{
  "id": "bas",
  "version": "e42ba6d46f3d",
  "status": "published",
  "name": "BAS Calculator",
  "question": "How much do I owe on my BAS?",
  "summary": "Works out the GST on sales (1A), GST credits on purchases (1B), PAYG withholding and PAYG instalment for an Australian business activity statement, and the net amount to pay or get back.",
  "category": "finance",
  "subcategory": "tax-and-pay",
  "url": "https://www.acalculator.org/finance/bas-calculator",
  "markdown": "https://www.acalculator.org/finance/bas-calculator.md",
  "kind": "function",
  "method": "1A = (G1 − GST-free sales) ÷ 11; 1B = (purchases − purchases with no GST) ÷ 11; T11 = T1 × T2 ÷ 100; net = 1A − 1B + W2 + T11. A negative net is a refund.",
  "assumptions": [
    "GST is 10%, so the GST in a GST-inclusive amount is one eleventh of it (ATO).",
    "Sales and purchases are typed including GST, as on the BAS labels G1, G10 and G11.",
    "The page does not apply adjustments (1G, 7), fuel tax credits, wine equalisation tax, luxury car tax, or a PAYG instalment varied from the ATO amount. It is an estimate, not tax advice."
  ],
  "inputs": {
    "$schema": "https://json-schema.org/draft/2020-12/schema",
    "type": "object",
    "properties": {
      "g1": {
        "title": "Total sales (G1)",
        "description": "All sales in the period, including GST, as on label G1.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "g3": {
        "title": "GST-free sales and exports (G2 + G3)",
        "description": "Export sales (G2) and other GST-free sales (G3) included in G1; no GST is due on them.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "g11": {
        "title": "Purchases (G10 + G11)",
        "description": "Capital purchases (G10) and other purchases (G11), including GST.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "nogst": {
        "title": "Purchases with no GST in them",
        "description": "The part of the purchases that had no GST: GST-free or input-taxed items, wages, and private use.",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "w2": {
        "title": "PAYG tax withheld (W2)",
        "description": "Tax withheld from wages and other payments in the period (label W2).",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "t1": {
        "title": "PAYG instalment income (T1)",
        "description": "Instalment income for the quarter, if you pay PAYG instalments by rate (label T1).",
        "type": "number",
        "x-unit": "USD",
        "minimum": 0,
        "maximum": 1000000000000
      },
      "t2": {
        "title": "PAYG instalment rate (T2)",
        "description": "The instalment rate the ATO gave you (label T2).",
        "type": "number",
        "x-unit": "percent",
        "minimum": 0,
        "maximum": 100
      }
    }
  },
  "outputs": {
    "net": {
      "label": "Net amount",
      "description": "GST on sales plus PAYG withheld and instalment, less GST credits. Negative means a refund.",
      "format": "money"
    },
    "direction": {
      "label": "Pay or refund",
      "description": "Whether you pay the ATO or the ATO pays you.",
      "format": "text"
    },
    "gstOnSales": {
      "label": "GST on sales (1A)",
      "description": "One eleventh of the taxable sales.",
      "format": "money"
    },
    "gstCredits": {
      "label": "GST credits (1B)",
      "description": "One eleventh of purchases that included GST.",
      "format": "money"
    },
    "netGst": {
      "label": "Net GST",
      "description": "1A less 1B. Negative means a GST refund.",
      "format": "money"
    },
    "instalment": {
      "label": "PAYG instalment (T11)",
      "description": "Instalment income times the instalment rate.",
      "format": "money"
    },
    "withheldOut": {
      "label": "PAYG withheld (W2)",
      "description": "The tax withheld, as typed.",
      "format": "money"
    }
  },
  "defaultAnswer": {
    "inputs": {
      "g1": 55000,
      "g3": 0,
      "g11": 22000,
      "nogst": 0,
      "w2": 0,
      "t1": 0,
      "t2": 0
    },
    "outputs": {
      "net": 3000,
      "direction": "You pay the ATO",
      "gstOnSales": 5000,
      "gstCredits": 2000,
      "netGst": 3000,
      "instalment": 0,
      "withheldOut": 0
    },
    "text": "Net amount for this BAS: $3,000.00. You pay the ATO."
  },
  "examples": [
    {
      "given": {
        "g1": 55000,
        "g11": 22000
      },
      "expect": {
        "gstOnSales": 5000,
        "gstCredits": 2000,
        "netGst": 3000,
        "net": 3000,
        "direction": "You pay the ATO"
      },
      "source": "ATO, Quarterly GST reporting, https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst/when-and-how-to-report-and-pay-gst/quarterly-gst-reporting; hand calculation in content.mdx: 1A = 55,000 ÷ 11, 1B = 22,000 ÷ 11; Python 3: 55000/11 - 22000/11"
    },
    {
      "given": {
        "g1": 33000,
        "g3": 5500,
        "g11": 13200,
        "nogst": 2200,
        "w2": 4100,
        "t1": 30000,
        "t2": 4.5
      },
      "expect": {
        "gstOnSales": 2500,
        "gstCredits": 1000,
        "netGst": 1500,
        "instalment": 1350,
        "net": 6950
      },
      "source": "ATO, Quarterly GST reporting, https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst/when-and-how-to-report-and-pay-gst/quarterly-gst-reporting; hand calculation in content.mdx: (33,000 − 5,500) ÷ 11 = 2,500; (13,200 − 2,200) ÷ 11 = 1,000; 30,000 × 4.5% = 1,350; 1,500 + 4,100 + 1,350"
    },
    {
      "given": {
        "g1": 11000,
        "g11": 66000
      },
      "expect": {
        "netGst": -5000,
        "net": -5000,
        "direction": "The ATO refunds you"
      },
      "source": "ATO, Quarterly GST reporting, https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst/when-and-how-to-report-and-pay-gst/quarterly-gst-reporting; hand calculation in content.mdx: a quarter with a large purchase; 1,000 − 6,000"
    },
    {
      "given": {
        "g1": 100
      },
      "expect": {
        "gstOnSales": 9.090909090909092,
        "net": 9.090909090909092
      },
      "source": "ATO, Quarterly GST reporting, https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst/when-and-how-to-report-and-pay-gst/quarterly-gst-reporting; hand calculation in content.mdx: GST is one eleventh of a GST-inclusive price; Python 3: 100/11"
    }
  ],
  "sources": [
    "ATO, How Australian GST works: the rate is 10% and GST is one eleventh of the price (updated 11 September 2025, retrieved 2026-10-05). https://www.ato.gov.au/businesses-and-organisations/international-tax-for-business/gst-for-non-resident-businesses/how-australian-gst-works",
    "ATO, Quarterly GST reporting: labels G1, G2, G3, G10, G11, 1A and 1B, and Simpler BAS (retrieved 2026-10-05). https://www.ato.gov.au/businesses-and-organisations/gst-excise-and-indirect-taxes/gst/when-and-how-to-report-and-pay-gst/quarterly-gst-reporting",
    "ATO, PAYG withholding on the BAS: labels W1 and W2 (retrieved 2026-10-05). https://www.ato.gov.au/businesses-and-organisations/preparing-lodging-and-paying/business-activity-statements-bas/pay-as-you-go-payg-withholding",
    "ATO, PAYG instalments: how to complete your activity statement, labels T1, T2 and 5A (retrieved 2026-10-05). https://www.ato.gov.au/forms-and-instructions/payg-instalments-how-to-complete-your-activity-statement"
  ],
  "related": [
    "sales-tax",
    "reverse-sales-tax",
    "payroll-tax"
  ],
  "changelog": []
}