GST Calculation API

Calculate inclusive or exclusive GST and return CGST/SGST or IGST splits for an application workflow. Host https://mantechstudio.in/api/v1with Authorization: Bearer and a console TEST key.

Try in Playground Use the GST calculator

Available in TEST·Live in TEST on https://mantechstudio.in/api/v1 using Developer Console keys (Authorization: Bearer mantech_test_…). /external/v1 is a different credential store.

This API does not file GST returns, connect to GSTN, generate e-invoices, determine every legal place-of-supply scenario, or apply exemptions that are not represented in the inputs. Results are not tax advice.

POST/api/v1/gst/calculate

Required JSON fields: amount, taxRate. Optional: pricingMode (default exclusive), supplyType (default intra_state), sellerStateCode, buyerStateCode (both together if used). Unknown fields are rejected. Request body limit is 32 KiB. Content-Type must be application/json.

amount — rupees, number or decimal string, max 10,000,000,000, max 2 decimal places. Outputs are 2-decimal strings.
taxRate — percent. 18 means 18%, not 0.18. Range 0–100.
exclusive: amount is taxable value. inclusive: amount is gross including GST.
intra_state → CGST + SGST. inter_state → IGST. State-code equality is not full POS law.
Results are rounded to paise. Intra-state leftover paise is assigned to CGST.
Cache-Control: private, no-store. GET is not supported.

cURL

curl -X POST "https://mantechstudio.in/api/v1/gst/calculate" \
  -H "Authorization: Bearer mantech_test_0123456789abcdef.example_secret" \
  -H "Content-Type: application/json" \
  -d '{"amount":"1000.00","taxRate":18,"pricingMode":"exclusive","supplyType":"intra_state"}'

JavaScript fetch

const res = await fetch('https://mantechstudio.in/api/v1/gst/calculate', {
  method: 'POST',
  headers: {
    Authorization: 'Bearer mantech_test_0123456789abcdef.example_secret',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
  "amount": "1000.00",
  "taxRate": 18,
  "pricingMode": "exclusive",
  "supplyType": "intra_state"
})
});
const data = await res.json();

Example 200 body

{
  "currency": "INR",
  "pricingMode": "exclusive",
  "supplyType": "intra_state",
  "determinationMethod": "explicit",
  "taxRate": 18,
  "inputAmount": "1000.00",
  "taxableAmount": "1000.00",
  "cgst": "90.00",
  "sgst": "90.00",
  "igst": "0.00",
  "totalTax": "180.00",
  "totalAmount": "1180.00"
}

Compatibility aliases (not preferred): gst_rate, calculation_type, supply_type, supplier_state_code, place_of_supply_state_code.

Playground · Auth, errors, quota

Loading…

curl -X POST "https://mantechstudio.in/api/v1/gst/calculate" \ -H "Authorization: Bearer mantech_test_0123456789abcdef.example_secret" \ -H "Content-Type: application/json" \ -d '{"amount":"1000.00","taxRate":18,"pricingMode":"exclusive","supplyType":"intra_state"}'

const res = await fetch('https://mantechstudio.in/api/v1/gst/calculate', { method: 'POST', headers: { Authorization: 'Bearer mantech_test_0123456789abcdef.example_secret', 'Content-Type': 'application/json' }, body: JSON.stringify({ "amount": "1000.00", "taxRate": 18, "pricingMode": "exclusive", "supplyType": "intra_state" }) }); const data = await res.json();

{ "currency": "INR", "pricingMode": "exclusive", "supplyType": "intra_state", "determinationMethod": "explicit", "taxRate": 18, "inputAmount": "1000.00", "taxableAmount": "1000.00", "cgst": "90.00", "sgst": "90.00", "igst": "0.00", "totalTax": "180.00", "totalAmount": "1180.00" }