Washington State Estate Tax Calculator (2026 Version)

The Washington State Estate Tax Calculator provided below estimates state estate taxes for decedents dying on or after July 1, 2026. Note that the calculator’s formulas apply the new estate tax law, Senate Bill 6347, enacted in early 2026 but effective as of July 1, 2026.

Note: Instructions and additional information appear below the calculator input and outputs.

Instructions for Washington State Estate Tax Calculator

You need to describe an estate using the roughly half a dozen inputs. But you will also find it useful to understand four things as you start:

First, Washington state subtracts the following items from your taxable estate: Liabilities, spousal transfers, estate administration costs, charitable contributions and then the “standard” exclusion equal to $3,000,000. Note this $3,000,000 exclusion stays fixed. The legislature contemplated adjusting it for inflation–and the original bill included an inflation adjustment–but the inflation adjustment was removed. (In effect, then, inflation shrinks the size of the exclusion over time.)

Second thing to know: A special qualified family owned business interest deduction also exists and that can amount to another $3,076,000. But that deduction is very difficult to use and rather problematic. That exclusion stays fixed too and thus inflation also shrinks its size over time.

A third point: If the decedent directly owned out-of-state real estate, the formulas adjust for this. Washington state doesn’t tax its residents on real property held out of state. (Those other states, by the way, might.) But as an example, if someone holds real estate outside Washington state that amounts to 25 percent of the person’s estate? Washington state only taxes the remaining 75 percent. Note however that under current rules, if a Washington decedent owns an LLC that owns out of state property? That isn’t considered out of state property. Rather, the LLC is considered an intangible asset inside Washington state.

Fourth, once a decedent’s state crosses the $3,000,000 threshold, the estate tax formula uses a sliding scale over a $9,000,000 “band” which starts at 10 percent and rises to 20 percent. Note that $9,000,000 “band” stays fixed too. Thus, it also shrinks in size over time due to inflation.

Note: If the inflation shrinkage thing seems off, remember that if inflation runs 5 percent some year? That $3,000,000 exclusion should be adjusted up by 5 percent to $3,150,000 to be just as big. Similarly, the $1,000,000 “10 percent” estate tax bracket which is the first estate tax bracket in the $9,000,000 band? Again, if inflation runs 5 percent some year, that bracket should be adjusted up by 5 percent to $1,050,000. As should all the other tax brackets as well. Federal tax laws by the way often do adjust for inflation.

Some Other Stuff to Know

Some other things helpful to know:

A wrinkle for people who hold real property inside or outside of Washington state: The values you enter for that property in the “Washington state assets” and “Non-Washington state assets” boxes need to be net of any nonrecourse debt like mortgages the decedent isn’t personally liable for. Use the liabilities box to show only the total recourse liabilities.

Please consider the calculation results an estimate. They should however give you a good sense of the taxes an estate pays.

The Washington Department of Revenue provides useful resources at its website and this is where you probably want to start any reading there: Washington Estate Tax.

Other Resources

For decedents dying between July 1, 205 and June 30,2026, use this calculator: Washington State Estate Tax Calculator (2025 Version).

For decedents dying before July 1, 2025, use this calculator: Washington State Estate Tax Calculator.