Skip to main content
POST
Create a calculation
Quotes tax for a cart at checkout. The response is a Calculation object; use its id to create a transaction once the customer pays.
New in 2026-11-01: every tax_jurisdictions row has a note, and the response has an effective_tax_rate. The request is unchanged from 2026-03-01.

Headers

string
required
Your API key, as Bearer <key>.
string
required
API version. Overrides your account’s default version for this request.

Body

object
required
Who is buying. At least one of customer.address or customer.ip is required.
object
Destination address. Optional when ip is sent; with both, the address is used and the IP is the fallback.
string
string
string
string
ISO 3166-2 subdivision code. Always send it for US addresses.
string
string
ISO 3166-1 alpha-2 country code.
string
shipping or billing. Only valid on customer.address.
object
IP address for location lookup when you don’t have a full address. See IP-based tax resolution.
string
required
A valid IPv4 or IPv6 address.
string
default:"strict"
What to do when the IP can’t be resolved precisely enough: strict (error), zero (zero-rate response), approximate, or best_effort.
string
ID of a customer you created in Numeral. Used for exemptions.
string
default:"CONSUMER"
CONSUMER or BUSINESS.
object[]
Required when type is BUSINESS and the address is outside the US. Not allowed for CONSUMER.
string
required
Tax ID type, e.g. eu_vat, gb_vat, au_abn. See tax IDs.
string
required
The tax ID.
boolean
default:"false"
Skip format and registry checks on tax_ids.
object
required
The cart.
string
required
ISO 4217 currency code. See supported currencies.
boolean
required
Whether line item amounts already include tax. Usually false in North America.
string
required
auto returns real rates where you’re registered. disabled always returns 0. Must be auto for US addresses.
object[]
required
One entry per product. Each needs reference_product_id or product_category.
integer
required
Per-unit price in the currency’s smallest unit. Taxable base is amount × quantity.
integer
required
Quantity sold.
string
Tax category from the category list. Required if no reference_product_id.
string
Your product ID, as created in Numeral. Required if no product_category.
string
Used when reference_product_id isn’t found in Numeral, instead of returning an error.
string
Your line item ID, echoed back for record keeping.
object
Ship-from address. Required unless a default origin is set for the destination on your account.
string
string
string
string
ISO 3166-2 subdivision code.
string
string
ISO 3166-1 alpha-2 country code.
integer
When the sale happened, Unix seconds. Rates and rules are evaluated as of this time. Defaults to now.
string
CONSUMER or BUSINESS. Used when customer.id isn’t found in Numeral, instead of returning an error.
string
CONSUMER. Treat the customer as a consumer when tax ID validation fails, instead of returning a 400.
object
String key-value pairs (values up to 255 characters), echoed back in the response.

Returns

A Calculation object. Errors are listed on the Calculations page.