US federal tax constants, tax year 2026
United States federal law · tax year 2026 · open data under CC0
Thirty-six constants that decide what a self-employed person in the United States owes for 2026 — each one with the IRS, SSA or statutory document it was read from, and the date it was read.
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36 constants, every one verified against a primary document. Last verified 2026-08-25.
Model self-check: 529 assertions passed, 0 failed
Licence: CC0 1.0 — CC0 1.0 Universal (public domain dedication)
These are the numbers any US tax calculator needs before it can compute anything: the seven rate-schedule brackets for each filing status, the standard deduction, the self-employment tax rates and the wage base they stop at, the section 199A thresholds, the safe-harbour percentages, the four payment dates, both 2026 mileage rates and the Form 1099-K reporting thresholds. They are scattered across a revenue procedure, three IRS forms, a publication, two Internal Revenue Bulletin items, a statute and an actuarial page at the Social Security Administration.
We had to assemble them to build our own tax workbook. Rather than keep the table, we publish it: free, machine-readable, and carrying its own sources.
How every figure was verified
Each value was read out of the primary document itself — the revenue procedure, the form, the publication, the statute or the actuarial page — never from a summary, a blog post or a secondary table. The date in the last column is the day that document was actually retrieved and read.
The two models that hold the table test themselves against hand-worked examples on every build, and refuse to produce anything at all if a constant lacks its source, its URL, its verification date, or its verified status. The files offered above are written by that build, so an unverified figure cannot reach them.
Many rows also carry a cross-check: where two documents print the same figure, both are named, and where a number that circulates widely is wrong for 2026, the note says so and gives the right one.
Licence: CC0 1.0
This table is dedicated to the public domain under CC0 1.0. Tax constants are facts taken from United States federal law and from US government publications: facts cannot be copyrighted, and works of the US federal government carry no copyright either.
CC0 removes any lingering doubt about the compilation itself, so anyone may copy it into a spreadsheet, a database or a product without asking. A link back is welcome, but it is not a condition of use.
What this does not cover
United States federal law only, and only tax year 2026. No state or city tax, no tax credits, no employer payroll filing, nothing for any other year. It is a reference table, not tax advice — check any figure against the linked document before you rely on it.
- State and city income tax of any kind. This is United States federal law only.
- Tax credits — earned income, child, education, premium tax credit and every other credit.
- Payroll tax as an employer files it (Forms 941/940), and W-2 withholding tables.
- Corporate, partnership and S-corporation returns; anything that is not an individual return with self-employment income.
- Any tax year other than 2026, and any tax act passed after the verification date above.
- Platform selling fees, which drift constantly and are not law. They are not part of this dataset.
The constants
The table itself stays in English: it is a United States federal reference and every source document is written in English.
Each note is reproduced verbatim from the model that holds the constant — cross-checks, the exact form line, the sentence quoted from the source. Where a note says “the brief”, it means the internal specification these models were written against: in two places that specification carried a figure that turned out to be the 2025 one, and the note records the correction and the document it came from.
Ordinary income tax rate schedules 1
The seven 2026 brackets, per filing status. Expanded in full in the JSON file and further down this page.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
ordinary_brackets_2026 |
7 brackets 10/12/22/24/32/35/37 for single, mfj, mfs, hoh (see BRACKETS) | indexed | Rev. Proc. 2025-32 (2026 inflation adjustments; announced in IR-2025-103), section 4.01 / 4.14 / 4.26, TABLES 1-4 cross-checked against the 2026 Tax Rate Schedules in Pub. 505 (2026) p.31; identical | ✓ verified |
Standard deduction 1
The 2026 basic standard deduction by filing status.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
standard_deduction_2026 |
mfj/qss 32200, hoh 24150, single 16100, mfs 16100 | indexed | Rev. Proc. 2025-32 (2026 inflation adjustments; announced in IR-2025-103), section 4.01 / 4.14 / 4.26 sec. 4.14(1) also printed in Form 1040-ES (2026) p.2 chart; identical | ✓ verified |
Self-employment tax (Schedule SE, Form 8959) 8
The rates, the 92.35% factor, the $400 floor, the social security wage base and the Additional Medicare Tax thresholds.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
additional_medicare_rate |
0.009 | statutory | Form 8959, Additional Medicare Tax, rev. 2025 — the latest revision published, lines 7/13 also IRS Tax Topic 560, Additional Medicare Tax at https://www.irs.gov/taxtopics/tc560 | ✓ verified |
additional_medicare_thresholds |
mfj 250000, mfs 125000, single/hoh/qss 200000 | statutory | Form 8959, Additional Medicare Tax, rev. 2025 — the latest revision published, lines 5/9/15 also Pub. 505 (2026) p.27 table; statutory under IRC 1401(b)(2)(A), NOT indexed | ✓ verified |
medicare_rate |
0.029 | statutory | Schedule SE (Form 1040), rev. 2025 — the latest revision published, line 11 | ✓ verified |
oasdi_rate |
0.124 | statutory | Schedule SE (Form 1040), rev. 2025 — the latest revision published, line 10 | ✓ verified |
se_deductible_half |
0.50 | statutory | Schedule SE (Form 1040), rev. 2025 — the latest revision published, line 13 deduction is 50% of Sch SE line 12 and therefore excludes Additional Medicare Tax, which is not on Schedule SE | ✓ verified |
se_minimum |
400 | statutory | Schedule SE (Form 1040), rev. 2025 — the latest revision published, line 4c | ✓ verified |
se_net_earnings_factor |
0.9235 | statutory | Schedule SE (Form 1040), rev. 2025 — the latest revision published, Part I line 4a also Instructions for Form 2210 (2025), Schedule AI Line 28 | ✓ verified |
ss_wage_base_2026 |
184500 | indexed | SSA Office of the Chief Actuary, Contribution and benefit bases, 1937-2026 determination shown at https://www.ssa.gov/oact/cola/cbbdet.html ($60,600 x 69,846.57 / 22,935.42 = $184,548.71, rounded to nearest $300). Independently confirmed by Pub. 505 (2026) Worksheet 2-9 line 34 col (d) = $184,500. 2025 was $176,100. | ✓ verified |
Qualified business income deduction (section 199A) 7
Thresholds and phase-in ranges as adjusted for 2026, plus the two new minimum-deduction rules added by OBBBA sec. 70105(b).
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
qbi_minimum_deduction |
400 | indexed-from-2027 | 26 U.S.C. 199A as amended by P.L. 119-21 (OBBBA) sec. 70105 subsec. (i)(1)(B) PRIMARY SOURCE, not a secondary one. Corroborated by Rev. Proc. 2025-32 sec. 3.12 and by Form 1040-ES (2026) p.2 'Changes to QBID'. Not indexed until 2027. | ✓ verified |
qbi_minimum_qbi_test |
1000, and the statutory test is 'AT LEAST $1,000', not 'exceeds $1,000' | indexed-from-2027 | 26 U.S.C. 199A as amended by P.L. 119-21 (OBBBA) sec. 70105 subsec. (i)(2)(A) aggregate QBI across all ACTIVE qualified trades or businesses (material participation, IRC 469(h)) | ✓ verified |
qbi_phasein_top_2026 |
mfj 553500, mfs 276775, all others 276750 | indexed | Rev. Proc. 2025-32 (2026 inflation adjustments; announced in IR-2025-103), section 4.01 / 4.14 / 4.26 sec. 4.26 ('Phase-in range amount') equals threshold + 150000 (joint) / + 75000 (all others), matching IRC 199A(b)(3)(B)(ii)(II) and 199A(d)(3)(B)(ii) as amended by OBBBA sec. 70105(a). The brief's reported 544,600 is wrong. | ✓ verified |
qbi_phasein_width |
75000 (150000 joint) | statutory | 26 U.S.C. 199A as amended by P.L. 119-21 (OBBBA) sec. 70105 subsecs. (b)(3)(B)(ii)(II), (d)(3)(B)(ii) statute read directly; OBBBA substituted these for 50000/100000 | ✓ verified |
qbi_rate |
0.20 | statutory | Form 8995-A (2025) line 3 / IRC 199A(a) | ✓ verified |
qbi_reduced_by_half_se |
QBI is reduced by the deductible part of self-employment tax | structural | Instructions for Form 8995-A (2025), 'Determining Your Qualified Business Income' 'This includes, but isn't limited to, unreimbursed partnership expenses, business interest expense, deductible part of self-employment tax, self-employment health insurance deduction, and contributions to qualified retirement plans.' | ✓ verified |
qbi_thresholds_2026 |
mfj 403500, mfs 201775, all others 201750 | indexed | Rev. Proc. 2025-32 (2026 inflation adjustments; announced in IR-2025-103), section 4.01 / 4.14 / 4.26 sec. 4.26 THE TASK BRIEF'S REPORTED 394,600 IS WRONG FOR 2026 — that is the 2025 MFJ threshold, printed on the 2025 Form 8995-A. | ✓ verified |
Estimated tax: the safe-harbour tests and the due dates 6
Form 1040-ES General Rule percentages, the high-income threshold, the $1,000 de minimis and the four 2026 payment dates.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
due_dates_2026 |
2026-04-15, 2026-06-15, 2026-09-15, 2027-01-15 | structural | Form 1040-ES (2026), Estimated Tax for Individuals, 'Payment Due Dates' p.4 also Pub. 505 (2026) Table 2-1. None of the four falls on a weekend or DC legal holiday in 2026, so no shift applies this year. | ✓ verified |
est_100_pct_prior_year |
1.00 | statutory | Form 1040-ES (2026), Estimated Tax for Individuals, General Rule 2b prior-year return must cover all 12 months | ✓ verified |
est_110_pct_high_agi |
1.10 where 2025 AGI > 150000 (75000 if 2026 status is MFS) | statutory | Form 1040-ES (2026), Estimated Tax for Individuals, 'Higher income taxpayers' also Pub. 505 (2026) 'Required Annual Payment - Line 12c' | ✓ verified |
est_90_pct_current_year |
0.90 | statutory | Form 1040-ES (2026), Estimated Tax for Individuals, General Rule 2a | ✓ verified |
est_de_minimis |
1000 | statutory | Form 1040-ES (2026), Estimated Tax for Individuals, General Rule 1 Pub. 505 WS 2-1 line 14b applies it to total tax MINUS withholding, i.e. line 11c - line 13, NOT to line 12c | ✓ verified |
weekend_holiday_shift_rule |
if a due date falls on a Saturday, Sunday, or legal holiday, the payment is on time if made on the next day that is not one of those | structural | IRS Publication 505 (2026), Tax Withholding and Estimated Tax, 'Saturday, Sunday, holiday rule' 'A legal holiday includes any legal holiday in the District of Columbia' (Instructions for Form 2210 (2025), Reminders). DC's Emancipation Day, April 16, is the one that most often moves the April instalment. | ✓ verified |
Annualised instalment method (Schedule AI / Pub. 505 Worksheet 2-9) 7
The period ends, annualisation multipliers, applicable percentages and prorated wage-base limits used when income arrives unevenly across the year.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
ai_annualisation_multipliers |
4, 2.4, 1.5, 1 | structural | IRS Publication 505 (2026), Tax Withholding and Estimated Tax, Worksheet 2-9 lines 2 and 5 identical to Form 2210 (2025) Schedule AI lines 2 and 5 | ✓ verified |
ai_applicable_percentages |
22.5%, 45%, 67.5%, 90% | structural | IRS Publication 505 (2026), Tax Withholding and Estimated Tax, Worksheet 2-9 line 22 identical to Form 2210 (2025) Schedule AI line 20 | ✓ verified |
ai_half_se_divisor |
8, 4.8, 3, 2 | structural | IRS Publication 505 (2026), Tax Withholding and Estimated Tax, Worksheet 2-9 lines 42-43 This is the line that tells you HOW the deductible half of SE tax enters period AGI: divide the ANNUALISED SE tax (line 41) by 8/4.8/3/2 and subtract the result when figuring line 1. Form 2210's Schedule AI does not spell this out; only Pub. 505 does. | ✓ verified |
ai_period_end_dates |
3/31/26, 5/31/26, 8/31/26, 12/31/26 | structural | IRS Publication 505 (2026), Tax Withholding and Estimated Tax, Worksheet 2-9 column headings same as Form 2210 (2025) Schedule AI with the year advanced. NO 2026 revision of Form 2210 exists; the 2026 figures were taken from Pub. 505 (2026). | ✓ verified |
ai_prorated_ss_limits_2026 |
46125, 76875, 123000, 184500 | indexed | IRS Publication 505 (2026), Tax Withholding and Estimated Tax, Worksheet 2-9 line 34 2026-specific. Form 2210 (2025) line 29 shows the 2025 equivalents 44025/73375/117400/176100. | ✓ verified |
ai_se_annualisation |
OASDI 0.496/0.2976/0.186/0.124; Medicare 0.116/0.0696/0.0435/0.029 | structural | IRS Publication 505 (2026), Tax Withholding and Estimated Tax, Worksheet 2-9 lines 37 and 39 identical to Form 2210 (2025) Schedule AI lines 32 and 34 | ✓ verified |
form_2210_revision_used |
2025 revision (there is no 2026 revision) | structural | Form 2210, rev. 2025 — the latest revision published; NO 2026 revision exists / Instructions for Form 2210 (2025), rev. Feb 17 2026 Checked https://www.irs.gov/forms-pubs/about-form-2210 on 2026-08-24: current revision is 2025; the only 2026-dated item is a 5-MAR-2026 update to the 2025 instructions. So the STRUCTURE here is the 2025 form's; the 2026 DOLLAR VALUES are from Pub. 505 (2026) Worksheet 2-9, which is a 2026 document. | ✓ verified |
Standard mileage rate 2
2026 has two business rates: one before 1 July and a higher one from 1 July. A single-rate table understates the second half of the year.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
MILEAGE_RATE_BUSINESS_H1 |
0.725 | annual-notice | IRS Notice 2026-10, 2026-4 I.R.B. 378 (29 Dec 2025) — 2026 business standard mileage rate; applies to miles driven BEFORE 1 July 2026 Quoted from the source: “For 2026, the standard mileage rate is 72.5 cents per mile” | ✓ verified |
MILEAGE_RATE_BUSINESS_H2 |
0.76 | annual-notice | IRS Announcement 2026-11, 2026-29 I.R.B. 49 (13 Jul 2026), modifying Notice 2026-10 — business rate for miles driven ON OR AFTER 1 Jul 2026 Quoted from the source: “(1) Business 76 cents per mile ... The standard mileage rates set forth in Notice 2026-10 continue to apply to deductible transportation expenses paid or incurred for business, medical, or moving expense purposes before July 1, 2026” | ✓ verified |
Form 1099-K reporting thresholds 2
The thresholds a third-party settlement organisation must exceed before it files, reverted by OBBBA to $20,000 and 200 transactions.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
FED_1099K_GROSS_THRESHOLD |
20000 | statutory | IRS IR-2025-107 (23 Oct 2025) — 1099-K threshold FAQs under OBBBA Quoted from the source: “third party settlement organizations are not required to file Forms 1099-K unless the gross amount of reportable payment transactions to a payee exceeds $20,000 and the number of transactions exceeds 200” | ✓ verified |
FED_1099K_TXN_THRESHOLD |
200 | statutory | IRS IR-2025-107 (23 Oct 2025), same sentence — 'exceeds 200' Quoted from the source: “and the number of transactions exceeds 200” | ✓ verified |
Home office, simplified method 2
The prescribed rate per square foot and the square-footage cap.
| constant | value | basis | source_document | verified_on |
|---|---|---|---|---|
HOME_OFFICE_MAX_SQFT |
300 | prescribed | Rev. Proc. 2013-13, via IRS Tax Topic 509 Quoted from the source: “up to a maximum of 300 square feet” | ✓ verified |
HOME_OFFICE_RATE |
5 | prescribed | Rev. Proc. 2013-13, via IRS Tax Topic 509 (Business use of home) Quoted from the source: “prescribed rate of $5 per square foot of the portion of the home used for business (up to a maximum of 300 square feet)” | ✓ verified |
What the basis column means
It answers one question — when does this number have to be read again? That is the difference between a table that ages gracefully and one that is quietly wrong next January.
- indexed
- Inflation-adjusted every year. Must be re-read from the new revenue procedure (or the SSA base page) before any later tax year is modelled.
- statutory
- Fixed in the Internal Revenue Code with no inflation adjustment. Changes only if Congress acts.
- structural
- A rate, ratio, date rule or form mechanic. Changes only if the IRS redesigns the form.
- indexed-from-2027
- Fixed for tax year 2026 but scheduled to start indexing for years beginning after 2026. The value most likely to be silently wrong in a model carried forward.
- annual-notice
- Set by the IRS for the year in a notice, and capable of being changed mid-year by a later announcement — as the 2026 business mileage rate was.
- prescribed
- A rate prescribed by a revenue procedure and left unchanged since. Not indexed; re-check only if that procedure is superseded.
The full rate schedules
A few rows of the table stand for whole schedules. Those are printed in full here, and carried in full in the JSON file.
2026 tax rate schedules (ordinary_brackets_2026)
Single
| Taxable income over | Base tax | Rate on the excess |
|---|---|---|
| $0 | $0 | 10% |
| $12,400 | $1,240 | 12% |
| $50,400 | $5,800 | 22% |
| $105,700 | $17,966 | 24% |
| $201,775 | $41,024 | 32% |
| $256,225 | $58,448 | 35% |
| $640,600 | $192,979.25 | 37% |
Married filing jointly
| Taxable income over | Base tax | Rate on the excess |
|---|---|---|
| $0 | $0 | 10% |
| $24,800 | $2,480 | 12% |
| $100,800 | $11,600 | 22% |
| $211,400 | $35,932 | 24% |
| $403,550 | $82,048 | 32% |
| $512,450 | $116,896 | 35% |
| $768,700 | $206,583.50 | 37% |
Married filing separately
| Taxable income over | Base tax | Rate on the excess |
|---|---|---|
| $0 | $0 | 10% |
| $12,400 | $1,240 | 12% |
| $50,400 | $5,800 | 22% |
| $105,700 | $17,966 | 24% |
| $201,775 | $41,024 | 32% |
| $256,225 | $58,448 | 35% |
| $384,350 | $103,291.75 | 37% |
Head of household
| Taxable income over | Base tax | Rate on the excess |
|---|---|---|
| $0 | $0 | 10% |
| $17,700 | $1,770 | 12% |
| $67,450 | $7,740 | 22% |
| $105,700 | $16,155 | 24% |
| $201,750 | $39,207 | 32% |
| $256,200 | $56,631 | 35% |
| $640,600 | $191,171 | 37% |
Qualifying surviving spouse uses the married-filing-jointly schedule (26 U.S.C. 1(j)(2)(A)).
Standard deduction and Additional Medicare Tax thresholds
Standard deduction (standard_deduction_2026)
| Single | $16,100 |
|---|---|
| Married filing jointly | $32,200 |
| Married filing separately | $16,100 |
| Head of household | $24,150 |
| Qualifying surviving spouse | $32,200 |
Additional Medicare Tax at 0.9% above (additional_medicare_thresholds)
| Single | $200,000 |
|---|---|
| Married filing jointly | $250,000 |
| Married filing separately | $125,000 |
| Head of household | $200,000 |
| Qualifying surviving spouse | $200,000 |
Section 199A thresholds and phase-in ranges
| Filing status | Threshold | Top of phase-in | Phase-in width |
|---|---|---|---|
| Single | $201,750 | $276,750 | $75,000 |
| Married filing jointly | $403,500 | $553,500 | $150,000 |
| Married filing separately | $201,775 | $276,775 | $75,000 |
| Head of household | $201,750 | $276,750 | $75,000 |
| Qualifying surviving spouse | $201,750 | $276,750 | $75,000 |
Deduction rate 20%. Minimum deduction $400 where aggregate qualified business income from active trades or businesses is at least $1,000 (26 U.S.C. 199A(i), added by OBBBA sec. 70105(b); not indexed until 2027).
Self-employment tax and the estimated-tax tests
Schedule SE
| Net earnings factor | 92.35% |
|---|---|
| Filing floor | $400 |
| Social security (OASDI) rate | 12.4% |
| Medicare rate | 2.9% |
| Deductible share | 50% |
| Social security wage base | $184,500 |
Form 1040-ES safe harbour
| Of this year's tax | 90% |
|---|---|
| Of last year's tax | 100% |
| Of last year's tax, higher incomes | 110% |
| Prior-year AGI that triggers it | $150,000 |
| …filing separately | $75,000 |
| De minimis: no payments below | $1,000 |
2026 payment due dates: · · · . Business standard mileage rate $0.725 per mile before 2026-07-01, $0.76 per mile from 2026-07-01.
Annualised instalment method (Pub. 505 Worksheet 2-9)
| Period ends | 2026-03-31 | 2026-05-31 | 2026-08-31 | 2026-12-31 |
|---|---|---|---|---|
| Annualisation multiplier | ×4 | ×2.4 | ×1.5 | ×1 |
| Applicable percentage | 22.5% | 45% | 67.5% | 90% |
| Prorated social security limit | $46,125 | $76,875 | $123,000 | $184,500 |
| Annualised OASDI rate | 49.6% | 29.76% | 18.6% | 12.4% |
| Annualised Medicare rate | 11.6% | 6.96% | 4.35% | 2.9% |
| Half-of-SE-tax divisor | ÷8 | ÷4.8 | ÷3 | ÷2 |
What we built on it
Quarterly Estimated Tax Calculator
The free calculator that uses these constants directly — what you owe for 2026, split across the four payment dates.
US Self-Employed Tax Engine — 1099 & Quarterly Estimated Taxes · Tax Year 2026
The paid workbook this table was assembled for: annualised instalments, a payment calendar, and every figure traceable to the row that produced it.
This is a reference table, not tax advice. Verify any figure against the linked primary document before relying on it.
