Connecticut Estate tax
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Connecticut Estate Tax Calculator

Connecticut Estate Tax Calculator (2025) — CT-706 Estimate

Last updated: 9 Nov 2025

Connecticut Estate Tax — Calculator

Estimate Connecticut estate tax with year-based exemptions, CT taxable gifts addback, and (for nonresidents) CT-situs apportionment. Clear step-by-step breakdown with printable results.

Get help: Connecticut Estate Tax (fixed-fee)
Heads-up. The CT exemption matches the federal basic exclusion for the year of death; amounts above the exemption are taxed at a flat 12%. For nonresidents, the estimate is limited to the Connecticut portion via apportionment. Always reconcile with official CT-706/709 instructions.

Calculator

Exemption follows CT guidance for each year.
Total gross estate per federal rules, before deductions.
Admin expenses, debts, mortgages, marital/charitable, etc. (federal concepts).
Aggregate Connecticut taxable gifts made on/after 1/1/2005 (reduces remaining exemption).
Exemption: $13,990,000 CT rate: 12% Due: 6 months

Results

Federal gross estate—
Less: deductions—
Net estate (federal concept)—
+ CT taxable gifts since 1/1/2005—
CT taxable estate (pre-apportion)—
CT taxable amount over exemption—
CT tentative tax @ 12%—
Less: extension/estimated payments—
Balance due / (refund)—

How to use this calculator

Step-by-step

  1. Select the year of death. The CT exemption loads automatically (e.g., $13.61M for 2024; $13.99M for 2025).
  2. Choose residency. Nonresidents are taxed only on Connecticut-situs real/tangible property; enter the CT-situs net when prompted.
  3. Enter the federal gross estate and deductions (federal concepts) → net estate = gross minus deductions.
  4. Add CT taxable gifts since 1/1/2005 (unified estate & gift system).
  5. Review CT taxable estate, excess over exemption, and the 12% tax.
  6. Subtract extension/estimated payments to view balance due.

Notes & tips

  • Due date: 6 months after death. Filing can be extended; payment is still due at 6 months unless a payment extension is granted.
  • Apportionment (nonresident): Calculator applies CT share ≈ CT-situs net ÷ total net estate; follow CT-706/709 instructions for deduction assignment.
  • QTIP/portability: CT generally follows federal marital deduction/QTIP; no state-only portability.
  • Valuation: Use qualified appraisals for CT real/tangible property; keep workpapers for DRS/Probate.
Disclaimer. This tool is an estimate and can’t cover special rules (farm/special-use valuation, §6166 installments, unique credits/deductions, QTIP variations). Reconcile with the current CT-706/709 forms and instructions.
Related pages: Overview · Forms & Deadlines · Nonresident Guide · Planning · Cases · Service Packages

References

  1. CGS § 12-391 — Framework, resident vs. nonresident, CT-situs property, domicile.
  2. DRS — CT-706 Series (forms, line instructions, extensions) and CT-706 NT instructions.
  3. CT Legislative/DRS guidance — flat 12% CT rate; exemption mirrors federal amount.