Spanish VAT (IVA) Calculator With IRPF and Equivalence Surcharge

contix/calculate-iva

Calculates Spanish VAT (IVA) on an amount with the rate you choose: the taxable base, the VAT quota, the equivalence surcharge and its amount, the IRPF withholding and its amount, the total with VAT and the invoice total. Set incluye_iva to true when the amount already includes VAT and the base must be extracted. This is arithmetic with the rates you give; it does not decide which rate applies. Data from the Contix public tools API, served by Eden Engine; not an official Contix product.

activeper callv1

Price

$0.0026 per call

You pay the price shown. If a call turns out to cost more than its quote, you pay the actual price, capped at twice the quote. No monthly minimum. Top-ups start at $0.50.

Data source

Contix

Data from the Contix public tools API (https://api.contix.es). Served by Eden Engine; not an official Contix product.

Use it

Five steps: search, inspect, learn, run, settle. No per-tool setup; your agent reaches this tool through the meta-tools it already has.

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agent

// 1. search: find the tool
omnial_search({ query: "what you need" })

// 2. inspect: price and input schema
omnial_inspect({ tool: "contix/calculate-iva" })

// 3. learn: read the usage guide at runtime
omnial_learn({ tool: "contix/calculate-iva" })

// 4. run: price the exact call first, then run it
omnial_execute({ tool: "contix/calculate-iva", input: { /* see input_schema */ }, dry_run: true })
omnial_execute({ tool: "contix/calculate-iva", input: { /* ... */ } })

// 5. settle: the call is charged when it finishes, nothing to do

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Pricing

Every charge this tool can incur.

Charge	Price
Per call	$0.0026

Updated: Oct 25, 2026

Input and output schemas

Input schema

input_schema.json

{
  "type": "object",
  "required": [
    "importe",
    "tipo_iva"
  ],
  "properties": {
    "irpf": {
      "type": "number",
      "maximum": 100,
      "minimum": 0,
      "description": "IRPF withholding rate in percent; omit for none."
    },
    "importe": {
      "type": "number",
      "maximum": 1000000000,
      "minimum": 0,
      "description": "The amount: the taxable base, or the gross amount when incluye_iva is true."
    },
    "recargo": {
      "type": "number",
      "maximum": 100,
      "minimum": 0,
      "description": "Equivalence surcharge rate in percent; omit for none."
    },
    "tipo_iva": {
      "type": "number",
      "maximum": 100,
      "minimum": 0,
      "description": "VAT rate in percent, for example 21, 10, 4 or 0."
    },
    "incluye_iva": {
      "type": "boolean",
      "description": "True when importe already includes VAT."
    }
  },
  "additionalProperties": false
}

Output schema

output_schema.json

{
  "type": "object",
  "required": [
    "base_imponible",
    "tipo_iva",
    "cuota_iva",
    "total_factura"
  ],
  "properties": {
    "irpf": {
      "type": "string",
      "description": "IRPF rate, percent."
    },
    "aviso": {
      "type": "string",
      "description": "The publisher's notice that the result is arithmetic or registry output, not advice."
    },
    "tipo_iva": {
      "type": "string",
      "description": "VAT rate used, percent."
    },
    "cuota_iva": {
      "type": "string",
      "description": "VAT quota."
    },
    "total_con_iva": {
      "type": "string",
      "description": "Base plus VAT (and surcharge)."
    },
    "total_factura": {
      "type": "string",
      "description": "Invoice total after withholding."
    },
    "base_imponible": {
      "type": "string",
      "description": "Taxable base."
    },
    "retencion_irpf": {
      "type": "string",
      "description": "IRPF withholding amount."
    },
    "recargo_importe": {
      "type": "string",
      "description": "Equivalence surcharge amount."
    },
    "recargo_equivalencia": {
      "type": "string",
      "description": "Equivalence surcharge rate, percent."
    }
  },
  "description": "The VAT breakdown. Amounts are decimal strings in euros.",
  "additionalProperties": true
}