Equalizer planning is an estate planning strategy that deliberately pays some estate tax at the first spouse’s death instead of deferring all tax to the second death. The goal is to equalize the marginal tax brackets across both estates, minimizing the combined estate tax the family pays across both deaths.
For most married couples, the standard approach works best: claim the optimum marital deduction to eliminate estate tax at the first death and pay tax only when the surviving spouse dies. But for estates large enough that the standard approach produces a significantly larger taxable estate at the second death, equalizer planning can reduce total taxes by spreading the tax burden more evenly.
When the Equalizer Approach Applies
The equalizer approach is relevant only for very large estates. Under current federal law, the estate tax rate is a flat 40% on amounts above the applicable exclusion ($15 million in 2026). Because the federal rate is flat, not graduated, there is no bracket arbitrage at the federal level; equalizing the two estates does not move dollars from a higher bracket to a lower one.
This differs from earlier periods when the federal estate tax used graduated rates reaching 48% or higher. Under those rate structures, equalizer planning produced substantial savings by ensuring neither estate was taxed at a higher marginal rate than necessary.
Even under the current flat federal rate, equalizer planning may produce savings in two scenarios. First, when state estate taxes apply with graduated rate structures and lower exemption thresholds, equalizing the two estates reduces total state estate tax. Second, when both spouses are likely to die within a relatively short period, paying tax at the first death avoids IRC § 2044 inclusion of marital trust assets in the surviving spouse’s estate. In quick-succession scenarios, deferral is less valuable.
The Six-Month Equalizer Plan
A sophisticated variation combines the equalizer approach with a survivorship condition. The estate plan uses a conditional formula:
If the surviving spouse survives the decedent by six months, the plan uses the standard optimum marital deduction, producing zero tax at the first death. If the surviving spouse does not survive by six months, the plan uses an equalizer formula that pays some tax at the first death to reduce combined taxes.
This conditional approach works because the six-month survivorship condition is permitted under IRC § 2056(b)(3) without disqualifying the marital deduction (as long as the surviving spouse actually survives the period). The equalizer applies only in the scenario where both estates will be settled nearly simultaneously, which is precisely when equalization produces the greatest benefit.
The six-month equalizer plan gives the family the best of both approaches: full deferral when the surviving spouse has a long remaining life expectancy (where deferral is most valuable), and equalization when both spouses die in close succession (where deferral provides little benefit).
For more on how survivorship conditions interact with marital deduction qualification, see our discussion of survivorship requirements and the six-month rule in estate planning.
The Time-Value of Money Objection Is Wrong
The most common objection to equalizer planning is the “time-value of money” argument: paying estate tax at the first death wastes dollars that could have been invested during the surviving spouse’s remaining life. This argument sounds intuitive but is mathematically incorrect.
The argument assumes retaining the tax dollars in the marital trust produces greater after-tax wealth for beneficiaries because those dollars can grow during the surviving spouse’s life. But this analysis ignores a critical fact: the retained dollars and their growth will be taxed at 40% in the surviving spouse’s estate at the second death.
The mathematics work out as follows. If $X is paid in tax at the first death, the estate loses $X immediately. If $X is instead retained in the marital trust, it grows to $X(1+r)^n by the second death (where r is the annual return and n is the number of years). At the second death, 40% of the entire amount (both the original $X and its growth) is taxed. The after-tax result of the equalizer approach equals or exceeds the deferral approach, regardless of the investment return or the surviving spouse’s life expectancy.
This result is counterintuitive, which is why the time-value objection persists among practitioners who have not worked through the algebra. The conclusion is definitive: for estates in the top bracket, the equalizer approach never produces a worse result than full deferral, and it frequently produces a better one.
The IRC § 2013 Previously Taxed Property Credit
When both spouses die within ten years of each other, the surviving spouse’s estate may be entitled to a credit under IRC § 2013 for estate tax paid at the first death on property that is also taxed at the second death. The credit starts at 100% if the surviving spouse dies within two years and is reduced by 20% for each additional two-year period, disappearing entirely after ten years.
The IRC § 2013 credit provides additional support for the equalizer approach in quick-succession scenarios. If the surviving spouse dies shortly after the first spouse, the credit offsets much of the double taxation, and the equalization of the two estates reduces the total tax base. The six-month equalizer plan is designed to capture exactly this interaction: it applies the equalizer when quick succession is most likely (within six months) and reverts to full deferral otherwise.
Practical Considerations
Equalizer planning adds complexity to estate administration. The personal representative must calculate not just the optimum marital deduction (producing zero tax) but the equalizer amount (producing the minimum combined tax across both estates). This calculation requires assumptions about the surviving spouse’s estate at the second death, introducing uncertainty about future asset values, the surviving spouse’s spending, and changes in tax law.
For most families, the standard optimum marital deduction approach is appropriate. Equalizer planning is a specialized strategy for very large estates, estates subject to state death taxes with graduated rates, and situations where both spouses have serious health concerns making quick succession likely.
For an overview of the standard approach and how the formula is calculated, see our guide to the optimum marital deduction and how planners calculate it.