🚗 Finnish Car Tax API

Calculate Finnish car tax (autovero) for any European vehicle — powered by auto-saksasta.fi

Base URL

POST https://auto-saksasta.fi/partner_api.php

Authentication

Include your API key as a Bearer token in the Authorization header:

"Authorization": "Bearer YOUR_API_KEY"

Your API Key (kenneth@parrotz.fi)

parrotz2026xKenneth40chars1234567890ab

Keep this secret. Monthly quota: 500 requests. Contact tomi@auto-saksasta.fi to increase.

📥 Request

Send a JSON body with the vehicle details. All AutoScout24 fields map directly.

Field	Type	Required	Description
make	string	required	Brand, e.g. "BMW", "Volkswagen"
model	string	required	Model + variant, e.g. "330d Touring", "Golf GTI"
year	int	required	Registration year, e.g. 2021
mileage	int	required	Odometer in km, e.g. 55000
fuel	string	required	diesel · petrol · electric · hybrid · phev
co2	int	required	CO₂ emissions g/km. The tax rate is calculated directly from this value — missing CO₂ makes accurate calculation impossible. Electric vehicles: send 0.
co2_standard	string	required	WLTP or NEDC. Rule: 2020+ → WLTP, 2019 and older → NEDC. Wrong standard causes incorrect tax rate.
first_registration	string	important	Exact date YYYY-MM-DD — critical for under-12-month vehicles (determines which depreciation formula applies). Also required for correct WLTP/NEDC table selection.
body_type	string	optional	Sedan · Estate · Coupe · Cabriolet · SUV · Hatchback
power_kw	int	optional	Engine power in kW
engine_cc	int	optional	Engine displacement in cc
price_eur	float	optional	EU asking price (€). Used as fallback verotusarvo base when no tax decisions found. See accuracy warnings below.
finnish_list_price	float	optional	Finnish new-car list price incl. all factory options (€). Strongly recommended for vehicles under 24 months old — produces significantly more accurate results than EU price.

💡 Tip: Always send co2 + co2_standard when available — the tax rate is calculated directly from CO₂ emissions and can vary significantly (e.g. 3% vs 25% for same model year).

Example Request

POST https://auto-saksasta.fi/partner_api.php
Authorization: Bearer parrotz2026xKenneth40chars1234567890ab
Content-Type: application/json

{
  "make":         "BMW",
  "model":        "330d Touring",
  "year":         2021,
  "mileage":      55000,
  "fuel":         "diesel",
  "co2":          142,
  "co2_standard": "WLTP",
  "body_type":    "Estate",
  "power_kw":     140,
  "price_eur":    32000
}

📤 Response

Field	Type	Description
ok	bool	true = success
verotusarvo_eur	int	Taxable value in € (assessed by Finnish tax authority)
veroprosentti	float	Tax rate % (based on CO₂ emissions)
autovero_eur	int	Car tax in € = verotusarvo × veroprosentti
kokonaishinta_fi_eur	int	Estimated total Finland price = price_eur + autovero (only if price_eur sent)
selitys	string	AI reasoning in Finnish — explains the estimate and comparable decisions used
ai_perusteet	array	Comparable tax decisions used (see below)
meta.no_match	bool	true = no comparable decisions found, price-based fallback used
meta.price_based	bool	true = verotusarvo derived from price_eur (formula below)
meta.decision_count	int	Number of comparable tax decisions found in database
meta.monthly_used	int	Requests used this month

ai_perusteet (comparable decisions)

Field	Description
malli	Model variant key
ika_kk	Age in months at time of tax decision
km	Mileage at time of decision
verotusarvo	Taxable value decided (€)
veroprosentti	Tax rate applied (%)
autovero	Car tax paid (€)
sama_prosentti	true = same tax rate as calculated for this vehicle

Example Response

{
  "ok":                   true,
  "verotusarvo_eur":     29500,
  "veroprosentti":       14.5,
  "autovero_eur":        4278,
  "kokonaishinta_fi_eur":36278,
  "selitys": "BMW 330d Touring (2021, diesel, WLTP 142 g/km)... SUOSITELTU ARVO: 29500 €",
  "ai_perusteet": [
    {
      "malli":          "330 TOURING CDI",
      "ika_kk":         36,
      "km":             52000,
      "verotusarvo":    28800,
      "veroprosentti":  14.5,
      "autovero":       4176,
      "sama_prosentti": true
    }
  ],
  "meta": {
    "make":           "BMW",
    "model_base":     "330",
    "age_months":     50,
    "fuel_norm":      "diesel",
    "decision_count": 8,
    "no_match":       false,
    "price_based":    false,
    "monthly_used":   1,
    "monthly_limit":  500
  }
}

🔢 Tax Calculation Logic

Tax Rate (veroprosentti)

Determined by CO₂ emissions using official Finnish tables (WLTP 2020+, NEDC for older cars). Electric vehicles: 0% (registered after Oct 2021).

Examples: 0 g/km = 0% · 100 g/km ≈ 7% · 142 g/km ≈ 14.5% · 200 g/km ≈ 29.7% · 250 g/km ≈ 38.6%

Taxable Value (verotusarvo)

Determined by AI analysis of the Finnish Tax Authority's (Verohallinto) actual past decisions for comparable vehicles. The database contains tens of thousands of real tax decisions.

Price-based Fallback (meta.price_based = true)

When no comparable decisions are found and price_eur is provided, the taxable value is derived from the EU asking price:

// Formula: EU price = verotusarvo × (1 − tax_rate/100)
verotusarvo = price_eur / (1 − veroprosentti/100)
autovero    = verotusarvo × veroprosentti/100

// Example: BMW M5 (rare), price 80 000 €, tax rate 20%
verotusarvo = 80000 / (1 − 0.20) = 100 000 €
autovero    = 100000 × 0.20      = 20 000 €

This fallback applies to rare or unusual vehicles (Rolls-Royce, AMG specials, etc.) where the tax database has no comparable decisions.

⚠️ Under-1-Year Vehicles (age_months < 12)

IMPORTANT: Finnish tax authority (Verohallinto) always uses the Finnish new-car list price (uushankintahinta) — including all factory options — as the calculation base for vehicles under 12 months old. Past tax decisions from the database are NOT used.

The calculation for vehicles under 12 months old follows the official Verohallinto formula:

// Step 1: Apply 3% cash discount
base = finnish_list_price × 0.97

// Step 2: Monthly depreciation
base = base × (1 − 0.02) ^ min(age_months, 2)     // −2%/month, first 2 months
base = base × (1 − 0.01) ^ max(0, age_months − 2)  // −1%/month, remaining months

verotusarvo = base
autovero    = verotusarvo × veroprosentti/100

Accuracy Warning — When to provide `finnish_list_price`

Scenario	Risk	Recommendation
Age 0–12 months	HIGH — EU market price may have dropped 20–30%, while Verohallinto only deducts ~10.5%	Always provide `finnish_list_price` with full factory options
Age 12–24 months, rare/uncommon model	MEDIUM–HIGH — No real Finnish used-car price data exists for rare models; AI estimate may deviate significantly	Calculate from `finnish_list_price` with depreciation; do not rely on AI decision data
Age >24 months, common model	LOW — Sufficient real Finnish tax decisions available	AI estimate from tax decisions is reliable

EU price fallback limitation: Using the EU asking price as a substitute for the Finnish list price typically produces an underestimate for lightly-used vehicles (0–18 months). During the first 6 months, a premium vehicle may lose 20–30% of its value on the European market (depreciation, negotiation) — while Verohallinto deducts only ~10.5% from the Finnish list price. This means EU price ≈ Finnish taxable value, but it should actually be higher. Always use the official Finnish price list (hinnasto) with all factory-fitted options for accurate results.

⚠️ Error Responses

HTTP	Error	Cause
401	Invalid or missing API key	Wrong or missing Bearer token
400	make ja model vaaditaan	Required fields missing
429	Monthly quota exceeded	500 req/month limit reached
502	Engine error	Internal calculation error — retry

🛠 Integration Tips

⏱ Latency: Expect 3–8 seconds response time — the AI analysis step takes time. Use async/non-blocking calls.

🔁 Batch processing: When importing an AS24 listing batch, queue requests with a small delay (1–2s) to stay within rate limits.

Fuel Type Mapping from AutoScout24

AS24 value	Send as
Petrol / Benzin	petrol
Diesel	diesel
Electric / Elektro	electric
Hybrid (mild/full)	hybrid
Plug-in Hybrid	phev
CNG / LPG / Ethanol	petrol

Body Type Mapping from AutoScout24

AS24 value	Send as
Limousine / Sedan	Sedan
Kombi / Estate / Touring	Estate
Coupe / Coupé	Coupe
Cabriolet / Roadster / Convertible	Cabriolet
SUV / Geländewagen	SUV
Kleinwagen / Hatchback	Hatchback

Finnish Car Tax API · auto-saksasta.fi · Questions: tomi@auto-saksasta.fi

🚗 Finnish Car Tax API

Base URL

Authentication

Your API Key (kenneth@parrotz.fi)

📥 Request

Example Request

📤 Response

ai_perusteet (comparable decisions)

Example Response

🔢 Tax Calculation Logic

Tax Rate (veroprosentti)

Taxable Value (verotusarvo)

Price-based Fallback (meta.price_based = true)

⚠️ Under-1-Year Vehicles (age_months < 12)

Accuracy Warning — When to provide finnish_list_price

⚠️ Error Responses

🛠 Integration Tips

Fuel Type Mapping from AutoScout24

Body Type Mapping from AutoScout24

Accuracy Warning — When to provide `finnish_list_price`