# High-Low Range Percentage

`D07-F06-A10` · 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/high-low-range-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 { highLowRangePercentage } from "fintech-algorithms/technical-indicators/range-and-volatility-indicators/high-low-range-percentage";
```

## Signature

```ts
highLowRangePercentage(input)
```

Expresses the bar's high-low range as a percentage of its high-low midpoint: `200 * (high - low) / (high + low)`.

## 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. This topic reads no keys of its own from `parameters`, but the family still validates `period` (default 14, integer >= 2) before the branch runs, so an invalid `period` is rejected here too. |

## Returns

`TopicResult`

`series` holds a single key, `value`, the per-bar range percentage; `latest.value` is the last bar's reading. There is no warm-up -- the calculation is per-bar, so `ready_at` is 0.

## Warm-up

The first `0 bars` positions are `not applicable`. Every bar is self-contained, so `value` is populated from index 0. The only null case is a bar where `high + low` is exactly 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
highLowRangePercentage(input)
```

### Returns

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

```json
{
  "topic_id": "D07-F06-A10",
  "title": "High-Low Range Percentage",
  "state": "calculated",
  "ready": true,
  "ready_at": 0,
  "series": {
    "value": [
      2.753004072047775,
      3.272748071764005,
      3.6566626050949482,
      3.82208970566863,
      3.7288541366298587,
      3.392411654116297
    ]
  },
  "latest": {
    "value": 3.1131062534873144
  },
  "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/high-low-range-percentage/
- Implementation source: https://github.com/IslamBaraka90/Fintech-Algorithms-Library/blob/main/src/technical-indicators/range-and-volatility-indicators/high-low-range-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