# US Payroll & Self-Employment FICA Tax Estimator

> US Payroll & Self-Employment FICA Tax Estimator is a paid API for AI agents from api.agentstools.dev, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Computes US FICA taxes (Social Security, Medicare, and additional Medicare surtax) for either employee wages or self-employment income for a given tax year and filing status.

## Facts

- Endpoint: GET https://api.agentstools.dev/tax/fica
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/us-payroll-self-employment-fica-tax-estimator-64a19009
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_UO6lDC-GRe4cafICZMrcN

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 us-payroll-self-employment-fica-tax-estimator-64a19009
```

Example prompt: What's my total FICA tax bill for 2026 on $135,000 of self-employment net earnings, filing as single?

## When to prefer this

Use this endpoint when you need a fast, pure-computation FICA/payroll tax estimate for a single set of inputs — either for an employee (Social Security + Medicare withholding) or a self-employed person (full SE tax). Prefer it over a generic tax API when you specifically need FICA breakdown including the additional 0.9% Medicare surtax. Not suitable for income tax, capital gains tax, or full tax return computations.

## Known failure modes

- Missing required 'wages' parameter returns a 400 validation error
- Negative wages value rejected with validation error
- Invalid filing_status enum value returns a 422 error
- Unsupported tax year may return an error or fall back to a default
- Non-numeric wages value triggers a type validation failure

## How this service works

US payroll tax estimate: Social Security and Medicare on wages, or self-employment tax, including the additional Medicare surtax. Pure computation over your inputs, not tax advice.

## Output

A breakdown of Social Security tax, Medicare tax, any additional Medicare surtax (0.9% surtax on wages above the threshold), and total FICA or self-employment tax owed, computed from the inputs provided.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "wages"
     ],
     "properties": {
      "wages": {
       "type": "number",
       "description": "Annual wages or net self-employment earnings (>= 0)"
      },
      "tax_year": {
       "type": "integer",
       "description": "Tax year, default 2026"
      },
      "filing_status": {
       "enum": [
        "single",
        "married_jointly",
        "married_separately",
        "head_of_household"
       ],
       "type": "string",
       "description": "Filing status, default single"
      },
      "self_employed": {
       "type": "boolean",
       "description": "True computes self-employment tax, default false"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/us-payroll-self-employment-fica-tax-estimator-64a19009/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.agentstools.dev](https://www.zero.xyz/host/api.agentstools.dev/llms.txt)