About the Charitable Bunching Calculator
With a standard deduction of $32,200 for married couples and $16,100 for single filers in 2026, many donors get no tax benefit from their charitable gifts because their itemized deductions never beat the standard deduction. Bunching means making two or three years’ worth of gifts in one year — usually by contributing to a donor-advised fund (DAF) — so you itemize in that year and take the standard deduction in the others. This calculator compares the two strategies over a full cycle.
It applies the 2026 rules from the One Big Beautiful Bill Act: itemized charitable deductions only count above 0.5% of AGI; non-itemizers can deduct up to $1,000 ($2,000 joint) of cash gifts made directly to public charities (contributions to a DAF do not qualify); cash gifts are limited to 60% of AGI; and for taxpayers in the 37% bracket itemized deductions are reduced by 2/37 of the lesser of those deductions and taxable income above the 37% threshold, which the calculator simplifies to a 35/37 haircut on all itemized deductions.
Enter your yearly giving, other itemized deductions (state and local taxes up to the SALT cap, mortgage interest and so on), AGI and marginal rate. The calculator assumes the same income and other deductions every year, a flat marginal rate, and that in non-bunching years you give nothing new out of pocket while the DAF makes grants to your charities.
With the default inputs, the extra tax saved per cycle by bunching is $1,111.00. Change any value above to recalculate instantly.
How to use the charitable bunching calculator
- 1Choose your filing status.
- 2Enter how much you normally give to charity each year.
- 3Enter your other itemized deductions and your AGI.
- 4Pick your marginal tax rate and how many years to bunch.
- 5Compare total deductions and read the extra tax saved by bunching.
Formula and method
Giving the same amount every year, each year you take the larger of itemizing (other deductions plus gifts above the 0.5%-of-AGI floor) or the standard deduction plus the new non-itemizer deduction for cash gifts to public charities. With bunching, you contribute n years of gifts to a donor-advised fund in year one and itemize, then take the standard deduction (or itemize other deductions if larger) in the remaining years. DAF contributions do not count toward the non-itemizer deduction.
The difference in total deductions over the cycle is multiplied by your marginal rate to estimate the extra tax saved. Cash gifts are capped at 60% of AGI. For the 37% bracket, itemized deductions are scaled by 35/37 to reflect the new limit on their value. The model assumes a constant marginal rate and the 2026 standard deduction in every year.
- n
- Number of years of giving bunched into one year
- other
- Non-charitable itemized deductions
- rate
- Federal marginal tax rate
Worked examples
Married couple giving $10,000 a year, bunching 2 years
Giving annually, itemizing gives $22,000 + $9,250 = $31,250, so they take $32,200 + $2,000 = $34,200 each year ($68,400). Bunching $20,000 into a DAF gives $41,250 in year one and $32,200 in year two ($73,450). The extra $5,050 saves $1,111 at 22%.
Single donor, $6,000 a year, bunching 3 years
Giving yearly, itemizing ($12,000 + $6,000 − $500 floor = $17,500) narrowly beats $16,100 + $1,000, so three years total $52,500. Bunching $18,000 gives $12,000 + $17,500 = $29,500 in year one plus $16,100 in each of the next two years ($61,700): $9,200 more deductions and $2,208 of tax saved.
Already itemizing every year
With $40,000 of other deductions this couple itemizes every year, so gifts are already deductible. Bunching only gains by meeting the $750 0.5%-of-AGI floor once instead of twice — $750 × 22% = $165 over two years.
Frequently asked questions
What is charitable bunching?+
Bunching means concentrating several years of charitable giving into a single tax year so your itemized deductions exceed the standard deduction in that year, then taking the standard deduction in the following years.
Why use a donor-advised fund for bunching?+
A donor-advised fund lets you take the full deduction in the year you contribute while recommending grants to charities over the following years, so your favorite charities keep receiving steady support.
How did the 2025 tax law change charitable deductions?+
From 2026, itemized charitable gifts are only deductible above 0.5% of AGI, top-bracket taxpayers get at most a 35% benefit, and non-itemizers can deduct up to $1,000 ($2,000 joint) of cash gifts to public charities, though not to donor-advised funds.
Can I bunch with appreciated stock?+
Yes, and it is often better: donating long-term appreciated shares to a DAF avoids capital gains tax and gives a deduction for fair market value, limited to 30% of AGI with a five-year carryforward for any excess.
Is bunching worth it if I already itemize?+
Usually not much. If your deductions beat the standard deduction every year, each gift is already deductible. Bunching helps most when your other itemized deductions are close to, but below, the standard deduction.
Tax results are estimates based on published rules and simplified assumptions. They are not tax advice — check official guidance or a tax professional for your situation.
Sources
- IRS — Tax inflation adjustments for tax year 2026 (standard deduction)
- IRS — One Big Beautiful Bill provisions (non-itemizer charitable deduction)
- 26 U.S. Code § 170 — Charitable contributions (0.5% floor)
- 26 U.S. Code § 68 — Limitation on itemized deductions (2/37 rule)
- IRS — Publication 526, Charitable Contributions