ILCS » Chapter 815 · Act 205
Illinois Compiled Statutes

815 ILCS 205/10 (2026)

In all computations of time, and of interest and discounts, a month shall be considered to mean a calendar month, and a year shall consist of twelve calendar months; and in computations of interest or discount for any number of days less than a month, a day shall be considered a thirtieth part of a month, and interest or discount shall be computed for such fractional parts of a month upon the ratio which such number of days shall bear to thirty

✓ laws through the 2026 session (checked Sept. 2026)
Find cases: SyfertCases citing this section IL-ILGAilga.gov JustiaChapter on Justia CornellLII Search CasesGoogle Scholar
(815 ILCS 205/10) (from Ch. 17, par. 6418)
    Sec. 10. In all computations of time, and of interest and discounts, a month shall be considered to mean a calendar month, and a year shall consist of twelve calendar months; and in computations of interest or discount for any number of days less than a month, a day shall be considered a thirtieth part of a month, and interest or discount shall be computed for such fractional parts of a month upon the ratio which such number of days shall bear to thirty.
(Source: Laws 1879, p. 184.)

    
Notes of Decisions
Cited in 6 cases (1 in the last 5 years), 1994–2023 · leading case: Halloran v. Dickerson, 679 N.E.2d 774 (Ill. App. Ct. 5th Dist. 1997).
Sort: Relevance Newest Treatment
Halloran v. Dickerson, 679 N.E.2d 774 (Ill. App. Ct. 5th Dist. 1997). · cites it 2× “Illinois law provides: "In all computations of time, and of interest and discounts, a month shall be considered to mean a calendar month, and a year shall consist of twelve calendar months; and in computations of interest or discount for any number of days less than a month, a…”
Hubbard Street Lofts LLC v. Inland Bank, 963 N.E.2d 262 (Ill. App. Ct. 1st Dist. 2011). “" 815 ILCS 205/10 (West 2010). Section 16 of the Promissory Note Act, also cited by Hubbard Street Lofts, is identical to section 10 of the Interest Act.”
In re Marriage of Bonzani, 2023 IL App (3d) 220026-U. “3d 857, 863 (1997) (“It is well-established in Illinois that *** accrual of interest [under section 10 of the Interest Act (815 ILCS 205/10 (West 1992)] is simple interest and not compound interest.”
Hubbard Street Lofts v. Inland Bank, 2011 IL App (1st) 102640. “” 815 ILCS 205/10 (West 2010). Section 16 of the Promissory Note Act, also cited by Hubbard Street Lofts, is identical to section 10 of the Interest Act.”
Unique Envelope Corp. v. GS Am., Inc., 331 F. Supp. 2d 643 (N.D. Ill. 2004). “As a result of this breach, Unique has been damaged in the amount of $239,936.54 and Unique is entitled to prejudgment interest at a rate of five percent from January 10, 1999, through entry of judgment, 815 ILCS 205/2, which, at 5% is $11,996.”
Ge Capital Asset Mgmt. Corp. v. La Porta, 256 Ill. App. 3d 546 (Ill. App. Ct. 2d Dist. 1994). “(See 815 ILCS 205/10 (West 1992).) According to the defendant, because of GE Capital’s predecessor’s illegal interest assessments, the usual exemption for depository institutions from the State’s usury laws (see 205 ILCS 105/5 — 10 (West 1992)) is not due to GE Capital, and…”
Annotations are extracted automatically from the opinions in the Syfert caselaw corpus and ranked by authority, recency, and treatment. Dots show Syfertize treatment of the citing case itself.