To calculate trust and estate income tax for 2026, start with the entity’s gross income, subtract allowable deductions and any distribution deduction for amounts paid to beneficiaries, apply the compressed rate schedule that reaches 37% at just $16,000 of taxable income,1Internal Revenue Service. Rev. Proc. 2025-32 then add the 3.8% Net Investment Income Tax if the entity retained investment income above the threshold. The fiduciary — executor for an estate, trustee for a trust — is personally responsible for running the numbers and paying what’s owed. Because the brackets compress so quickly, every deduction and every distribution decision moves the tax bill in a real way.
Who Has to Run This Calculation
A domestic estate must file Form 1041 and calculate income tax if it has gross income of $600 or more during the tax year.2Internal Revenue Service. File an Estate Tax Income Tax Return A trust has to file if it has any taxable income, gross income of $600 or more, or a nonresident alien beneficiary.
One boundary matters before you do any math. If the trust is a grantor trust — the person who created it kept enough control, such as the power to revoke it or swap assets — the trust’s income is taxed on the grantor’s personal return, not calculated separately on Form 1041.3Office of the Law Revision Counsel. 26 U.S. Code 671 – Trust Income, Deductions, and Credits Attributable to Grantors and Others as Substantial Owners The trust itself owes no income tax. Everything below applies to non-grantor trusts and to estates, which pay tax as separate entities.
Step 1: Add Up Gross Income
Gross income for a trust or estate looks a lot like gross income for an individual: interest from bank accounts, dividends, capital gains, rent, royalties, and the entity’s share of any partnership or S corporation income reported on a Schedule K-1.
Two things trip fiduciaries up here.
First, keep principal separate from income. Principal is the property originally placed in the trust or inherited through the estate, and it isn’t taxable. The rent a trust-owned property throws off is income; the property itself is not. The trust document typically defines the line, and that definition drives the calculation.
Second, use the right basis for anything the estate sells. Most assets a decedent owned receive a new tax basis equal to fair market value on the date of death.4Office of the Law Revision Counsel. 26 USC 1014 – Basis of Property Acquired From a Decedent Stock the decedent bought for $10,000 that was worth $100,000 at death has a basis of $100,000 in the estate’s hands. Selling it for $100,000 produces no taxable gain. Calculate gain using the original purchase price and you’ll overstate income dramatically. The step-up does not apply to income the decedent had earned but not yet collected — unpaid wages, retirement distributions, accrued bond interest — which is taxed as income in respect of a decedent at ordinary rates with no basis adjustment.
Track tax-exempt interest separately. Municipal bond interest stays out of taxable income, but you’ll need the figure later when calculating distributable net income and when allocating expenses.
Step 2: Subtract Allowable Deductions
Several categories of expenses come off gross income before you apply the rates.
Fees paid to the executor, trustee, attorney, accountant, and tax preparer are deductible because they exist only because the fiduciary structure exists.5Internal Revenue Service. Instructions for Form 1041 Investment advisory fees tied to managing the entity’s portfolio and costs of maintaining trust-owned property also qualify. The working test: would this expense have been incurred if an individual held the property outright? If not, the entity can deduct it. That distinction matters because the individual-level miscellaneous itemized deduction remains suspended into 2026, but trust-specific administration expenses aren’t classified as miscellaneous itemized deductions and stay fully deductible for the entity.
Charitable contributions are deductible only if the trust document or will directs that income be paid to a qualified charity. Trusts and estates have no percentage-of-income cap on charitable deductions, but a trustee cannot decide unilaterally to donate income and claim the deduction. The authority has to be in the governing document.
State and local taxes paid by the entity are deductible up to $40,000 for 2026 for most taxpayers. Each non-grantor trust is treated as its own taxpayer, so each gets its own cap. The cap phases down for entities with modified adjusted gross income between $500,000 and $600,000 but never drops below $10,000.
Step 3: Apply the Distribution Deduction Using DNI
This is the pivot in the calculation. When a trust or estate distributes income to beneficiaries, the entity deducts the distribution and the beneficiary reports the income instead. Distributable net income (DNI) is the ceiling on how much can shift.
Start with taxable income after the deductions above, then add back tax-exempt interest (reduced by any expenses allocable to it). Capital gains are generally excluded from DNI and stay taxed at the entity level, unless the trust document or local law treats them as distributable income. The result is the maximum amount of income that can pass out to beneficiaries through the distribution deduction.
DNI also controls the character of what the beneficiary receives. If the trust earned $5,000 in dividends and $3,000 in interest, a distribution carries those proportions on the beneficiary’s Schedule K-1. Any amount distributed above DNI is treated as a tax-free return of principal.
Simple trusts — those required by their terms to distribute all income currently — get the distribution deduction automatically for the income they must pay out. Complex trusts have discretion, and that discretion is where planning happens: distributing investment income to a beneficiary in a lower bracket often produces a smaller combined tax bill than accumulating it inside the trust at 37%.
Step 4: Apply the 2026 Rates and the Exemption
Before applying the rates, subtract the entity’s personal exemption. Estates get $600. Simple trusts get $300. Complex trusts get $100.6Office of the Law Revision Counsel. 26 USC 642 – Special Rules for Credits and Deductions These amounts are fixed by statute and don’t adjust for inflation.
Then run the taxable income through the 2026 brackets:1Internal Revenue Service. Rev. Proc. 2025-32
- 10% on taxable income up to $3,300
- 24% on $3,301 to $11,700
- 35% on $11,701 to $16,000
- 37% on anything over $16,000
For context, a single individual doesn’t reach the 37% bracket until taxable income exceeds roughly $626,350. A trust hits the same rate at $16,001. The compression is deliberate: Congress designed it to discourage parking income inside trusts. In practice, it means the distribution decision in Step 3 is where most of the tax planning happens.
Step 5: Add the Net Investment Income Tax If It Applies
On top of the regular income tax, a trust or estate may owe a 3.8% Net Investment Income Tax. The NIIT applies to the lesser of the entity’s undistributed net investment income or the amount by which its adjusted gross income exceeds the threshold where the highest bracket begins.7Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax For 2026, that threshold is the same $16,000 where the 37% rate takes over.1Internal Revenue Service. Rev. Proc. 2025-32
Net investment income covers interest, dividends, capital gains, rental income, and royalties. It doesn’t include wages, self-employment income, or Social Security. Charitable trusts, grantor trusts, and certain exempt trusts are not subject to the NIIT.
The distribution planning from Step 3 reappears here. Investment income distributed to a beneficiary whose individual AGI is below the NIIT threshold ($200,000 single, $250,000 married filing jointly) escapes the 3.8% surtax entirely. Accumulate the same income inside the trust and you can stack the 37% rate with the 3.8% NIIT, pushing the effective federal rate above 40%.
Estimated Payments So You Don’t Owe a Penalty
A trust or estate that expects to owe $1,000 or more after withholding and credits generally has to make quarterly estimated payments on Form 1041-ES.8Internal Revenue Service. Estimated Income Tax for Estates and Trusts – 2026 Form 1041-ES To avoid an underpayment penalty, payments plus withholding need to cover the smaller of 90% of the current year’s tax or 100% of the prior year’s tax (110% if the prior year’s AGI exceeded $150,000).
Estates get a real break. A decedent’s estate is exempt from estimated tax requirements for the first two years after the date of death, and the exemption extends to certain revocable trusts treated as part of the estate.8Internal Revenue Service. Estimated Income Tax for Estates and Trusts – 2026 Form 1041-ES After that window, quarterly payments start.
Penalties That Change the Real Number
The calculation isn’t done if the return is late or the tax goes unpaid. A failure-to-file penalty runs 5% of the unpaid tax per month or partial month, up to 25%.9Internal Revenue Service. Failure to File Penalty A separate failure-to-pay penalty runs 0.5% per month on any balance still owed, also capped at 25%.10Internal Revenue Service. Failure to Pay Penalty When both apply in the same month, the filing penalty is reduced by the payment penalty, so the combined rate is 5% per month rather than 5.5%.
An accuracy-related penalty of 20% of the underpayment can apply if the fiduciary substantially understates the entity’s tax, generally meaning the reported figure was off by the greater of 10% of the correct tax or $5,000.11Internal Revenue Service. Accuracy-Related Penalty Interest also accrues on any unpaid balance. If you can’t pay on time, still file on time. The filing penalty is ten times the payment penalty, so getting the return in is always the first priority.