Internal Revenue Code · 26 U.S.C.
§ 6601. Interest on underpayment, nonpayment, or extensions of time for payment, of tax
Official text, no changes From the Office of the Law Revision Counsel, release point 119-121 (current through Public Law 119-121 (October 9, 2026)). Compare it with the official text at uscode.house.gov (external site).
Cite as 26 U.S.C. § 6601
At a glance
Read from the text, the source credit and the official notes. Not part of the law.
- Status
- In force
- Enacted
- September 2, 1958 by Pub. L. 85–866
- Last amended
- March 23, 2018 by Pub. L. 115–141
- Amendments
- 30 dated changes in the source credit
- Length
- 11 subsections · 2,270 words · about 10 min to read
- Defines
- 3 terms
- Cross-references
- cites 16; cited by 18 Code sections and 47 other regulations
- Regulations
- 4 issued under this section
If any amount of tax imposed by this title (whether required to be shown on a return, or to be paid by stamp or by some other method) is not paid on or before the last date prescribed for payment, interest on such amount at the underpayment rate established under section 6621 shall be paid for the period from such last date to the date paid.
The last date prescribed for payment shall be determined without regard to any extension of time for payment or any installment agreement entered into under section 6159.
The last date prescribed for payment shall be determined without regard to any notice and demand for payment issued, by reason of jeopardy (as provided in chapter 70), prior to the last date otherwise prescribed for such payment.
In the case of the tax imposed by section 531 for any taxable year, the last date prescribed for payment shall be deemed to be the due date (without regard to extensions) for the return of tax imposed by subtitle A for such taxable year.
In the case of taxes payable by stamp and in all other cases in which the last date for payment is not otherwise prescribed, the last date for payment shall be deemed to be the date the liability for tax arises (and in no event shall be later than the date notice and demand for the tax is made by the Secretary).
In the case of a deficiency as defined in section 6211 (relating to income, estate, gift, and certain excise taxes), if a waiver of restrictions under section 6213(d) on the assessment of such deficiency has been filed, and if notice and demand by the Secretary for payment of such deficiency is not made within 30 days after the filing of such waiver, interest shall not be imposed on such deficiency for the period beginning immediately after such 30th day and ending with the date of notice and demand and interest shall not be imposed during such period on any interest with respect to such deficiency for any prior period.
If the amount of any tax imposed by subtitle A is reduced by reason of a carryback of a net operating loss or net capital loss, such reduction in tax shall not affect the computation of interest under this section for the period ending with the filing date for the taxable year in which the net operating loss or net capital loss arises.
If any credit allowed for any taxable year is increased by reason of a carryback of tax paid or accrued to foreign countries or possessions of the United States, such increase shall not affect the computation of interest under this section for the period ending with the filing date for the taxable year in which such taxes were in fact paid or accrued, or, with respect to any portion of such credit carryback from a taxable year attributable to a net operating loss carryback or a capital loss carryback from a subsequent taxable year, such increase shall not affect the computation of interest under this section for the period ending with the filing date for such subsequent taxable year.
If any credit allowed for any taxable year is increased by reason of a credit carryback, such increase shall not affect the computation of interest under this section for the period ending with the filing date for the taxable year in which the credit carryback arises, or, with respect to any portion of a credit carryback from a taxable year attributable to a net operating loss carryback, capital loss carryback, or other credit carryback from a subsequent taxable year, such increase shall not affect the computation of interest under this section for the period ending with the filing date for such subsequent taxable year.
For purposes of this paragraph, the term “credit carryback” has the meaning given such term by section 6511(d)(4)(C).
For purposes of this subsection, the term “filing date” has the meaning given to such term by section 6611(f)(4)(A).
Interest prescribed under this section on any tax shall be paid upon notice and demand, and shall be assessed, collected, and paid in the same manner as taxes. Any reference to this title (except subchapter B of chapter 63, relating to deficiency procedures) to any tax imposed by this title shall be deemed also to refer to interest imposed by this section on such tax.
Interest shall be imposed under subsection (a) in respect of any assessable penalty, additional amount, or addition to the tax (other than an addition to tax imposed under section 6651(a)(1) or 6653 or under part II of subchapter A of chapter 68) only if such assessable penalty, additional amount, or addition to the tax is not paid within 21 calendar days from the date of notice and demand therefor (10 business days if the amount for which such notice and demand is made equals or exceeds $100,000), and in such case interest shall be imposed only for the period from the date of the notice and demand to the date of payment.
If notice and demand is made for payment of any amount and if such amount is paid within 21 calendar days (10 business days if the amount for which such notice and demand is made equals or exceeds $100,000) after the date of such notice and demand, interest under this section on the amount so paid shall not be imposed for the period after the date of such notice and demand.
If any portion of a tax is satisfied by credit of an overpayment, then no interest shall be imposed under this section on the portion of the tax so satisfied for any period during which, if the credit had not been made, interest would have been allowable with respect to such overpayment. The preceding sentence shall not apply to the extent that section 6621(d) applies.
Interest prescribed under this section on any tax may be assessed and collected at any time during the period within which the tax to which such interest relates may be collected.
This section shall not apply to any failure to pay any estimated tax required to be paid by section 6654 or 6655.
This section shall not apply to any failure to make a payment of tax imposed by section 3301 for a calendar quarter or other period within a taxable year required under authority of section 6157.
If the amount of tax imposed by chapter 11 which is extended as provided in section 6166 exceeds the 2-percent portion, any payment of a portion of such amount shall, for purposes of computing interest for periods after such payment, be treated as reducing the 2-percent portion by an amount which bears the same ratio to the amount of such payment as the amount of the 2-percent portion (determined without regard to this paragraph) bears to the amount of the tax which is extended as provided in section 6166.
For provisions prohibiting interest on certain adjustments in tax, see section 6205(a).
(Aug. 16, 1954, ch. 736, 68A Stat. 817; Pub. L. 85–866, title I, §§ 66(c), 83(a)(1), 84(a), title II, § 206(e), Sept. 2, 1958, 72 Stat. 1658, 1663, 1664, 1685; Pub. L. 87–61, title II, § 203(c)(2), June 29, 1961, 75 Stat. 126; Pub. L. 87–834, § 2(e)(3), Oct. 16, 1962, 76 Stat. 972; Pub. L. 88–571, § 3(d), Sept. 2, 1964, 78 Stat. 858; Pub. L. 89–384, § 1(f), Apr. 8, 1966, 80 Stat. 104; Pub. L. 90–225, § 2(e), Dec. 27, 1967, 81 Stat. 731; Pub. L. 91–53, § 2(e), Aug. 7, 1969, 83 Stat. 92; Pub. L. 91–172, title I, § 101(j)(49), title V, § 512(e)(3), Dec. 30, 1969, 83 Stat. 531, 641; Pub. L. 92–178, title VI, § 601(d)(3), Dec. 10, 1971, 85 Stat. 559; Pub. L. 93–406, title II, § 1016(a)(17), Sept. 2, 1974, 88 Stat. 930; Pub. L. 93–625, § 7(a)(2)(A), (b)(1), Jan. 3, 1975, 88 Stat. 2115; Pub. L. 94–452, § 3(c)(3), Oct. 2, 1976, 90 Stat. 1514; Pub. L. 94–455, title XIII, § 1307(d)(2)(H), title XVI, § 1605(b)(10), title XIX, §§ 1906(a)(34), (b)(13)(A), title XX, § 2004(b), title XXI, § 2107(g)(2)(C), Oct. 4, 1976, 90 Stat. 1728, 1755, 1829, 1834, 1867, 1904; Pub. L. 95–30, title II, § 202(d)(4)(C), May 23, 1977, 91 Stat. 150; Pub. L. 95–628, § 8(c)(2), Nov. 10, 1978, 92 Stat. 3632; Pub. L. 96–223, title I, § 101(f)(7), Apr. 2, 1980, 94 Stat. 253; Pub. L. 97–248, title III, §§ 344(b)(1), 346(c)(2), Sept. 3, 1982, 96 Stat. 635, 637; Pub. L. 98–76, title II, § 231(b)(2)(D), Aug. 12, 1983, 97 Stat. 429; Pub. L. 98–369, div. A, title I, § 158(a), title II, § 211(b)(26), title IV, § 412(b)(7), title VII, § 714(n)(1), July 18, 1984, 98 Stat. 696, 757, 792, 963; Pub. L. 99–514, title XIV, § 1404(c)(3), title XV, §§ 1511(c)(11), 1512(a), 1564(a), Oct. 22, 1986, 100 Stat. 2714, 2745, 2746, 2762; Pub. L. 100–203, title X, § 10301(b)(5), Dec. 22, 1987, 101 Stat. 1330–429; Pub. L. 100–647, title I, §§ 1015(b)(2)(C), 1018(u)(42), title VI, § 6234(b)(1), title VII, § 7106(c)(5), Nov. 10, 1988, 102 Stat. 3569, 3592, 3736, 3774; Pub. L. 101–239, title VII, § 7721(c)(8), Dec. 19, 1989, 103 Stat. 2400; Pub. L. 101–508, title XI, § 11801(c)(20)(B), Nov. 5, 1990, 104 Stat. 1388–528; Pub. L. 104–168, title III, § 303(a), (b)(1), July 30, 1996, 110 Stat. 1458; Pub. L. 105–34, title V, §§ 501(e), 503(a), (c)(2), (3), title X, § 1055(a), title XII, § 1242(a), Aug. 5, 1997, 111 Stat. 846, 852, 853, 944, 1029; Pub. L. 105–206, title III, § 3301(b), July 22, 1998, 112 Stat. 741; Pub. L. 109–135, title IV, § 409(a)(2), Dec. 21, 2005, 119 Stat. 2635; Pub. L. 114–74, title XI, § 1101(f)(9), Nov. 2, 2015, 129 Stat. 638; Pub. L. 115–97, title I, § 11002(d)(1)(JJ), Dec. 22, 2017, 131 Stat. 2060; Pub. L. 115–141, div. U, title IV, § 401(b)(47), Mar. 23, 2018, 132 Stat. 1204.)
Terms defined here
Where the text says “the term … means”. Select a term to jump to its definition.
Regulations under this section
Treasury regulations (26 CFR) issued under § 6601
- § 20.6601-1 Interest on underpayment, nonpayment, or extensions of time for payment, of tax.
- § 25.6601-1 Interest on underpayment, nonpayment, or extensions of time for payment, of tax.
- § 53.6601-1 Interest on underpayment, nonpayment, or extensions of time for payment, of tax.
- § 301.6601-1 Interest on underpayments.
Cross-references
Computed from the citations in the text of Title 26 and 26 CFR.
This section cites 16 other sections
- § 6621 Determination of rate of interest
- § 6159 Agreements for payment of tax liability in installments
- § 531 Imposition of accumulated earnings tax
- § 6211 Definition of a deficiency
- § 6213(d) Restrictions applicable to deficiencies; petition to Tax Court
- § 6511(d)(4)(C) Limitations on credit or refund
- § 6611(f)(4)(A) Interest on overpayments
- § 6651(a)(1) Failure to file tax return or to pay tax
- § 6654 Failure by individual to pay estimated income tax
- § 3301 Rate of tax
- § 6157 Payment of Federal unemployment tax on quarterly or other time period basis
- § 6166 Extension of time for payment of estate tax where estate consists largely of interest in closely held business
- § 2001(c) Imposition and rate of tax
- § 2010(c) Unified credit against estate tax
- § 1(f)(3) Tax imposed
- § 6205(a) Special rules applicable to certain employment taxes
Cited by 18 Code sections
- § 163(h)(2)(E) Interest
- § 860(c)(1)(B) Deduction for deficiency dividends
- § 877A(b)(7) Tax responsibilities of expatriation
- § 995(f)(6) Taxation of DISC income to shareholders
- § 1016(c)(5)(B) Adjustments to basis
- § 1260(b)(2) Gains from constructive ownership transactions
- § 1291(c)(1)(B) Interest on tax deferral
- § 1294(g) Election to extend time for payment of tax on undistributed earnings
- § 1363(d)(2)(C) Effect of election on corporation
- § 2053(c)(1)(D) Expenses, indebtedness, and taxes
- § 5684(c)(1) Penalties relating to the payment and collection of liquor taxes
- § 6166(b)(7)(A)(iii) Extension of time for payment of estate tax where estate consists largely of interest in closely held business
- § 6167(e) Extension of time for payment of tax attributable to recovery of foreign expropriation losses
- § 6504(9) Cross references
- § 6603(b) Deposits made to suspend running of interest on potential underpayments, etc.
- § 6621(c)(1) Determination of rate of interest
- § 7404 Authority to bring civil action for estate taxes
- § 7518(g)(3)(C)(i) Tax incentives relating to merchant marine capital construction funds
Cited in 47 regulations not issued under it
- § 1.163-9T Personal interest (temporary).
- § 1.460-6 Look-back method.
- § 1.468B-5 Effective dates and transition rules applicable to qualified settlement funds.
- § 1.507-2 Special rules; transfer to, or operation as, public charity.
- § 1.860-3 Interest and additions to tax.
- § 1.905-4 Notification of foreign tax redetermination.
- § 1.936-6 Intangible property income when an election out is made: Cost sharing and profit split options; covered intangibles.
- § 1.1291-9 Deemed dividend election.
- § 1.1291-10 Deemed sale election.
- § 1.1294-1T Election to extend the time for payment of tax on undistributed earnings of a qualified electing fund (temporary).
- § 1.1297-3 Deemed sale or deemed dividend election by a U.S. person that is a shareholder of a section 1297(e) PFIC.
- § 1.1298-3 Deemed sale or deemed dividend election by a U.S. person that is a shareholder of a former PFIC.
- § 1.1402(f)-1 Computation of partner's net earnings from self-employment for taxable year which ends as result of his death.
- § 1.1441-1 Requirement for the deduction and withholding of tax on payments to foreign persons.
- § 1.1445-1 Withholding on dispositions of U.S. real property interests by foreign persons: In general.
- § 1.1446-3 Time and manner of calculating and paying over the 1446 tax.
- § 1.1446-6 Special rules to reduce a partnership's 1446 tax with respect to a foreign partner's allocable share of effectively connected taxable income.
- § 1.1446(f)-3 Partnership's requirement to withhold under section 1446(f)(4) on distributions to transferee.
- § 1.1461-3 Withholding under section 1446.
- § 1.1503(d)-6 Exceptions to the domestic use limitation rule.
- § 1.6161-1 Extension of time for paying tax or deficiency.
- § 1.6164-9 Cross references.
- § 1.6696-1 Claims for credit or refund by tax return preparers or appraisers.
- § 1.9002 Statutory provisions; Dealer Reserve Income Adjustment Act of 1960 (74 Stat. 124).
Show 23 more
- § 1.9002-4 Election to pay net increase in tax in installments.
- § 1.9002-5 Special rules relating to interest.
- § 1.9006 Statutory provisions; Tax Reform Act of 1969.
- § 1.9006-1 Interest and penalties in case of certain taxable years.
- § 3.0 Statutory provisions; section 607, Merchant Marine Act, 1936, as amended.
- § 3.7 Tax treatment of nonqualified withdrawals.
- § 20.6163-1 Extension of time for payment of estate tax on value of reversionary or remainder interest in property.
- § 20.6166-1 Election of alternate extension of time for payment of estate tax where estate consists largely of interest in closely held business.
- § 20.6166A-1 Extension of time for payment of estate tax where estate consists largely of interest in closely held business.
- § 20.6324A-1 Special lien for estate tax deferred under section 6166 or 6166A.
- § 25.6161-1 Extension of time for paying tax or deficiency.
- § 31.6205-1 Adjustments of underpayments.
- § 31.6205-2 Adjustments of underpayments of hospital insurance taxes that accrue after March 31, 1986, and before January 1, 1987, with respect to wages of State and local government employees.
- § 32.1 Social security taxes with respect to payments on account of sickness or accident disability.
- § 32.2 Railroad retirement taxes with respect to payments on account of sickness or accident disability.
- § 51.5 Fee calculation.
- § 53.6161-1 Extension of time for paying tax or deficiency.
- § 301.6159-1 Agreements for payment of tax liabilities in installments.
- § 301.6621-1 Interest rate.
- § 301.6621-2T Questions and answers relating to the increased rate of interest on substantial underpayments attributable to certain tax motivated transactions (temporary).
- § 301.6621-3 Higher interest rate payable on large corporate underpayments.
- § 301.6873-1 Unpaid claims in bankruptcy or receivership proceedings.
- § 301.9100-6T Time and manner of making certain elections under the Deficit Reduction Act of 1984.
Amendment history
From the source credit and the official notes, newest first.
- Amended by Pub. L. 115–141Parts changed in 2018: (b)(2)
- Amended by Pub. L. 115–97Parts changed in 2017: (j)(3)(B)
- Amended by Pub. L. 114–74Parts changed in 2015: (c)
- Amended by Pub. L. 109–135Parts changed in 2005: (d)(4)
- Amended by Pub. L. 105–206Parts changed in 1998: (f)
- Amended by Pub. L. 105–34Parts changed in 1997: (c) (d)(2) (j) (j)(1) (j)(2) (j)(3) (j)(4)
- Amended by Pub. L. 104–168Parts changed in 1996: (e)(2)(A) (e)(3)
- Amended by Pub. L. 101–508Parts changed in 1990: (b)(2)
- Amended by Pub. L. 101–239Parts changed in 1989: (e)(2)
- Amended by Pub. L. 100–647Parts changed in 1988: (b)(1) (b)(2) (e)(2)(A) (i)
- Amended by Pub. L. 100–203Parts changed in 1987: (h)
- Amended by Pub. L. 99–514Parts changed in 1986: (a) (b)(2) (b)(4) (c)
- Amended by Pub. L. 98–369Parts changed in 1984: (d)(2)(A) (d)(3) (e)(2) (h)
- Amended by Pub. L. 98–76Parts changed in 1983: (i)
- Amended by Pub. L. 97–248Parts changed in 1982: (d)(1) (d)(2)(A) (d)(4) (e)
- Amended by Pub. L. 96–223Parts changed in 1980: (c)
- Amended by Pub. L. 95–628Parts changed in 1978: (d)(2) (d)(4)
- Amended by Pub. L. 95–30Parts changed in 1977: (d)(5)
- Amended by Pub. L. 94–455Parts changed in 1976: (b)(2) (b)(4) (c) (d)(4) (h) (j)
- Amended by Pub. L. 94–452
- Amended by Pub. L. 93–625Parts changed in 1975: (a) (b)
- Amended by Pub. L. 93–406Parts changed in 1974: (d)
- Amended by Pub. L. 92–178Parts changed in 1971: (e)(4)
- Amended by Pub. L. 91–172Parts changed in 1969: (d) (e)(1) (e)(2) (k)
- Amended by Pub. L. 91–53
- Amended by Pub. L. 90–225Parts changed in 1967: (e)(2)
- Amended by Pub. L. 89–384Parts changed in 1966: (j)
- Amended by Pub. L. 88–571Parts changed in 1964: (e)
- Amended by Pub. L. 87–834Parts changed in 1962: (e)
- Amended by Pub. L. 87–61Parts changed in 1961: (c)(2)
- Enacted by Pub. L. 85–866Parts changed in 1958: (b) (g)
Where it sits in the Code
Nearby sections
- § 6601 Interest on underpayment, nonpayment, or extensions of time for payment, of tax
- § 6602 Interest on erroneous refund recoverable by suit
- § 6603 Deposits made to suspend running of interest on potential underpayments, etc.
Official notes
The Law Revision Counsel's notes for this section (amendments, effective dates and related laws) are long, so they have their own page.