Tools/Bunching model
Tax year 2026 rules
The models

Give the same.Deduct more.

Compresses several years of giving into one, and shows what clears the threshold instead of quietly falling under it. Three rules changed in 2026, and all three moved in favor of doing this deliberately.

The model

Your numbers, both ways.

Your inputs Recalculates as you type
Filing status
Income and giving
$

Line 11 of your 1040. Assumed steady across the cycle.

$

Cash and appreciated securities combined.

Your other itemized deductions
$

Income plus property tax, before the cap is applied.

$

Deductible interest on up to $750,000 of acquisition debt.

$

Medical above 7.5% of AGI, investment interest, and the rest.

Years to bunch into one

A donor advised fund is what makes the long cycles practical.

Result 3-year cycle
Federal tax saved across the cycle

$3,264

Same total given, same charities, different timing.

Additional deduction captured$13,600
Benefit rate on that deduction24%
Years you itemize1 of 3, not 3 of 3
Total given, either way$45,000

The 2026 floor. Only giving above 0.5% of AGI is deductible now. Spreading pays that toll every year; bunching pays it once.

Itemizable deductions by year under both approaches, against the standard deduction
Bunched Spread evenly ——  Standard deduction $32,200

Bars show total itemized deductions each year. A bar below the line is a year the standard deduction wins.

Hypothetical illustration, federal income tax only. Not a recommendation, a projection, or advice about your situation.

The assumptions

Every number this uses,in one place.

Each one is editable. Change it and the model, the table and the chart all move with you.

Standard deduction
$

2026, married filing jointly. IRS Rev. Proc. 2025-32. Changes when you change filing status. Override it if you are 65 or older or blind.

SALT cap applied
$

2026 cap under OBBBA. Phases down by 30 cents per dollar of AGI above $505,000, with a $10,000 floor. Recalculated from your AGI.

Charitable AGI floor
%

New for 2026 under IRC §170(b)(1)(I). Itemizers deduct only giving above this share of AGI. This is the rule that made bunching more valuable than it was last year.

Non-itemizer charitable deduction
$

New for 2026 under §170(p). Available in your standard deduction years, for cash given directly to public charities. Gifts to a donor advised fund do not qualify.

Cap on itemized deduction value
%

Top-bracket filers get 35 cents per dollar of itemized deductions, not 37. Applied as the statutory 2/37 reduction. Status: not triggered at your income.

Marginal rate at these numbers
%

Derived, not entered. The model runs your taxable income through the full 2026 bracket schedule in both scenarios rather than applying one flat rate.

Year by year

Where the difference actually comes from.

Both paths, side by side 3-year cycle
SPREAD EVENLY BUNCHED
Year GivenDeductionFederal tax GivenDeductionFederal tax

Deduction shown is the greater of the standard deduction or total itemized deductions after the charitable floor, the SALT cap, and where applicable the top-bracket limitation. Federal ordinary income tax only. State tax, AMT, the net investment income tax, QBI, and credits are not modeled.

The fine print, up front

What this doesn't do.

State tax

It doesn't know your state

California does not conform to the federal standard deduction and taxes at its own schedule. In a high-tax state the bunching answer can move meaningfully once state tax is layered in.

Income timing

It assumes a steady income

The real opportunity is usually bunching into the year your income spikes, not an average year. If you have a liquidity event, an exercise window, or a bonus year coming, that year is the answer and this model won't find it for you.

Gift type

It treats all gifts as cash

Giving appreciated stock instead avoids the capital gains tax entirely and clears the floor faster. That is usually the larger number, and it is not in here.

AGI thresholds

It stops at the deduction

Timing giving changes AGI-linked thresholds around you: the SALT phase-down, the net investment income tax, IRMAA surcharges. Those interactions are real and not modeled.

Ceilings

Carryforwards can play a role

Giving above 60% of AGI in cash, or 30% in appreciated property, carries forward five years. A large bunch can breach those ceilings, which changes the timing of the benefit.

Scope

It isn't advice

This is arithmetic on figures you typed. It is not a recommendation to give, to change your giving, or to open any account. Talk to your tax adviser before you act on it.

Prepared under federal tax rules in effect for tax year 2026, including the One Big Beautiful Bill Act (P.L. 119-21) and IRS Rev. Proc. 2025-32. Tax law changes. Figures should be confirmed against current authority before you rely on them. This tool produces a hypothetical illustration for general educational purposes only. It does not account for your complete financial circumstances, is not tax or legal advice, and results are not indicative of any actual or future outcome. Carrara Capital, LLC does not provide tax or legal advice. Consult your own tax adviser or attorney before acting.

Next

Bring your output.We'll pressure-test it.

The version of this we run for clients layers in your state, your appreciated positions, and the year your income is actually going to spike.

CARRARAWealth Management

A fee-only fiduciary in Los Angeles, built for people who take their financial wellbeing seriously.

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Carrara Capital, LLC, doing business as Carrara Wealth Management, is an investment adviser registered with the State of California (CRD 340803). Registration does not imply a particular level of skill or training. Nothing on this page is investment, tax, or legal advice, an offer to buy or sell any security, or a recommendation. The calculators and diagrams shown produce hypothetical illustrations for educational purposes and are not indicative of any client's experience or of future results. An advisory relationship begins only upon execution of a written agreement by both parties.