Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Extra tax savings from bunching
$1,632
Total deduction value, bunched
$22,656
Total deduction value, giving annually
$21,024
Lump sum contributed to DAF
$24,000
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How to use this
- 1Enter amount you'd normally give per year ($).
- 2Enter years of giving to bunch together.
- 3Enter other itemizable deductions per year (salt cap, mortgage interest) ($).
- 4Enter standard deduction for your filing status ($).
- 5Enter marginal tax rate (%).
- 6Read your extra tax savings from bunching on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Since the standard deduction roughly doubled in 2018, many households who used to itemize now take the standard deduction every year, getting zero marginal tax benefit from modest annual charitable gifts. Bunching solves this: instead of giving, say, $8,000 a year, you contribute $24,000+ into a donor-advised fund in a single year, itemize that year to capture the full deduction, then take the standard deduction in the following lean years while the DAF still pays out grants to charities on your normal schedule. This calculator compares total taxes paid over a multi-year cycle under 'give every year' (mostly wasted deduction) versus 'bunch into a DAF' (one big itemized year plus standard-deduction years), using your marginal rate and the standard deduction for your filing status.
Worked example
Using the values the calculator loads with:
Inputs
- Amount you'd normally give per year: 8000 $
- Years of giving to bunch together: 3
- Other itemizable deductions per year (SALT cap, mortgage interest): 12000 $
- Standard deduction for your filing status: 29200 $
- Marginal tax rate: 24 %
Results
- Extra tax savings from bunching: $1,632
- Total deduction value, bunched: $22,656
- Total deduction value, giving annually: $21,024
- Lump sum contributed to DAF: $24,000
What each field means
Inputs
- Amount you'd normally give per year ($)
- The amount you'd normally give per year used in the calculation, measured in $. Starts at 8000 $ so you have a working example on load.
- Years of giving to bunch together
- The years of giving to bunch together used in the calculation. Starts at 3 so you have a working example on load. Accepted range: 2–6.
- Other itemizable deductions per year (SALT cap, mortgage interest) ($)
- The other itemizable deductions per year (salt cap, mortgage interest) used in the calculation, measured in $. Starts at 12000 $ so you have a working example on load.
- Standard deduction for your filing status ($)
- The standard deduction for your filing status used in the calculation, measured in $. Starts at 29200 $ so you have a working example on load.
- Marginal tax rate (%)
- The marginal tax rate used in the calculation, measured in %. Starts at 24 % so you have a working example on load. Accepted range: 0–50 %.
Results
- Extra tax savings from bunching
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total deduction value, bunched
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total deduction value, giving annually
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Lump sum contributed to DAF
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What exactly is a donor-advised fund?
It's an investment account, sponsored by a custodian like Fidelity Charitable or Schwab Charitable, that you fund with an irrevocable charitable contribution. You get the tax deduction the year you contribute, the money can be invested and grow tax-free inside the fund, and you recommend grants out to actual charities on whatever timeline you want afterward.
Why does bunching only help if I'd otherwise take the standard deduction?
If your other itemized deductions already exceed the standard deduction every year, you're already getting full value from each dollar of giving, and bunching adds little beyond a minor time-value-of-money benefit. Bunching's real power is converting years of 'wasted' giving (deduction below the standard threshold) into one year where the deduction clearly clears that bar.
Can I contribute appreciated stock instead of cash?
Yes, and it's usually better. Donating appreciated shares held over a year lets you deduct the full fair market value while avoiding capital gains tax entirely on the appreciation, which cash contributions can't do.
Do I have to grant out the money in the same year I contribute?
No. You get the deduction in the contribution year regardless of when you actually direct grants to charities, which is what allows you to keep your charities' cash flow steady even while bunching your tax deduction into one year.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
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Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Donor-Advised Fund Bunching Tax Savings Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/daf-bunching-tax-savings
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/daf-bunching-tax-savings" target="_blank" rel="noopener">Donor-Advised Fund Bunching Tax Savings Calculator — RevenueLab</a> (2026).</p>
Source: [Donor-Advised Fund Bunching Tax Savings Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/daf-bunching-tax-savings) (2026).