# Keltner Channels

`D07-F04-A04` · Technical Indicators → Volatility and Channels · archetype `series-transform` · difficulty 3/5 · verification **verified**

Full page: https://docs.thefintechbuilder.com/technical-indicators/volatility-and-channels/keltner-channels/
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 { keltnerChannels } from "fintech-algorithms/technical-indicators/volatility-and-channels/keltner-channels";
```

## Signature

```ts
keltnerChannels(high, low, close, emaPeriod, atrPeriod, multiplier)
```

An EMA with bands placed a number of ATRs away. Because it scales with true range rather than standard deviation, it reacts differently to gaps than Bollinger Bands — which is the basis of the squeeze comparison between the two.

## Parameters

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `high` | `number[]` | yes | Per-bar high prices, chronological. |
| `low` | `number[]` | yes | Per-bar low prices, chronological. |
| `close` | `number[]` | yes | Per-bar closing prices, chronological. |
| `emaPeriod` | `number` | yes | Span of the EMA that forms the middle line. · min: 1, integer: true |
| `atrPeriod` | `number` | yes | Wilder period for the ATR that sets the band width. · min: 1, integer: true |
| `multiplier` | `number` | yes | Number of ATRs from the middle line to each band. · min: 0 |

## Returns

`Record<string, (number | null)[]>` · length same-as-input

Parallel series: `true_range`, `atr`, `middle`, `upper` and `lower`.

## Warm-up

The first `max(emaPeriod, atrPeriod)` positions are `null`.

## Errors

- When either period is < 1, is not an integer, or multiplier is negative — throws RangeError
- When the input series are not all the same length — throws RangeError

## 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

`high`:

```json
[101.08, 101.6243955, 102.13058177, 102.56507653, 102.90321818, 103.1320792]
```

Showing 6 of 240 elements.

`low`:

```json
[98.92, 99.39457765, 99.83203556, 100.19996391, 100.47473988, 100.64442473]
```

Showing 6 of 240 elements.

`close`:

```json
[100, 100.50948657, 100.98130867, 101.38252022, 101.68897903, 101.88825197]
```

Showing 6 of 240 elements.

`emaPeriod`:

```json
20
```

`atrPeriod`:

```json
10
```

`multiplier`:

```json
2
```

### Call

```ts
keltnerChannels(high, low, close, emaPeriod, atrPeriod, multiplier)
```

### Returns

object with 5 fields: true_range, atr, middle, upper, lower

```json
{
  "true_range": [
    2.1599999999999966,
    2.2298178500000034,
    2.298546210000012,
    2.365112620000005,
    2.4284782999999948,
    2.4876544700000096
  ],
  "atr": [null, null, null, null, null, null],
  "middle": [null, null, null, null, null, null],
  "upper": [null, null, null, null, null, null],
  "lower": [null, null, null, null, null, null]
}
```

## Other exports

`trueRange`, `averageTrueRange`. Every module additionally exports `run` as an alias of its primary
function, and a `meta` object carrying its catalog id, domain, family, shape and article URL.

## Verification and provenance

Tier: **verified** (via scenario-fixture).

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@0.13.1.
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/volatility-and-channels/keltner-channels/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/volatility-and-channels/keltner-channels/impl.ts
- Package on npm: https://www.npmjs.com/package/fintech-algorithms
- Domain index for agents: https://docs.thefintechbuilder.com/technical-indicators/llms.txt