> For the complete documentation index, see [llms.txt](https://docs.getblock.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.getblock.io/api-reference/bitcoin-btc/btc_estimatesmartfee.md).

# estimatesmartfee - Bitcoin

This method estimates the approximate fee per kilobyte needed for a transaction to begin confirmation within a given number of blocks.

### Parameters

| Parameter      | Type   | Required | Description                                                                                |
| -------------- | ------ | -------- | ------------------------------------------------------------------------------------------ |
| conf\_target   | number | Yes      | Confirmation target in blocks (1 - 1008).                                                  |
| estimate\_mode | string | No       | The fee estimate mode: "unset", "economical", or "conservative" (default: "conservative"). |

### Request

{% tabs %}
{% tab title="cURL" %}

```bash
curl --location --request POST 'https://go.getblock.io/<ACCESS-TOKEN>/' \
--header 'Content-Type: application/json' \
--data-raw '{
    "jsonrpc": "2.0",
    "method": "estimatesmartfee",
    "params": [6, "economical"],
    "id": "getblock.io"
}'
```

{% endtab %}
{% endtabs %}

### Response

```json
{
    "jsonrpc": "2.0",
    "id": "getblock.io",
    "result": {
        "feerate": 0.00012345,
        "blocks": 6
    }
}
```

### Response Parameters

| Field   | Type   | Description                                      |
| ------- | ------ | ------------------------------------------------ |
| feerate | number | Estimate fee rate in BTC/kB (1 kB = 1000 bytes). |
| blocks  | number | Block number where estimate was found.           |
| errors  | array  | Errors encountered during processing (if any).   |

### Use Case

The `estimatesmartfee` method is essential for:

* Dynamic fee calculation for transactions
* Building user fee selection interfaces
* Implementing RBF (Replace-By-Fee) strategies
* Optimizing transaction costs
* Supporting various confirmation time preferences
* Building fee estimation dashboards

### Error Handling

| Status Code | Error Message     | Cause                                |
| ----------- | ----------------- | ------------------------------------ |
| 403         | Forbidden         | Missing or invalid ACCESS-TOKEN.     |
| -1          | Insufficient data | Not enough data to make an estimate. |

### Integration Notes

The `estimatesmartfee` method helps developers:

* Build dynamic fee calculators
* Implement priority-based fee selection
* Create cost-optimized transaction systems
* Support time-sensitive transactions
* Build fee comparison tools


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.getblock.io/api-reference/bitcoin-btc/btc_estimatesmartfee.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.