# Normalized ATR and ATR Percentage

`D07-F06-A01` · Technical Indicators → Range and Volatility Indicators · archetype `series-transform` · difficulty 2/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/range-and-volatility-indicators/normalized-atr-and-atr-percentage/
Agent skill: `npx skills add IslamBaraka90/Fintech-Algorithms-Library` — https://docs.thefintechbuilder.com/guides/agent-skill/

## Install and import

```bash
npm install fintech-algorithms
```

```ts
import { normalizedAtrAndAtrPercentage } from "fintech-algorithms/technical-indicators/range-and-volatility-indicators/normalized-atr-and-atr-percentage";
```

## Signature

```ts
normalizedAtrAndAtrPercentage(input)
```

Wilder's Average True Range over `period` bars, and the same figure restated as a percentage of that bar's close.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | `TopicInput` | yes | `bars` is the required OHLCV array -- each bar carries `timestamp`, `open`, `high`, `low`, `close`, `volume` and an optional `basis`, strictly ordered by timestamp. From `parameters` this topic reads only `period` (default 14, integer >= 2), which is the Wilder RMA length used for the ATR. |

## Returns

`TopicResult`

`series` holds `atr`, the Wilder RMA of true range, and `natr`, `100 * atr / close`. `latest` carries the last value of each. Both share the same warm-up: `period - 1` leading nulls, so `ready_at` is 13 at the default period, the index where the RMA seed completes.

## Warm-up

The first ``period - 1` bars (13 at the default period)` positions are `null`. The ATR is seeded by averaging the first `period` true ranges, so nothing is emitted until that many bars exist. `natr` is derived from `atr` and inherits the same prefix; it is also null on any bar whose close is zero.

## Errors

- When `parameters.period` is not an integer >= 2 — throws Error
- When a bar is missing open, high, low, close, or volume, or one of them is not a finite number — throws Error
- When bars are not strictly ordered by timestamp, or a bar's high is below its open, low, or close — throws Error

## Complexity

Time `O(n)`, space `O(n)`.

## Worked example

Captured by running this function on the input its own test provides. Real output of real code — but not asserted against a published figure.

### Input

`input`:

```json
{
  "bars": [
    {
      "timestamp": "2024-01-02",
      "basis": "synthetic-unadjusted",
      "open": 100,
      "high": 101.45,
      "low": 98.695,
      "close": 100,
      "volume": 750000,
      "benchmark": 200
    },
    {
      "timestamp": "2024-01-03",
      "basis": "synthetic-unadjusted",
      "open": 101.49111452,
      "high": 103.38381693,
      "low": 100.05480022,
      "close": 101.78791214,
      "volume": 795117,
      "benchmark": 200.56326135
    },
    {
      "timestamp": "2024-01-04",
      "basis": "synthetic-unadjusted",
      "open": 102.45519048,
      "high": 104.6701838,
      "low": 100.91147007,
      "close": 102.9549389,
      "volume": 840234,
      "benchmark": 201.11020913
    }
  ],
  "parameters": {}
}
```

### Call

```ts
normalizedAtrAndAtrPercentage(input)
```

### Returns

object with 9 fields: topic_id, title, state, ready, ready_at, series, latest, parameters, …

```json
{
  "topic_id": "D07-F06-A01",
  "title": "Normalized ATR and ATR Percentage",
  "state": "calculated",
  "ready": true,
  "ready_at": 13,
  "series": {
    "atr": [null, null, null, null, null, null],
    "natr": [null, null, null, null, null, null]
  },
  "latest": {
    "atr": 3.245219101666433,
    "natr": 3.2455172196242965
  },
  "parameters": {},
  "diagnostics": {
    "causal": true,
    "input_count": 96
  }
}
```

## Verification and provenance

Tier: **verified** (via E).

The worked example below is the figure published in this algorithm's article, replayed and asserted by the test suite on every build. The arithmetic cannot drift without the build failing.

Both tiers guarantee the signature. Full explanation: https://docs.thefintechbuilder.com/guides/verification/

Generated from the docs.json payload shipped inside fintech-algorithms@0.13.0.
The signature and parameter list are checked against the compiled implementation at build time,
so a description that contradicts the code fails the build rather than reaching this file.

## Links

- Article (how it works, step by step): https://thefintechbuilder.com/technical-indicators/range-and-volatility-indicators/normalized-atr-and-atr-percentage/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/range-and-volatility-indicators/normalized-atr-and-atr-percentage/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt