▣ VERIFICATION KIT

US Sales Tax Calculator API

What it does

Sales Tax Calculator lets you add or extract U.S. sales tax from a single amount or a cart of items. Send a tax rate directly with taxPercent, look up the base state rate with state, or resolve the state from an exact zip when the ZIP code maps cleanly.

Use mode: add to calculate tax, subtotal, and total for an amount or an items array. For itemized carts, each item can include qty, name, price, and taxable; you can also apply discountPct, shipping, and shippingTaxable. Use mode: extract when you already have a tax-inclusive amount and need the pre-tax value and tax amount separated.

The response is plain JSON, with the computed sales tax result and any ZIP lookup details when you use zip. That makes it useful for checkout logic, invoice generation, quote tools, and internal pricing calculators where you need a consistent tax estimate without wiring in a full tax engine.

Sales Tax Calculator is designed for state-level calculation only. It does not guess local city, county, or district add-ons, so for addresses where those matter you should provide taxPercent yourself or use a known state rate.

POST

Calculate sales tax on an amount, adding or extracting tax, with US state base-rate lookup

https://api.eu.apyhub.com/freedailypro/us-sales-tax-calculator/sales-tax

QUICKSTART

GUIDE

Quickstart

Calculate sales tax from a simple amount and state lookup.

curl -X POST "https://api.eu.apyhub.com/freedailypro/us-sales-tax-calculator/sales-tax" \
  -H "apy-token: $APY_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "state": "TX",
    "amount": 100
  }'

What you'll get back

Returns a JSON object with no declared fields in the output schema.

{
  "result": {
    "taxAmount": 6.25,
    "total": 106.25,
    "net": 100,
    "amount": 100,
    "ratePct": 6.25,
    "rateSource": "US state base rate (local taxes excluded)",
    "state": "Texas",
    "stateBaseRatePct": 6.25,
    "averageCombinedRatePct": 8.2,
    "ratesAsOf": "Tax Foundation, 1 July 2026",
    "ratesAsOfDate": "2026-07-01",
    "ratesCheckedOn": "2026-10-30",
    "ratesAgeDays": 134,
    "ratesStale": false,
    "taxYear": 2026,
    "dataStatus": "estimate",
    "notes": [
      "Rate used: Texas STATE base rate 6.25%. Local (city, county, district) sales taxes are not included; the average combined rate is 8.2% (reference only, not applied). For an exact local rate send taxPercent."
    ],
    "disclaimer": "Estimate for information only. Not tax, legal or financial advice; check the figures with the tax authority or a qualified adviser."
  }
}

TRY ITLIVE · 10 ATOMS

API key

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body*

Send either amount or items, not both. If both are sent, items is used and amount is ignored. Send at least one rate source: taxPercent, state, or an exact zip.

zip

US ZIP code, 5 digits or ZIP+4. Used to find the state. A rate is applied only where it is exact: 0% for DE, NH and OR, or the state rate for states with no local add-on. For any other ZIP, or a ZIP that can fall in more than one state, the call returns a 400 asking for state or taxPercent.

mode

add (default) adds tax on top of the amount. extract treats the amount as tax-inclusive and returns the net and the tax in it. extract cannot be used with items.

items

A cart of 1 to 100 items. Add mode only. A response adds cart with taxable and exempt subtotals, tax, total, steps and lines.

items-1*

price*

Price of one unit.

About this endpoint

What it does

Calculates sales tax for a US amount using either a provided tax rate, a US state lookup, or an exact ZIP lookup when available. It supports both single-amount and multi-item cart calculations, with optional shipping and discount handling in item mode.

Request Body

Parameter	Type	Mandatory	Description
zip	String	No	US ZIP code (5 digits or ZIP+4). Used to find the state. The rate is filled in only where it is exact: 0% for DE, NH and OR, or the state rate for states with no local add-on in the Tax Foundation midyear 2026 table. For any other state no rate is guessed; the response's `zip.message` says so, and you send `taxPercent` or `state`.
mode	ENUM	No	Allowed values: `add`, `extract`.
items	Object Array	No	Several items, used in `add` mode only. Each item may include: `qty` (integer, minimum 1, maximum 9007199254740991), `name` (string), `price` (number, minimum 0, required), `taxable` (boolean, default `true`). Maximum 100 items, minimum 1 item. Response adds `cart` with taxable and exempt subtotals, tax, total, steps and lines.
items[].qty	Integer	No	Quantity for the item, minimum 1, maximum 9007199254740991.
items[].name	String	No	Item name.
items[].price	Number	Yes	Item price, minimum 0.
items[].taxable	Boolean	No	Marks the item exempt when `false`. Default `true`.
state	String	No	US state code (two-letter code such as `TX`, or the full name; `DC` included). Looks up the state base sales tax rate only (Tax Foundation, 1 July 2026). Local city, county, and district rates are not included.
amount	Number	No	Amount to tax, or the tax-inclusive amount in `extract` mode. Required unless `items` is sent. Minimum 0.
shipping	Number	No	Shipping charged when using `items`. Minimum 0.
taxPercent	Number	No	Tax rate in percent. Required unless `state` or an exact `zip` is sent. Takes priority over `state`. Minimum 0, maximum 100.
discountPct	Number	No	With `items`: percentage discount on every line. Minimum 0, maximum 100.
shippingTaxable	Boolean	No	With `items`: `true` adds shipping to the taxable amount. Default `false` (rules differ by state, so you choose).

Response

The endpoint returns a JSON object with the result under result. Which fields appear depends on how you called it, as shown in the last column.

Field	Type	Description	Returned
taxAmount	Number	The sales tax, rounded to the cent (half a cent rounds up). With `items`, this is the tax for the whole cart.	Always
total	Number	Net plus tax. With `items`, the whole cart including exempt items, discount and shipping.	Always
net	Number	The amount before tax. With `items`, the whole cart after discount and including shipping.	Always
amount	Number	The amount you sent, or with `items` the sum of the item prices before any discount.	Always
ratePct	Number	The rate that was applied, in percent.	Always
rateSource	String	Where the rate came from, for example `US state base rate (local taxes excluded)` or `taxPercent sent by the caller`.	Always
state	String	The state used.	When the rate came from `state` or `zip`
stateBaseRatePct	Number	The state base rate, in percent.	When a state was used
averageCombinedRatePct	Number	The average combined state and local rate for the state, for reference only. It is not applied.	When a state was used
zip	Object	The state found from the ZIP, whether a rate was applied (`rateApplied`), a message, and the source.	When `zip` was sent
ratesAsOf	String	Who published the rate table and its date.	Always
ratesAsOfDate	String	Date of the rate table (`YYYY-MM-DD`).	When a state rate was used
ratesCheckedOn	String	Date the table was last checked (`YYYY-MM-DD`).	When a state rate was used
ratesAgeDays	Integer	Age of the rate table in days.	When a state rate was used
ratesStale	Boolean	`true` if the table is older than the review period.	When a state rate was used
cart	Object	The cart breakdown.	When `items` was sent
cart.subtotal	Number	Total of all items after any discount.	`items`
cart.taxableSubtotal	Number	Taxable items after any discount.	`items`
cart.exemptSubtotal	Number	Exempt items after any discount.	`items`
cart.shipping	Number	The shipping charge.	`items`
cart.shippingTaxable	Boolean	Whether shipping was taxed.	`items`
cart.taxableAmount	Number	The amount tax was worked out on: taxable items, plus shipping if taxed.	`items`
cart.tax	Number	Tax on the cart.	`items`
cart.total	Number	Total of the cart.	`items`
cart.lines	Array	The cart as readable lines, each with a `label` and a `value`.	`items`
cart.steps	Array	The cart calculation, one step at a time.	`items`
cart.note	String	A note about shipping and the state.	`items`
steps	Array	The calculation, one step at a time.	Always
steps[].label	String	Name of the step, for example `Sales tax`.	Always
steps[].formula	String	The formula used.	Always
steps[].inputs	Object	The numbers that went into the step.	Always
steps[].result	Number	The result of the step.	Always
taxYear	Integer	Tax year of the rates.	Always
sources	String	Where the rates come from, and when they were last checked.	Always
dataStatus	String	Status of the rate data. `estimate` means confirm with the tax authority.	Always
notes	String Array	Notes about this result, such as that local taxes are not included.	Always
disclaimer	String	Use notice.	Always

▣ COMMON ERRORS

Errors any endpoint can return

400bad_request

Required parameter missing or malformed body.

401unauthorized

API key missing, revoked, or not authorized for this service.

429rate_limited

Your plan's per-second rate exceeded. Retry with exponential backoff.

503upstream_busy

Backend temporarily unavailable. Try again in a few seconds.

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