Overview
An income tax API for US federal and state tax calculation, built for apps that need to calculate taxes from a salary. Income Tax Calculator works by applying the official federal income tax brackets to your gross income after the standard deduction. It calculates the tax owed at each bracket level and returns a detailed breakdown including effective and marginal tax rates. Add fica=true to get take-home pay after the employee share of Social Security (capped at that year's wage base) and Medicare, including the 0.9% Additional Medicare Tax, with the FICA amounts themselves itemized on paid plans. Add state with a two-letter code (any of the 50 states or DC) to get state income tax alongside: the state's standard deduction and personal exemption are taken off the same income, its brackets applied, and any exemption credit subtracted, giving state tax, effective and marginal state rates, combined federal and state tax, and income after both. States with no wage income tax return zero. State figures come from the Tax Foundation's annual state table; phase-outs, recapture, local income taxes and credits beyond the exemption credit are not modelled, and the state's footnotes say where they apply.
Live Test Calculate Income Tax Source →
Formula
One function covers the whole catalog: the first argument names the source, the next are its inputs, and the field after them says which single value lands in the cell. Formulas covers the grammar that applies to all of them.
=VERVE("incometaxcalculator", A2, B2, "year")=VERVE.CALL("incometaxcalculator", A2, B2, "year")A2 holds income, B2 holds rate. Arguments go in that order — the same order as the table below.
With literal values
Nothing has to come from a cell — typed values work the same way.
=VERVE("incometaxcalculator", 85000, 22, "year")=VERVE.CALL("incometaxcalculator", 85000, 22, "year")Inputs
Required inputs are positional, in the order below, followed by the field. Everything else is passed as a "name", value pair after that — the same shape as SUMIFS. Premium inputs are accepted on every plan but only take effect on plans that include them.
| Input | Type | Where it goes | Description |
|---|---|---|---|
incomeRequired | number | argument 2 (A2) | Gross annual income in USD range 0–∞ |
rateRequired | number | argument 3 (B2) | Tax rate as a percentage (e.g., 22 for 22%) range 0–100 |
deductionOptional | number | "deduction", value | Optional deduction amount to subtract from income before calculating tax range 0–∞ |
Passing an option
=VERVE("incometaxcalculator", A2, B2, "year", "deduction", 14600)=VERVE.CALL("incometaxcalculator", A2, B2, "year", "deduction", 14600)What lands in your sheet
The field — the argument after the inputs — is what makes the formula resolve to one cell. Its value is a dot-path from the table below, so swapping it is how you pull a different value — one formula per column.
Seeing everything at once
Leave the field out and the formula returns the whole response instead: two columns, field name on the left and value on the right, spilling from the cell you typed in.
=VERVE("incometaxcalculator", A2, B2)=VERVE.CALL("incometaxcalculator", A2, B2)The second row's table would land on top of the first's, and every cell after the first reads #REF! (#SPILL! in Excel). Keep one per sheet, or name a field, and leave the cells below and to the right empty.
Response fields
Paths are relative to data. Each one is exactly what the field argument accepts, so swapping it is how you pull a different value into a cell. On a plan without a Premium field the cell reads #PREMIUM(field) rather than a value, so a locked field never looks like a real answer.
| Use as the field | Type | Example cell value | Description |
|---|---|---|---|
year | number | 2025 | Tax year used for calculation |
filing_status | string | single | Filing status used |
income | number | 85000 | Original gross income provided |
standardDeduction | number | 15000 | Standard deduction applied based on filing status |
taxableIncome | number | 70000 | Income after standard deduction |
totalTax | number | 10313.88 | Total federal tax owed |
effectiveRate | string | 12.13% | Effective tax rate as percentage |
marginalRate | string | 22% | Marginal tax rate (highest bracket) |
incomeAfterTax | number | 74686.12 | Take-home income after tax |
monthlyTax | number | 859.49 | Monthly tax amount (totalTax / 12) |
monthlyIncome | number | 6223.84 | Monthly take-home income (incomeAfterTax / 12) |
bracketsPremium | array[3] | Detailed breakdown of tax by bracket | |
brackets.0.ratePremium | number | 0.1 | Marginal rate for the band, as a fraction |
brackets.0.ratePercentPremium | string | 10.0% | Marginal rate for the band, formatted as a percentage |
brackets.0.rangeMinPremium | number | 0 | Income at which the band starts |
brackets.0.rangeMaxPremium | number | 11925 | Income at which the band ends |
brackets.0.taxableAmountPremium | number | 11926 | How much of the income falls inside this band |
brackets.0.taxAmountPremium | number | 1192.6 | Tax owed on the portion falling in this band |
ficaPremium | object | {…} | Employee FICA on the income as wages; present only with fica=true, null when the wage base for the year is not known |
fica.totalPremium | number | 6502.5 | Total employee FICA: Social Security plus Medicare plus Additional Medicare Tax |
fica.socialSecurityRatePremium | number | 0.062 | Employee Social Security rate, as a fraction (0.042 in 2011-2012) |
fica.socialSecurityWageBasePremium | number | 176100 | Wages above this amount owe no Social Security tax for the year |
fica.socialSecurityTaxPremium | number | 5270 | Employee Social Security tax on wages up to the wage base |
fica.medicareRatePremium | number | 0.0145 | Employee Medicare rate, as a fraction |
fica.medicareTaxPremium | number | 1232.5 | Employee Medicare tax on all wages |
fica.additionalMedicareThresholdPremium | number | 200000 | Wages above which the 0.9% Additional Medicare Tax applies for the filing status; null before 2013 |
fica.additionalMedicareTaxPremium | number | 0 | 0.9% Additional Medicare Tax on wages above the threshold |
takeHomePay | number | 68183.62 | Income after federal income tax and FICA; present only with fica=true |
monthlyTakeHomePayPremium | number | 5681.97 | Monthly take-home pay (takeHomePay / 12); present only with fica=true |
totalEffectiveRatePremium | string | 19.78% | Federal income tax plus FICA as a percentage of income; present only with fica=true |
Filling a whole column
Both platforms make one batched call for a column rather than one request per cell, and both cost the same — 2 credits per row looked up. How you write it differs, because the two runtimes batch at different points.
=VERVE("incometaxcalculator", A2:A100, B2:B100, "year")In Google Sheets, give the arguments ranges and the answers spill down from the cell you typed in. Custom functions there run synchronously and in isolation, so dragged cells cannot be coalesced — the range form is how a column becomes one call. The field is required here: a per-row two-column table has nowhere to spill. Use a full column per input (A2:A100, not A2) — a single-cell reference is read as row 1 only and the rest of the column comes back blank.
In Excel, type the formula once and fill down — no range form and none needed, because its runtime is asynchronous and the add-in coalesces the calls a fill produces into a single batched request. Do not hand VERVE.CALL a range: Excel flattens it into positional arguments, so A2:A100 arrives as a hundred separate arguments and the cell reads #ERR rather than filling.
Either way, column A holds your income values and the answers land beside them, one row each, blank rows skipped.
When a cell doesn't fill
A failed lookup returns readable text starting with #ERR rather than a spreadsheet error, because Excel cannot show a custom message on a real error — you would get a bare #VALUE! with no reason. The trade-off is that IFERROR() will not catch it; test with LEFT(cell, 4) = "#ERR" instead. Error handling covers the rest.
| Cell reads | What happened |
|---|---|
#ERR Not connected | No API key saved. Open the side panel and connect your account. |
#ERR Replace <name> with a cell or value | A preview formula was copied as-is. Swap the placeholder for a cell reference. |
#ERR No "x" in incometaxcalculator | An option name this source does not take. The message lists the ones it does. |
#ERR No data point "…" | The field path is not in the response. Check it against the table above. |
#PREMIUM(field) | The field exists but your plan does not include it. |
#ERR Out of credits | The cycle's credits are spent. Usage resets on your billing date. |
Before the formula works
The add-in reads the API key you saved once in the side panel — the key never goes in the formula, so a shared sheet does not leak it and a collaborator without access simply sees the last calculated values.
- Install the add-in for Google Sheets or Excel.
- Open the side panel and sign in, or paste a key from your dashboard.
- Type the formula above into any cell.
Use cases
- Job Offer Evaluation
- When weighing multiple job offers, candidate compensation portals calculate net take-home pay and federal tax obligations across different filing statuses.
- Payroll Withholding Estimation
- HR platforms estimate employee annual federal tax liability and monthly deductions directly from gross salary inputs to forecast withholdings.
- Retirement Distribution Modeling
- To model retirement drawdowns, financial advisors project changes in effective and marginal rates as client taxable distributions shift across tax bands.
- Custom Rate Invoicing
- Compute estimated tax obligations and remaining net earnings for freelance contracts using custom tax percentages and project deductions.
Other ways to use Calculate Income Tax
Set up Calculate Income Tax on VerveSheets, or reach the same source a different way. Your VerveSheets account and credits work on all of them — one key, one balance.
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