MathBench

Tithing Calculator

Enter your pay and the percentage you give, and see the tithe per paycheck and per year — on gross or take-home — plus what it truly costs you once tax relief is counted, which is usually a smaller number than people expect.

Educational estimates only. This calculator is for planning and education. It is not financial, tax, or investment advice, and results may differ from what a lender, broker, or the IRS calculates for your situation. Confirm important decisions with a qualified professional.

The tithe

Your tax situation (sets what the giving is worth back — leave as-is for a simple estimate)

Your tithe

—

—for the year
—what it costs you after tax
—tax you no longer owe
—take-home before giving
—left after giving
—marginal tax rate

Where the money goes

Gross or take-home

If the percentage changed

Are you on pace this year?

Years ahead — what giving adds up to

How this calculator works

The calculator starts with a year of pay — either an hourly rate times your hours and weeks, with overtime added at its own multiple, or a salary taken as given. It applies your percentage to that, divides by how often you're paid, and reports the figure you'd actually write on each check.

Then it does the part most tithing calculators skip: it works out what the giving costs you after tax. Charitable giving reduces your tax bill only in specific circumstances, and usually by far less than your tax bracket suggests — because the standard deduction was already yours for free, and only the amount by which itemizing beats it is genuinely being bought with your gift. The "where the money goes" table walks your whole year from gross pay down to what's left, and the note beneath it explains in plain words why your relief came out the size it did.

Tithing on take-home pay is handled properly rather than approximated. That calculation is circular — your take-home depends on your tax, your tax depends on your giving, your giving depends on take-home — so the answer is found by iterating until it stops moving. The comparison table shows both bases at once, because the gross-versus-net question is the one people most want a number for.

The formula

Gross pay      hourly: rate × hours × weeks + rate × OT multiple × OT hours × weeks
               salary: as entered

The tithe      on gross:     tithe = percent × gross
               on take-home: tithe = percent × take-home, solved by iteration
                             (take-home itself depends on the tithe)
Each paycheck  tithe ÷ paychecks a year, rounded up if you chose to

Tax           AGI      = gross − health premiums − retirement contributions
              giving   = tithe + other giving
              itemized = other itemized + max(0, giving − 0.5% × AGI)
              deducted = itemized, or standard + min(giving, allowance)
              taxable  = AGI − deducted
              income tax = brackets applied band by band to taxable
              payroll  = 6.2% to the wage base + 1.45% on all wages
                         (+0.9% above the surcharge threshold)

What it costs  relief = tax without the tithe − tax with it
               cost   = tithe − relief

The 2026 federal figures are from IRS Revenue Procedure 2025-32, as summarized in the IRS newsroom release "IRS releases tax inflation adjustments for tax year 2026"(irs.gov): a $16,100 standard deduction filing single, $32,200 filing jointly, and $24,150 as head of household, with the seven brackets from 10% to 37%. The Social Security wage base of $184,500 comes from the Social Security Administration's 2026 fact sheet. Two charitable rules new for 2026 under the One Big Beautiful Bill Act are modeled: a deduction of up to $1,000 (single) or $2,000 (joint) for cash giving by people who take the standard deduction, and a floor equal to 0.5% of adjusted gross income under itemized giving. All figures verified against those sources on 17 August 2026.

Worked example

$28 an hour, 40 hours a week, 52 weeks, filing single, tithing 10% of gross, paid every two weeks — the calculator's default:

  1. Gross pay: 28 × 40 × 52 = $58,240
  2. The tithe: 10% of gross = $5,824 a year, which over 26 paychecks is $224.00 each
  3. Deductions: the $16,100 standard deduction, plus $1,000 of giving — the allowance caps there, so the other $4,824 given deducts nothing. Total $17,100
  4. Taxable income: 58,240 − 17,100 = $41,140, and the brackets charge 10% on the first $12,400 then 12% on the rest = $4,688.80 of federal income tax
  5. Payroll tax: 6.2% + 1.45% of $58,240 = $4,455.36
  6. Take-home before giving: 58,240 − 4,688.80 − 4,455.36 = $49,095.84
  7. Tax relief on the gift: 12% of the $1,000 that actually deducted = $120, so the tithe truly costs $5,704

That last line is the point of the tool. A $5,824 gift saved $120 in tax — about 2%, not the 12% bracket — because the standard deduction was already larger than anything itemizing could offer. Switch "reckoned on" to take-home and the same person gives $188.83 a paycheck, or $4,910 a year: choosing gross over take-home costs $914 more annually.

Assumptions & tips

  • Don't give for the deduction. The arithmetic here exists to remove a surprise at tax time, not to argue for or against a number. For most households the tax saving on a tithe is small or zero, and that changes nothing about whether to give.
  • The standard deduction is why relief looks small. Everyone gets it free. Giving only reduces tax to the extent that itemizing beats it, so the first several thousand dollars of giving typically buys nothing — the note under the table spells out where your own line falls.
  • Bunching is the usual workaround. Some households give two years' worth in one calendar year so that year clears the standard deduction, then take the standard deduction the next. Worth discussing with a tax professional before rearranging your giving.
  • Rounding up always gives a little more. Rounding $224.00 up to the nearest $25 makes it $225.00 a check — an extra $26 a year. Convenient, and never less than the exact figure.
  • What this leaves out. Credits of any kind, dependents, a second earner's separate withholding, self-employment tax, income that isn't wages, carry-forward of giving above the AGI limits, and state rules beyond one flat rate. It also doesn't model the new 35% cap on the value of itemized deductions that applies in the top 37% bracket, so very high earners should treat the relief figure as slightly optimistic.
  • Withholding isn't the same as tax. What comes out of your check each period is your employer's estimate; what you actually owe is settled on the return. Expect the two to differ.

Frequently asked questions

Should a tithe be calculated on gross or take-home pay?

This is the oldest disagreement in tithing, and it is a question of conscience rather than arithmetic — no calculator settles it. What a calculator can do is show what the choice is worth. On a $58,240 salary, a 10% tithe on gross is $5,824 a year while 10% of take-home is $4,910, a difference of about $914. The tool works out both at once so you can see the number rather than guess at it. Many people who tithe on gross describe it as giving from the whole harvest; many who tithe on take-home point out that tax was never theirs to give.

Why is my tax saving so much smaller than my tax bracket?

Because the standard deduction was already free. Giving only reduces your tax to the extent that itemizing beats the standard deduction, so the first several thousand dollars of charitable giving often buys nothing at all. A married couple earning $250,000 who gives $25,000 and has $12,000 of other itemized deductions saves about $852 in tax — roughly 3.4% of the gift, not the 24% their bracket might suggest. That gap surprises almost everyone, and it is the main reason this calculator exists.

What changed about charitable deductions in 2026?

Two things, both from the One Big Beautiful Bill Act, and both matter to people who give a full tithe. First, people who take the standard deduction can once again deduct cash giving — up to $1,000 filing single or $2,000 filing jointly (gifts to donor-advised funds do not count). Second, people who itemize now face a floor: the first 0.5% of adjusted gross income of their giving is not deductible at all. On $250,000 of income that is $1,250 of a tithe that simply stops counting. Both rules are built into this calculator.

Does the calculator handle tithing on take-home pay correctly?

Yes, and it is trickier than it looks. Take-home depends on your tax, your tax depends on what you gave, and what you gave depends on take-home — so the answer is circular and cannot be written as a single formula. The calculator solves it by iterating until the number stops moving, which happens within a few passes, and the result is self-consistent to the cent: the tithe it reports really is your chosen percentage of the take-home pay it reports.

Is this tax advice?

No. It is an estimate of one household's federal position from a handful of inputs, and it deliberately leaves out most of what a real return contains: credits, dependents, a second earner's withholding, self-employment income, capital gains, carry-forward of giving above the AGI limits, and every state rule beyond a single flat rate. Use it to plan and to understand the shape of the decision, then check anything that matters with someone who signs returns.

Sources

  1. Rev. Proc. 2025-32 — Internal Revenue Service, 2025. irs.govSection 4 supplies the 2026 figures the tax engine carries: the seven rate tables under §1(j) and the standard deduction under §63 — $16,100 single, $32,200 married filing jointly, $24,150 head of household.
  2. IRS releases tax inflation adjustments for tax year 2026, including amendments from the One, Big, Beautiful Bill — Internal Revenue Service newsroom, 2025. irs.govThe plain-language summary of the same brackets and standard deductions, used to cross-check the figures read out under the results.
  3. Publication 15 (2026), (Circular E), Employer's Tax Guide — Internal Revenue Service, 2026. irs.govThe payroll-tax line: 6.2% Social Security to the $184,500 wage base for 2026, and 1.45% Medicare on all wages.
  4. Topic no. 560, Additional Medicare tax — Internal Revenue Service. irs.govThe extra 0.9% the payroll calculation adds on wages above the filing-status threshold.
  5. Public Law 119-21, sections 70424 and 70425 — U.S. Government Publishing Office, enacted 4 July 2025. govinfo.govThe enacted text behind both 2026 charitable rules modeled here — §70424 raises the non-itemizer deduction under §170(p) to $1,000 ($2,000 joint), and §70425 adds the floor allowing itemized giving only above 0.5% of the taxpayer's contribution base.
  6. Topic no. 506, Charitable contributions — Internal Revenue Service. irs.govConfirms that from 2026 a taxpayer who does not itemize may deduct up to $1,000 ($2,000 filing jointly) of cash gifts — the allowance the calculator caps at.
  7. Publication 526, Charitable Contributions — Internal Revenue Service. irs.govWhat counts as a deductible gift, which organizations qualify, and the AGI percentage limits and carry-forward rules this estimate deliberately leaves out.

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