Calculators

Add or remove NZ GST

Add or remove NZ GST (15%) from an amount.

mode decides which way round the amount is read. "add" treats it as GST-exclusive and works out the GST on top; "remove" treats it as GST-inclusive and works out how much of it is GST. Getting this backwards is the usual source of a wrong answer: removing GST from $115 gives $100, while taking 15% off $115 gives $97.75, which is not the same thing.

Every response returns all three figures regardless of mode, so the one you need is always present.

gst_rate is overridable for historical work: GST was 12.5% before 1 October 2010. It has been 15% since.

post/v1/gst

Request

Base URL: https://api.calculate.co.nz
URL: https://api.calculate.co.nz/v1/gst
Auth: API key in header X-API-Key

Request body

amountnumber required

Dollar amount in NZD

mode'add' | 'remove'

'add' treats amount as GST-exclusive; 'remove' as GST-inclusive.

gst_ratenumber

GST rate as a decimal. NZ standard 0.15 (15%).

Example request

{
  "amount": 100,
  "gst_rate": 0.15,
  "mode": "add"
}

Response

The amount split into its GST-exclusive, GST and GST-inclusive parts.

disclaimerstring required

Scope and limits of this calculation.

Example response

{
  "disclaimer": "Calculation based on standard NZ GST rate. Not tax advice.",
  "result": {
    "amount_excl_gst": 100,
    "amount_incl_gst": 115,
    "gst_content": 15,
    "gst_rate": 0.15,
    "input_amount": 100,
    "mode": "add"
  }
}

Changes

No recorded changes to this operation across all 1 revision of this API.