> ## Documentation Index
> Fetch the complete documentation index at: https://docs.taxmaxi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Calculate tax for a source — TaxMaxi Sources API

> Run a jurisdiction-aware tax calculation on a synced source to get taxable gains, losses, tax-free gains, and total income for a given year.

Once a source has a completed sync, you can calculate its tax liability for any year and jurisdiction. TaxMaxi applies FIFO (first-in, first-out) accounting to your normalized transaction records and returns a breakdown of gains, losses, and income. The calculation runs on demand each time you call the endpoint, so you can re-run it after a replay or for different years without any additional setup.

**Required header:** `Authorization: Bearer <token>`

<Note>
  TaxMaxi provides tax calculation results for informational purposes only. The output of this API is not tax advice. You should consult a qualified tax professional before filing any tax return.
</Note>

## Calculate tax

Calculates jurisdiction-specific tax figures from normalized FIFO and income data for the specified source.

```
POST /v1/sources/:sourceId/tax
```

The source must have a sync with `status: "completed"` before you call this endpoint. If the source has never been synced or the most recent sync failed, the API returns a `404`.

### Path parameters

<ParamField path="sourceId" type="string" required>
  The ID of the source to calculate tax for.
</ParamField>

### Request body

<ParamField body="year" type="integer" required>
  The tax year to calculate. Must be between `1970` and the current year (inclusive).
</ParamField>

<ParamField body="jurisdiction" type="string" required>
  The tax jurisdiction to apply. Currently supported: `"germany"`.
</ParamField>

### Response fields

<ResponseField name="year" type="number" required>
  The tax year the calculation applies to.
</ResponseField>

<ResponseField name="currency" type="string" required>
  The base currency in which all monetary values are expressed (e.g. `"EUR"`).
</ResponseField>

<ResponseField name="taxableGains" type="number" required>
  Net gains from crypto assets held for less than one year. These are subject to income tax in Germany.
</ResponseField>

<ResponseField name="taxableLosses" type="number" required>
  Net losses from crypto assets held for less than one year. These can offset taxable gains.
</ResponseField>

<ResponseField name="taxFreeGains" type="number" required>
  Gains from crypto assets held for more than one year. Under German tax law, these gains are tax-free.
</ResponseField>

<ResponseField name="incomeTotal" type="number" required>
  Total income from non-trade events such as staking rewards, airdrops, and other income-classified transactions.
</ResponseField>

### Errors

| Status | Code                    | Description                                                                   |
| ------ | ----------------------- | ----------------------------------------------------------------------------- |
| `400`  | `SourceBadRequestError` | The request body is missing required fields or contains invalid values.       |
| `404`  | `SourceNotFoundError`   | No source was found for the given ID, or the source has not completed a sync. |
| `500`  | `InternalServerError`   | An unexpected server error occurred.                                          |

### Example

<CodeGroup>
  ```bash cURL theme={null}
  curl --request POST \
    https://api.taxmaxi.com/v1/sources/src_01hzqe3kj8t2v5n6b7d9f0gx/tax \
    --header "Authorization: Bearer <token>" \
    --header "Content-Type: application/json" \
    --data '{
      "year": 2024,
      "jurisdiction": "germany"
    }'
  ```
</CodeGroup>

```json Response theme={null}
{
  "year": 2024,
  "currency": "EUR",
  "taxableGains": 4250.80,
  "taxableLosses": 310.50,
  "taxFreeGains": 12000.00,
  "incomeTotal": 875.25
}
```

## Understanding the response

| Field           | Description                                                                                                |
| --------------- | ---------------------------------------------------------------------------------------------------------- |
| `taxableGains`  | Gains from selling or swapping crypto held for less than 12 months. In Germany, these are taxed as income. |
| `taxableLosses` | Losses from assets held less than 12 months. You can offset these against taxable gains in the same year.  |
| `taxFreeGains`  | Gains from assets held for more than 12 months. German tax law exempts these from taxation.                |
| `incomeTotal`   | The total value received from staking rewards, airdrops, and similar income events at the time of receipt. |

All values are in the base currency returned in the `currency` field.