Transparency
Data updates
This site runs on figures published by the IRS, the Social Security Administration and state
revenue departments. Those figures change once a year, and occasionally get corrected. This page
records every change we make, when we made it, and which tax year is currently live.
Tax year status
Only a year marked Live drives the calculators. A year marked
Tracking has been announced by the source agency but is not complete, so it is
recorded in our data file and kept out of the tools until every schedule is published.
What changed
November 8, 2026 · Data
2027 bracket tables completed from Revenue Procedure 2026-35
The IRS news release of 5 November 2026 lists only the single and joint thresholds, so the head-of-household and married-filing-separately schedules for 2027 were carried as open items. Revenue Procedure 2026-35, published alongside that release, contains the full Table 1-4 schedules and they are now entered. Nothing in the 2027 tables was guessed: every threshold below is read from the revenue procedure. The calculators still run on 2026 figures, which were re-checked against IR-2025-103 and the Social Security Administration and are unchanged.
- 2027 head of household: 10% to $18,250, 12% to $69,650, 22% to $109,100, 24% to $208,300, 32% to $264,550, 35% to $661,350, 37% above
- 2027 married filing separately: 10% to $12,800, 12% to $52,025, 22% to $109,125, 24% to $208,325, 32% to $264,550, 35% to $396,825, 37% above
- Still open for 2027: California and New York schedules, plus the CA SDI rate and NY SDI/PFL caps
- Citation fix: the tax year 2026 inflation-adjustment source now points at IR-2025-103, after the previous IRS URL began returning 404
November 8, 2026 · Data
Tax year 2027 figures are now being tracked
The IRS published the 2027 inflation adjustments on 5 November 2026, and the Social Security Administration set the 2027 wage base at $192,300 on 14 October. Both are entered in our data file and flagged as unverified where the source has not yet published a schedule. The calculators still run on 2026 figures until every 2027 item is confirmed.
- 2027 standard deduction: $16,600 single, $33,200 joint, $24,925 head of household
- 2027 Social Security wage base: $192,300, up from $184,500
- Still pending: head-of-household and married-filing-separately bracket tables (Revenue Procedure 2026-35), California and New York 2027 schedules
November 8, 2026 · Data
Every figure now comes from one file
Tax parameters previously lived in four places: the browser bundle, two Python build scripts and a hand-written guide table. They now live in data/tax-params.json and are compiled into the site. A figure can no longer disagree with itself.
- data/tax-params.json is the only place a rate, threshold or deduction may be edited
- Regression checks pin four known-good results (California $100,000, New York $75,000 and $100,000, Texas $75,000) and fail the build if any of them move
- A drift detector scans the hand-written pages for dollar amounts that belong to a previous tax year
November 8, 2026 · Site
State paycheck calculators published
Three states now calculate from their statutory schedules instead of an approximate effective rate: California (nine brackets plus SDI), New York (nine brackets plus SDI and paid family leave) and Texas, which has no wage tax at all.
- California and New York apply their own standard deductions and bracket tables
- SDI and PFL are charged on gross wages, not the 401(k)-reduced base, which matches how those premiums are actually withheld
- The other 48 jurisdictions keep an editable effective rate, labelled as an approximation
How a new tax year gets published here
The IRS announces inflation adjustments in the autumn, the Social Security Administration sets the
wage base in October, and most states publish their schedules between December and February. A new
year is added to our data file as soon as it is announced, with every unconfirmed item listed as
open. The calculators switch over only when the last schedule arrives, and this page records the
switch.
Spotted a figure that looks wrong? Tell us and it gets checked against
the primary source before anything else happens.