2244(d)(1)). The issue and subsection we address pursuant to the COA is whether Cole's one-year limitations period should have begun in September 2007, when he represents he discovered the alleged Boykin violations that occurred at his plea proceeding, which he argues is "the date on which the factual predicate of the claim or claims presented could have been discovered through the exercise of due diligence." 28 U.S.C. § 2244(d)(1)(D). We review de novo a district judge's dismissal of a habeas petition as time-barred under § 2244(d). Steed v. Head, 219 F.3d 1298, 1300 (11th Cir.2000). In contrast, our review of the judge's determination of relevant facts is for clear error. San Martin v. McNeil, 633 F.3d 1257, 1265 (11th Cir.2011).

In statutory construction, "[i]t is our duty to give effect, if possible, to every clause and word of a statute." Duncan v. Walker, 533 U.S. 167, 174, 121 S.Ct. 2120, 2125, 150 L.Ed.2d 251 (2001) (internal quotation marks omitted). "Section 2244(d)(1)(D) runs the [statute-of-limitations] clock from `the date on which the factual predicate of the claim ... could have been discovered through the exercise of due diligence.'" McQuiggin v. Perkins, ___ U.S. ___, 133 S.Ct. 1924, 1932, 185 L.Ed.2d 1019 (2013) (ellipsis in original). The analysis of "factual predicate" and "due diligence" in § 2244(d)(1)(D) is symbiotic. The factual predicate first must be determined to give meaning to due diligence in discovering the claim for a particular petitioner's case.

"[I]t should go without saying that a factual predicate must consist of facts. Conclusions drawn from preexisting facts, even if the conclusions are themselves new, are not factual predicates for a claim." Rivas v. Fischer, 687 F.3d 514, 535 (2d Cir.2012). The "factual predicate" also has been referenced as the underlying "vital facts" of a petitioner's claim. See, e.g., Ford v. Gonzalez, 683 F.3d 1230, 1235 (9th Cir.2012) ("The `due diligence' clock starts ticking when a person knows or through diligence could discover the vital facts, regardless of when their legal significance is actually discovered."); Mathena v. United States, 577 F.3d 943, 946 (8th Cir.2009) ("The factual predicate of a claim could have been discovered when a petitioner knows or should have known through due diligence the vital facts underlying the claim." (internal quotation marks omitted)); McAleese v. Brennan, 483 F.3d 206, 214 (3d Cir.2007) ("Though the AEDPA does not define `factual predicate,' we have held that section 2244(d)(1)(D) provides a petitioner with a later accrual date than section 2244(d)(1)(A) only if vital facts could not have been known." (second internal quotation marks and alteration omitted)); Owens v. Boyd, 235 F.3d 356, 359 (7th Cir.2000) ("Section 2244(d)(1)(D) gives defendants the benefit of a later start if vital facts could not have been known by the date the appellate process ended.").11

Comparing § 2244(d)(1)(D), applicable to state habeas prisoners, to 28 U.S.C. § 2255(f)(4),12 applicable to federal habeas prisoners, the Supreme Court has noted: "`Due diligence ... is an inexact measure of how much delay is too much.'" Walker v. Martin, ___ U.S. ___, 131 S.Ct. 1120, 1129, 179 L.Ed.2d 62 (2011) (alteration omitted) (quoting Johnson v. United States, 544 U.S. 295, 309, n. 7, 125 S.Ct. 1571, 1581, n. 7, 161 L.Ed.2d 542 (2005)). Therefore, the due diligence required of a state prisoner in filing a § 2254 habeas petition must be determined on a case-by-case basis relative to the factual predicate. The Seventh Circuit has decided an analogous case, because it involves two petitioners, who were serving state imprisonment sentences following guilty pleas and alleged they subsequently learned in prison they were subject to a three-year term of mandatory supervised release ("MSR"), defeating their plea bargains in violation of Santobello v. New York, 404 U.S. 257, 92 S.Ct. 495, 30 L.Ed.2d 427 (1971).13 Villanueva v. Anglin, 719 F.3d 769 (7th Cir. 2013). At each petitioner's plea proceeding, the judge told the petitioner he would have MSR following his imprisonment term; each still said he wanted to plead guilty. Id. at 771-72.

Villanueva's conviction became final on October 21, 2004; he allegedly learned of the MSR term from another inmate on December 15, 2006. Id. at 772. Serrano's conviction became final on July 5, 2002; he did not identify the date he learned of the MSR from a prison counselor. Id. Although petitioners filed their § 2254 habeas petitions "well outside" the one-year statute of limitations under § 2244(d)(1), they argued the statute of limitations should be tolled under § 2244(d)(1)(D), based on their subsequent learning of the MSR term while in prison. Id. at 774. The Seventh Circuit determined "due diligence is equivalent to a rule of inquiry notice," because the respective judges' warning petitioners at their plea proceedings they were subject to MSR "was all the notice they needed." Id. (internal quotation marks and alteration omitted). "Regardless of when Serrano and Villanueva assert they learned of the MSR requirement, they could have learned of it on the day they were sentenced had they used due diligence." Id. (emphasis added). Although the petitioners were not given the precise MSR term at sentencing, the Seventh Circuit noted "a reasonably diligent defendant would have, under the circumstances, asked the sentencing judge or his attorney about the mandatory term." Id. The court did not address the merits of the petitioners' claims, which were barred by the AEDPA statute of limitations.14 Id. at 774-75.

We conclude inquiry-notice analysis applies to Cole's contention he was deprived of being informed of his Boykin rights at his plea proceeding. While the transcript of his plea proceeding is not part of the record on appeal, see note 1, it does contain the written plea form Cole signed in the presence of his attorney. The Boykin rights to a jury trial, to confront his accusers, and not to incriminate himself together with his other constitutional rights are stated on the plea form Cole signed.15 Appendix (Guilty Plea, Apr. 1, 1991).

Cole has not represented that he cannot read or that he has a mental deficiency, which would have prevented him from understanding the plea form he signed in 1991. Therefore, he cannot say he was not informed of his Boykin rights at his plea proceeding. If he had questions about any rights he was relinquishing by pleading guilty as stated on the plea form, he could have consulted with his attorney at the time of his plea or before he signed the form. His signature verified he agreed and understood the rights he was foregoing by pleading guilty.

Consequently, Cole knew or should have known at the time of his plea the Boykin rights he claims he discovered in prison from an inmate librarian in September 2007. "Section 2244(d)(1)(D) follows the norm for a federal statute of limitations. Time begins when the prisoner knows (or through diligence could discover) the important facts, not when the prisoner recognizes their legal significance." Owens, 235 F.3d at 359 (emphasis added); see Brown v. Barrow, 512 F.3d 1304, 1307 (11th Cir.2008) (per curiam) (recognizing the AEDPA limitations period regarding § 2244(d)(1)(D) runs from the latest of "the date on which the factual predicate of the claim or claims presented could have been discovered through the exercise of due diligence" (emphasis added) (internal quotation marks omitted)); Schlueter v. Varner, 384 F.3d 69, 74 (3d Cir.2004) ("By its language, the one-year period of limitation commences under section 2244(d)(1)(D) when the factual predicate of a claim could have been discovered through the exercise of due diligence, not when it actually was discovered." (emphasis added)). Cole's § 2254 habeas petition is barred by inquiry notice evidencing lack of due diligence under § 2244(d)(1)(D) and AEDPA's one-year statute of limitations, which "quite plainly serves the well-recognized interest in the finality of state court judgments."16 Duncan, 533 U.S. at 179, 121 S.Ct. at 2128. The district judge correctly decided Cole's § 2254 petition was untimely under § 2244(d)(1)(D).

B. Equitable Tolling

Even if Cole's habeas petition was untimely under § 2244(d)(1)(D), he alternatively argues he is entitled to equitable tolling of the statutory filing date. Because "the time period specified in 28 U.S.C. § 2244 is a statute of limitations, not a jurisdictional bar," the Supreme Court has held § 2244(d) "does not bar the application of equitable tolling in an appropriate case." San Martin, 633 F.3d at 1267 (citing Holland v. Florida, 560 U.S. 631, 645, 130 S.Ct. 2549, 2560, 177 L.Ed.2d 130 (2010)). "[A] petitioner is entitled to equitable tolling only if he shows (1) that he has been pursuing his rights diligently, and (2) that some extraordinary circumstance stood in his way and prevented timely filing." Holland, 560 U.S. at 649, 130 S.Ct. at 2562 (internal quotation marks omitted). As an extraordinary remedy, equitable tolling is "limited to rare and exceptional circumstances and typically applied sparingly."17 Cadet v. Fla. Dep't of Corr., 742 F.3d 473, 477 (11th Cir.2014) (internal quotation marks omitted).

While we review de novo a district judge's decision to deny equitable tolling for a § 2254 petition, we review relevant factual determinations for clear error. San Martin, 633 F.3d at 1265. Equitable tolling is assessed on a case-by-case basis, considering the specific circumstances of the subject case. Hutchinson v. Florida, 677 F.3d 1097, 1098 (11th Cir.2012); see Holland, 560 U.S. at 649-50, 130 S.Ct. at 2563 (clarifying "the exercise of a court's equity powers must be made on a case-by-case basis" (internal quotation marks and ellipsis omitted)). The petitioner has the burden of establishing his entitlement to equitable tolling; his supporting allegations must be specific and not conclusory. Hutchinson, 677 F.3d at 1099. "The diligence required for equitable tolling purposes is reasonable diligence, not maximum feasible diligence." Holland, 560 U.S. at 653, 130 S.Ct. at 2565 (internal citation and quotation marks omitted); see Smith v. Comm'r, Ala. Dep't of Corr., 703 F.3d 1266, 1271 (11th Cir.2012) (per curiam) (acknowledging petitioners are not required "to exhaust every imaginable option, but rather to make reasonable efforts" (internal quotation marks omitted)). Determining whether a factual circumstance is extraordinary to satisfy equitable tolling depends not on "how unusual the circumstance alleged to warrant tolling is among the universe of prisoners, but rather how severe an obstacle it is for the prisoner endeavoring to comply with AEDPA's limitations period." Diaz v. Kelly, 515 F.3d 149, 154 (2d Cir.2008). A habeas petitioner is not entitled to equitable tolling simply because he alleges constitutional violations at his trial or sentencing. Gibson v. Klinger, 232 F.3d 799, 808 (10th Cir.2000).

Cole has failed to show learning of his Boykin rights from an overheard conversation of an inmate librarian was an extraordinary circumstance warranting equitable tolling for his delayed filing of his habeas petition for more than fifteen years from the expiration of his AEDPA statute of limitations. He has not demonstrated he exercised reasonable diligence in pursuing discovery of his Boykin rights, when he had signed the plea form stating these rights at his plea proceeding. Consequently, he has not manifested a nexus between his alleged extraordinary circumstance and the late filing of his § 2254 petition, required for equitable tolling. See San Martin, 633 F.3d at 1270-71. Cole has made no new factual arguments in his § 2254 petition to support equitable tolling as his alternative basis permitting him until September 2007 from which to count his one-year period for filing his habeas petition.18 "Recharacterizing [petitioner's] argument as a request for `equitable tolling' adds nothing; § 2244(d)(1)(D) is itself a kind of tolling rule, and it would be inappropriate for the judiciary to add time on a theory that would amount to little more than disagreement with the way Congress wrote § 2244(d)." Owens, 235 F.3d at 360 (citation omitted). The district judge did not clearly err in determining Cole was not entitled to equitable tolling on these facts and dismissing his habeas petition on that basis.

AFFIRMED.

APPENDIX