Charitable Bunching at $31,500: 2-Year vs 1-Year Math

The decision: Mark and Priya, $20,000 a year to charity

Mark and Priya file jointly in Ohio. Combined income puts them squarely in the 24% federal marginal bracket (MFJ: $206,701–$394,600 for 2026). They give $20,000 a year — $12,000 to their church, $8,000 split across two nonprofits — and they have done it the same way for years: write the checks monthly, deduct nothing extra.

Here is the problem they never noticed. Their other itemizable deductions are $10,000 of state-and-local tax (capped) and $4,000 of mortgage interest. Add their $20,000 of giving and their itemized total is $34,000 — barely over the $31,500 standard deduction. So they itemize, but only $2,500 of their deductions do any work above the standard amount. Their $20,000 of generosity buys them roughly $600 of tax savings (24% × $2,500). The other $17,500 of giving is, for tax purposes, invisible.

The fix costs nothing and changes no charity’s funding: instead of $20,000 every year, they give $40,000 in year one and $0 in year two (front-loading year two’s gifts into a donor-advised fund in December of year one, then granting them out on the normal schedule). Same $40,000 over two years. Same checks to the same charities. Different calendar. Below is the dollar difference.

Why $31,500 is the number that controls everything

The 2026 standard deduction is $31,500 for MFJ, $23,625 for head of household, and $15,750 for single filers (IRS Rev. Proc. 2025-32). You only benefit from charitable giving on your federal return if you itemize — and you only itemize when your total itemized deductions beat that number. Every dollar of itemized deductions below the standard deduction is wasted, because you would have gotten the standard amount for free.

For most households the itemized stack has three parts:

• SALT: state and local income/sales tax plus property tax, capped at $10,000 (IRC §164(b)(6)). Most homeowners in tax states hit the cap, so this is a fixed $10,000 for them.
• Mortgage interest: deductible on up to $750,000 of acquisition debt (IRC §163(h)). Declines every year as the loan amortizes; many paid-down or no-mortgage households have little or none.
• Charitable gifts: the one lever you fully control on timing (IRC §170). Cash to public charities is deductible up to 60% of AGI.

Because SALT is capped and mortgage interest is fixed by your loan, charitable giving is the only deduction whose timing you can move. That is what bunching exploits.

Run the gap calculation for your own household. Take $31,500, subtract your SALT (most homeowners in tax states: a flat $10,000) and your mortgage interest. The remainder is the charitable giving you need in a single year just to reach the breakeven line where itemizing ties the standard deduction. For Mark and Priya that gap is $31,500 − $14,000 = $17,500. Their $20,000 of annual gifts clears it by only $2,500 — which is exactly why their flat schedule wastes almost all of their giving. Double the gift in one year and the gap is crushed; skip the next year and the standard deduction covers you for free.

The math: flat $20K/year vs. bunched $40K every other year

Assume Mark and Priya’s fixed deductions are $10,000 SALT + $4,000 mortgage interest = $14,000 of non-charitable itemized deductions per year. Standard deduction: $31,500. Here is the two-year cycle each way.

Read the bottom rows carefully. Over two years the flat schedule claims $68,000 of deductions. The bunched schedule claims $85,500 — $17,500 more — for the exact same $40,000 of giving. At a 24% marginal rate that is $4,200 of additional federal tax savings every two-year cycle, or about $2,100 a year, that the flat schedule simply leaves on the table.

Where does the $17,500 come from? In the flat case, the off-year benefit above the standard deduction is small ($34,000 − $31,500 = $2,500 of useful deduction, twice). In the bunched case, the big year captures the full $54,000 and the small year defaults to the $31,500 standard floor — you get the standard deduction for free in year two on top of the year-one itemizing. Bunching lets you collect the standard deduction in the off year and a fat itemized deduction in the on year.

The bracket matters: why 24% beats 22%

The dollar value of every deduction equals your marginal rate — the rate on your last dollar of income. The same $17,500 of extra deductions is worth:

• 22% bracket (MFJ $96,951–$206,700): $17,500 × 22% = $3,850 per cycle.
• 24% bracket (MFJ $206,701–$394,600): $17,500 × 24% = $4,200 per cycle.
• 32% bracket (MFJ $394,601–$501,050): $17,500 × 32% = $5,600 per cycle.

There is a second, sharper play here: if your income straddles a bracket line, bunch in the year you are in the higher bracket. A big itemized deduction is worth more when it knocks income out of a 32% slice than a 24% slice. If you expect a high-income year (a bonus, an RSU vest, a business sale) followed by a lower one, put the bunch in the high year.

The donor-advised fund makes the calendar invisible to charities

The objection to bunching is practical: your church and your local nonprofits count on steady annual support, and a feast-or-famine pattern hurts them. The donor-advised fund (DAF) solves this entirely.

1. Year one: contribute the full bunched amount ($40,000) to a DAF in December. You take the entire $40,000 deduction in year one because the gift to the DAF is complete and irrevocable when made (IRC §170).
2. Years one and two: recommend grants out of the DAF to your charities on your normal monthly or annual schedule. The charities see no change in their funding rhythm.
3. Bonus: contribute appreciated stock instead of cash. You deduct fair market value and skip the capital gains tax you would owe on selling it — a separate stack of savings on top of the bunching benefit.

From the charity’s seat, nothing changed. From your tax return, you front-loaded a deduction into a year where it cleared the $31,500 hurdle. That is the whole trick.

Timing inside the year matters too. The deduction lands in the tax year the gift is complete, not the year the DAF grants the money out. A contribution must clear before December 31 to count for that year — for appreciated stock, allow several business days for the transfer to settle, so initiate it by mid-December at the latest. A check is treated as given when mailed (postmark rules), but a wire or stock transfer counts only when received. Do not wait until December 31 to fund a stock-based bunch; a settlement that slips into January pushes the entire deduction into the wrong year.

What most people get wrong

Myth: “I give to charity, so I get a tax break.” Roughly 9 in 10 households take the standard deduction since the TCJA nearly doubled it. If you are one of them, your charitable giving currently produces zero federal tax benefit — not a reduced benefit, zero. The deduction exists only above the standard deduction line, and you never cross it. Bunching is how you cross it.

Myth: “Bunching means giving more.” It is the opposite of that. You give the same total — $40,000 over two years either way. You change when, not how much. The IRS does not care that you front-loaded; the deduction follows the year the gift was made.

Myth: “The 60% AGI limit will cap my bunched gift.” Cash gifts to public charities are deductible up to 60% of AGI (IRC §170(b)). A couple with $250,000 of AGI can deduct up to $150,000 of cash gifts in one year — a $40,000 bunch is nowhere near the ceiling. If you ever do exceed the limit, the excess carries forward for five years; you do not lose it.

Retirees: bunch, QCD, or both

If you are 70.5 or older and have a traditional IRA, the calculus shifts. A qualified charitable distribution (QCD) lets you send up to $108,000 per person in 2026 directly from your IRA to charity, excluded from income entirely — and it works even if you take the standard deduction, because it never enters AGI in the first place (IRC §408(d)(8)). Lowering AGI also helps with Medicare IRMAA tiers (the 2026 base premium stays at $185/month only while single MAGI is at or under $103,000) and the taxation of Social Security.

Bunching, by contrast, only helps if you itemize. So the rule of thumb for retirees:

A QCD also satisfies your required minimum distribution dollar-for-dollar, so a 73-year-old who must take an RMD anyway can route it straight to charity and never pay tax on it. That is often a stronger move than bunching for IRA-heavy retirees.

The decision lever

Run three lines on a napkin before December. Add your SALT (max $10,000), your annual mortgage interest, and your annual charitable giving. If that sum lands within a few thousand dollars of $31,500 — above or below — you are the exact profile bunching was built for, and you are probably leaving $2,000+ a year unclaimed. Take next year’s giving, write the check this December into a donor-advised fund, itemize the doubled amount, and take the standard deduction next year. Same charities, same total, a four-figure check back from the IRS for changing nothing but the calendar.