# UK Stamp Duty Land Tax (SDLT) Calculator

> UK Stamp Duty Land Tax (SDLT) Calculator is a paid API for AI agents from property.payapi.market, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Calculates UK Stamp Duty Land Tax owed on a property purchase, applying first-time buyer relief and surcharges for additional properties or non-residents.

## Facts

- Endpoint: POST https://property.payapi.market/stamp-duty
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/property-payapi-market-60143a41
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VzOo2mqkhCQlZlHUcHNgh

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability property-payapi-market-60143a41 -d '<json body>'
```

Example prompt: How much stamp duty will I owe on a £525,000 house in the UK? I'm a first-time buyer and a UK resident, and it's not an additional property.

## When to prefer this

Use this endpoint when you need to compute UK Stamp Duty Land Tax for a property transaction and need to account for first-time buyer relief, additional property surcharges (Oct 2024 rates), or the non-resident 2% surcharge. Prefer this over generic tax calculators when dealing specifically with England/Northern Ireland SDLT rules.

## Known failure modes

- Invalid or negative property price returns validation error
- Missing required 'price' field returns 400 bad request
- Boolean flag type mismatch returns schema validation error
- Server error if upstream computation fails
- Payment not processed (402) if x402 payment header is missing or incorrect

## How this service works

UK Stamp Duty Land Tax (SDLT) calculator with first-time buyer relief and surcharges.

## Output

Returns the calculated UK Stamp Duty Land Tax amount in GBP for the given property price, incorporating first-time buyer relief (for properties up to £625,000), the 5% additional property surcharge (Oct 2024 rates), and the 2% non-resident surcharge where applicable.

## Example request

```json
{
 "price": 525000,
 "is_non_resident": false,
 "is_first_time_buyer": true,
 "is_additional_property": false
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "price": {
   "type": "number",
   "minimum": 0,
   "description": "Property purchase price in GBP."
  },
  "is_non_resident": {
   "type": "boolean",
   "description": "Non-UK residents pay an extra 2% surcharge."
  },
  "is_first_time_buyer": {
   "type": "boolean",
   "description": "First-time buyers get relief on properties up to £625,000."
  },
  "is_additional_property": {
   "type": "boolean",
   "description": "Second homes / buy-to-let pay a 5% surcharge (Oct 2024 rates)."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/property-payapi-market-60143a41/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from property.payapi.market](https://www.zero.xyz/host/property.payapi.market/llms.txt)