How the calculators work
Every calculator on this site runs in your browser on one engine and one parameter file. The parameter file holds each exemption, table and class of heir with the official text it comes from and the date it was read (October 19, 2026 for this edition, deaths from January 1, 2026 to December 31, 2026). This page lists the rules, the formulas, the tests and what is left out.
1. The estate you enter
The amount is the net estate: everything included in the federal gross estate (real estate, accounts, securities, retirement accounts, life insurance the deceased owned, a business interest), minus debts, funeral costs and administration expenses. The share left to a spouse is deducted as the marital deduction, which assumes the spouse is a US citizen; the share left to charity is deducted too. What remains is split equally between the heirs you describe.
2. State estate taxes
Each state computes its tax in its own way, and the engine follows the method each state prints, not a single rate. Several states still use the table of the old federal credit for state death taxes, called Table B, applied to the "adjusted taxable estate", which is the estate minus $60,000.
| State | Method | Property elsewhere | Lifetime gifts | Read on |
|---|---|---|---|---|
| Connecticut | Table applied to the amount above the exemption | tax times in-state share | all taxable gifts since 2005 | Connecticut DRS, Estate and gift tax information; Connecticut General Statutes, chapter 217, sections 12-391 and 12-392 |
| District of Columbia | Brackets printed in estate amounts, the first one starting at the threshold with no tax | tax times in-state share | not added | DC Office of Tax and Revenue, 2026 D-76 instructions; DC Office of Tax and Revenue, estate tax information |
| Hawaii | Table applied to the amount above the exemption | tax times in-state share | reduce the exclusion | Hawaii Department of Taxation, Form M-6 instructions (Rev. 2025) |
| Illinois | Attorney General interrelated computation on Table B | tax times in-state share | in the threshold test | Illinois Attorney General, Estate taxes; Illinois Attorney General, estate tax fact sheet |
| Maine | Table applied to the amount above the exemption | tax times in-state share | within 1 year | Maine Revenue Services, Estate tax (706ME); Maine Revised Statutes, Title 36, section 4103 |
| Maryland | Lesser of 16 % above the exclusion and the apportioned Table B credit | tax times in-state share | in the credit computation | Comptroller of Maryland, Form MET 1 (Rev. 07/26); Maryland Tax-General Article 7-309, estate tax exclusion and portability |
| Massachusetts | Table B on (estate minus $60,000), minus $99,600 | property located there only | not added | Massachusetts DOR, Estate tax guide |
| Minnesota | Table applied to the amount above the exemption | tax times in-state share | within 3 years | Minnesota Statutes 291.03, rates; Minnesota Statutes 291.016, Minnesota taxable estate |
| New York | Section 952 table, credit phased out up to 105 % of the exclusion | property located there only | within 3 years | New York Department of Taxation and Finance, Estate tax; New York Tax Law 952, tax and applicable credit |
| Oregon | Brackets printed in estate amounts, the first one starting at the threshold with no tax | tax times in-state share | not added | Oregon DOR, 2026 Form OR-706 instructions; Oregon DOR, 2026 summary of legislation |
| Rhode Island | Table B on (estate minus $60,000), minus a fixed credit of $87,940 | tax times in-state share | not added | Rhode Island Division of Taxation, Estate tax; Rhode Island Form RI-706 (rate schedule and 2026 credit) |
| Vermont | Table applied to the amount above the exemption | tax times in-state share | within 2 years | Vermont Department of Taxes, Estate tax; 32 V.S.A. 7442a, Vermont estate tax rate |
| Washington | Table applied to the amount above the exemption | tax times in-state share | not added | Washington DOR, Estate tax tables; Washington DOR, Estate tax |
Washington has two tables in 2026: deaths from January 1 to June 30 use an exclusion of $3,076,000 and the rates in force since July 1, 2025; deaths from July 1 use $3,000,000 and the table of ESB 6347. The calculator asks for the half of the year. Maryland's tax is reduced by the Maryland inheritance tax paid, as line 14a of Form MET 1 provides. Hawaii and Maryland let the survivor use a late spouse's unused state exclusion; the engine applies it, capped at the state exclusion, when you enter a DSUE amount.
3. Real estate in another state
For a resident, real estate in another state is taken out of the tax base of the home state. In the states that apportion, the tax on the whole estate is multiplied by the share of the estate located in the state; New York and Massachusetts instead compute the tax on the property they tax alone (Tax Law section 960, Massachusetts estate tax guide). The state where the property sits computes its own nonresident tax the same way. Tangible property such as furniture or a car is treated like the rest of the estate.
4. Inheritance taxes
Each heir's share is placed in the class the state's law gives to that relationship, and the class rate or brackets apply to the share, before the estate pays its own taxes. Pennsylvania applies flat rates, New Jersey and Kentucky brackets after a class exemption, Nebraska a flat rate above a class exemption, Maryland 10 % with a list of exempt relatives. A nonresident's real estate is taxed by the state where it lies: New Jersey by the ratio of that property to the whole estate, Kentucky with a prorated exemption, the others directly on the property. Iowa's tax ended for deaths from January 1, 2025 and is not computed.
5. Federal estate tax
The federal tax is the tentative tax of 26 U.S.C. 2001(c) on the taxable estate plus lifetime taxable gifts, minus the tentative tax on the applicable exclusion: $15,000,000 for 2026 (Rev. Proc. 2025-32), plus any unused exclusion of a late spouse elected on Form 706. State death taxes, estate and inheritance, are deducted from the federal taxable estate (section 2058). Gift tax already paid is not modelled; the engine assumes lifetime gifts stayed within the exclusion.
6. Tests
Every published table is checked row by row: the base amount printed for each bracket must equal the tax of the previous rows at their rates, so a typing error in a table stops the build. The official examples are reproduced:
| Case | Engine | Official figure |
|---|---|---|
| Illinois, $5,000,000 taxable estate | $285,714 | Attorney General: $285,714 |
| Illinois, $3,000,100 and $1,000,000 of gifts | $29 | Attorney General: $28 (cents dropped) |
| District of Columbia, $5,000,000 | $1,299 | D-76 table: $1,299 |
| Federal tentative tax on $15,000,000 | $5,945,800 | Form 706 instructions: $5,945,800 |
| Rhode Island credit against Table B at the threshold | $87,940 | RI-706: $87,940 |
| Massachusetts, Table B on $1,940,000 | $99,600 | DOR credit: $99,600 |
7. What is not modelled
- Valuation: appraisals, discounts, special-use valuation of farms and closely held business deductions.
- Qualified terminable interest property elections made at a first death, and state QTIP elections.
- Credits for tax paid to another state on the same property, beyond Maryland's credit for its own inheritance tax.
- The generation-skipping transfer tax, gift tax already paid and the credit for tax on prior transfers.
- Interest, penalties and payment plans.
Corrections: contact page. These are estimates made to compare situations, not a return and not legal or tax advice.