# Estimate a New Zealand GST return

Estimate the boxes of a GST return for a full period from your sales and purchase totals, on an invoice, payments or hybrid basis, with anything assumed nil listed.

Canonical: https://aroai.com/tools/nz_gst_return_estimate/

## Tool reference

MCP tool ID: `nz_gst_return_estimate`. Availability: Live. Country: New Zealand.

Credit use: 1 credit.

## Input schema

```json
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "period_start": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "period_end": {
      "type": "string",
      "pattern": "^\\d{4}-\\d{2}-\\d{2}$"
    },
    "filing_frequency": {
      "type": "string",
      "enum": [
        "monthly",
        "two_monthly",
        "six_monthly"
      ]
    },
    "accounting_basis": {
      "type": "string",
      "enum": [
        "invoice",
        "payments",
        "hybrid"
      ]
    },
    "sales": {
      "type": "object",
      "properties": {
        "standard_rated_inclusive": {
          "type": "number",
          "minimum": 0,
          "maximum": 100000000,
          "description": "GST-inclusive standard-rated sales for accounting_basis: invoice and hybrid = supplies first attributed to this period by invoice or any earlier payment (whichever comes first, subject to special rules); payments = received. Enter zero-rated and exempt sales separately."
        },
        "zero_rated": {
          "description": "GST-inclusive zero-rated sales under the selected basis.",
          "type": "number",
          "minimum": 0,
          "maximum": 100000000
        },
        "exempt": {
          "description": "Exempt sales under the selected basis; excluded from Box 5.",
          "type": "number",
          "minimum": 0,
          "maximum": 100000000
        }
      },
      "required": [
        "standard_rated_inclusive"
      ],
      "additionalProperties": false
    },
    "purchases": {
      "type": "object",
      "properties": {
        "standard_rated_inclusive": {
          "type": "number",
          "minimum": 0,
          "maximum": 100000000,
          "description": "GST-inclusive standard-rated purchases for accounting_basis: invoice = purchases first attributed to this period by invoice or any earlier payment (with a valid taxable supply record); payments/hybrid = paid. Exclude imports; enter Customs GST separately."
        }
      },
      "required": [
        "standard_rated_inclusive"
      ],
      "additionalProperties": false
    },
    "adjustments": {
      "default": {},
      "type": "object",
      "properties": {
        "private_use_gst": {
          "description": "Calculated private-use GST debit adjustment for this period.",
          "type": "number",
          "minimum": 0,
          "maximum": 100000000
        },
        "other_debit_gst": {
          "description": "Calculated other GST debit adjustments for this period.",
          "type": "number",
          "minimum": 0,
          "maximum": 100000000
        },
        "customs_gst_paid": {
          "description": "Customs GST paid on imports, as calculated from Customs records.",
          "type": "number",
          "minimum": 0,
          "maximum": 100000000
        },
        "other_credit_gst": {
          "description": "Calculated other GST credit adjustments for this period.",
          "type": "number",
          "minimum": 0,
          "maximum": 100000000
        }
      },
      "additionalProperties": false
    }
  },
  "required": [
    "period_start",
    "period_end",
    "filing_frequency",
    "accounting_basis",
    "sales",
    "purchases",
    "adjustments"
  ],
  "additionalProperties": false
}
```

## Example input

```json
{
  "period_start": "2026-09-01",
  "period_end": "2026-10-31",
  "filing_frequency": "two_monthly",
  "accounting_basis": "invoice",
  "sales": {
    "standard_rated_inclusive": 69000
  },
  "purchases": {
    "standard_rated_inclusive": 23000
  },
  "adjustments": {}
}
```

## Usage notes

- Totals are GST-inclusive standard-rated amounts.
- Omitted zero-rated sales or adjustments are listed and can mark the estimate incomplete.
- Mixed-use assets and land transactions are left for review.