--- url: https://thresholds.pages.dev/calendar/ title: "US Money Calendar: Every Deadline That Matters" updated: 2026-09-07 site: Thresholds sources: - https://www.irs.gov/pub/irs-pdf/f1040es.pdf - https://www.treasurydirect.gov/savings-bonds/i-bonds/i-bonds-interest-rates/ - https://www.healthcare.gov/quick-guide/dates-and-deadlines/ - https://www.irs.gov/publications/p969 - https://www.ssa.gov/oact/cola/colasummary.html --- # US Money Calendar: Every Deadline That Matters Every US money deadline that carries a penalty, with the exact date and the days remaining. Weekday- and holiday-adjusted. Updated 2026-09-07. 33 dated events from 2026 through 2027: estimated-tax installments, HSA and FSA cut-offs, Marketplace enrollment, I bond rate announcements and the dates next year's limits are set. Every deadline that falls on a weekend or a legal holiday is already shifted — the fourth 2027 estimated-tax installment is 2028-01-18 because January 15 is a Saturday and the Monday is Martin Luther King Jr. Day. Figures verified 2026-09-07. Certainty is stated, never hidden. "fixed" is a statutory or published date; "scheduled" is a recurring date that is known; "expected" is a historically reliable window whose date has not been published, and gets no invented date; "plan-specific" depends on your own employer's plan document. ## Every event - 2026-04-15 — Estimated tax — first installment for 2026 [tax; fixed; applies if you pay estimated tax] - 2026-06-15 — Estimated tax — second installment for 2026 [tax; fixed; applies if you pay estimated tax] - 2026-09-15 — Estimated tax — third installment for 2026 [tax; fixed; applies if you pay estimated tax] - no date published yet (October–November 2026; window 2026-10-01 to 2026-11-30) — IRS annual inflation adjustments, including the 2027 health FSA limits — expected [fsa; expected] - no date published yet (mid-October 2026; window 2026-10-01 to 2026-10-31) — SSA cost-of-living adjustment and the 2027 earnings-test limits — expected [ss; expected] - 2026-11-01 — Marketplace open enrollment opens for 2027 coverage [health; fixed] - 2026-11-01 — New I bond rates take effect (November 2026 – April 2027) [ibonds; scheduled] - 2026-12-01 — HSA last-month rule test date for 2026 [hsa; fixed; applies if you were not HDHP-covered all year] - 2026-12-15 — Last day to enroll for Marketplace coverage starting January 1, 2027 [health; fixed] - 2026-12-31 — Health FSA plan year ends — spend-by date for most calendar-year plans [fsa; plan-specific; applies if your plan year is the calendar year] - no date published yet (January 2027; window 2027-01-01 to 2027-01-31) — HHS poverty guidelines for 2027 — expected [health; expected] - 2027-01-15 — Marketplace open enrollment closes for 2027 coverage [health; fixed] - 2027-01-15 — Estimated tax — fourth installment for 2026 [tax; fixed; applies if you pay estimated tax] - 2027-02-01 — File your 2026 return and pay in full — and the January 15 installment is not required [tax; fixed; applies if you skipped the fourth installment] - 2027-03-15 — Latest a grace period can run for a December 31, 2026 plan year [fsa; plan-specific; applies if your plan offers a grace period] - 2027-03-31 — A common health FSA claim-submission (run-out) deadline — not a rule [fsa; plan-specific; applies if your plan sets a 90-day run-out] - 2027-04-15 — Estimated tax — first installment for 2027 [tax; scheduled; applies if you pay estimated tax] - 2027-04-15 — Federal income tax return for 2026 due (or file for an extension) [tax; fixed] - 2027-04-15 — Last day to make 2026 HSA contributions [hsa; fixed] - no date published yet (May 2027; window 2027-05-01 to 2027-05-31) — IRS revenue procedure with the 2028 HSA and HDHP limits — expected [hsa; expected] - 2027-05-01 — New I bond rates take effect (May – October 2027) [ibonds; scheduled] - 2027-06-15 — Estimated tax — second installment for 2027 [tax; scheduled; applies if you pay estimated tax] - no date published yet (July–August 2027; window 2027-07-01 to 2027-08-31) — IRS revenue procedure with the 2028 applicable percentages — expected [health; expected] - 2027-09-15 — Estimated tax — third installment for 2027 [tax; scheduled; applies if you pay estimated tax] - no date published yet (October–November 2027; window 2027-10-01 to 2027-11-30) — IRS annual inflation adjustments, including the 2028 health FSA limits — expected [fsa; expected] - no date published yet (mid-October 2027; window 2027-10-01 to 2027-10-31) — SSA cost-of-living adjustment and the 2028 earnings-test limits — expected [ss; expected] - 2027-10-15 — Extended federal income tax return for 2026 due [tax; fixed; applies if you filed an extension] - no date published yet (November 1, 2027; window 2027-11-01 to 2027-11-01) — Marketplace open enrollment opens for 2028 coverage — expected [health; expected] - 2027-11-01 — New I bond rates take effect (November 2027 – April 2028) [ibonds; scheduled] - 2027-12-01 — HSA last-month rule test date for 2027 [hsa; fixed; applies if you were not HDHP-covered all year] - 2027-12-31 — Health FSA plan year ends — spend-by date for most calendar-year plans [fsa; plan-specific; applies if your plan year is the calendar year] - 2027-12-31 — Testing period ends for a 2026 last-month-rule contribution [hsa; fixed; applies if you used the last-month rule for 2026] - 2028-01-18 — Estimated tax — fourth installment for 2027 [tax; scheduled; applies if you pay estimated tax] ## Downloadable calendars 21 of the 33 events have a real published date and are not set by your own plan, so they can go in a calendar file: https://thresholds.pages.dev/calendar/thresholds-2026-27.ics, plus one file per section for estimated taxes, HSA, health insurance and I bonds. There is no Social Security or FSA file, because every event in those two sections is either an unpublished announcement window or a date your own plan sets. Each entry is all-day with a reminder seven days before at 09:00 local time. ## Sources - [2026 Form 1040-ES; IRS "When to pay estimated tax"](https://www.irs.gov/pub/irs-pdf/f1040es.pdf) - [TreasuryDirect — I bonds interest rates](https://www.treasurydirect.gov/savings-bonds/i-bonds/i-bonds-interest-rates/) - [HealthCare.gov — dates and deadlines](https://www.healthcare.gov/quick-guide/dates-and-deadlines/) - [IRS Publication 969](https://www.irs.gov/publications/p969) - [SSA — cost-of-living adjustment summary](https://www.ssa.gov/oact/cola/colasummary.html) --- Information, not advice. Figures verified 2026-09-07. https://thresholds.pages.dev/calendar/