# Meter card

> Canonical HTML: https://screenrig.ai/docs/cards/meter/

A bar or ring that fills towards a goal, with its value, unit and optional label.

A bare bar or ring fills towards its goal, with the value in large figures, its unit beside it and an optional label, so the measure reads at a glance from across a room. It fills the screen, sits in the middle, tucks into a corner, runs as one line in a corner or stretches as a band along an edge. You set the value, its goal and an optional label, with a currency symbol or unit beside the figure. You choose a bar or a ring and the warning and danger levels where its fill colour changes, for measures where higher is better or worse.

## Live card

This card is drawn in your browser by the same code the Players run, with sample data.

Category: Operations. Tags: Numbers and metrics, Charts and gauges.

## Layouts

This core card fits every layout: full screen, center, corner, chip, strip, or any free rectangle.

Layouts: full, center, corner, chip, strip. Forms: landscape, portrait, square, strip.

[Card layouts, themes and publishing](/docs/cards/). [Browse the cards](/apps/#cards).

## Data and privacy

This card uses its configured properties and live card data.

## Properties

For theme, background, accent and position, see [Common properties](/docs/cards/#common-properties).

Set static properties in `params`. Bind `data` to a project card data key for live values; that document holds only dynamic properties. Without a data key, put the complete configuration in `params`. Nested rows describe the contents of their parent property.

### Static properties

| Name | Type | Default | Values and limits | Description |
| --- | --- | --- | --- | --- |
| `prefix` | string | `""` | maxLength: `8` | Before the value, smaller: a currency symbol. |
| `suffix` | string | `""` | maxLength: `12` | After the value, smaller: a unit (%, kW, GB). |
| `style` | string | `"bar"` | `"bar"`, `"ring"` | A bar across the box or a ring with the value inside. |
| `decimals` | integer, null | `null` | minimum: `0`; maximum: `4` | Decimals to show; null shows only the ones the value needs, up to one. |
| `grouping` | boolean | `true` |  | Group thousands with commas. |
| `tone` | string | `"cool"` | `"success"`, `"warm"`, `"danger"`, `"cool"`, `"accent"`, `"muted"` | The fill colour, a palette key, when no threshold is set. |
| `warnAt` | number, null | `null` | minimum: `0`; maximum: `1000` | Percent of the goal at which the fill turns warm: under it when goodWhen is up, over it when down. |
| `dangerAt` | number, null | `null` | minimum: `0`; maximum: `1000` | Percent of the goal at which the fill turns danger: under it when goodWhen is up, over it when down. |
| `goodWhen` | string | `"up"` | `"up"`, `"down"` | Whether a higher value is better (battery, sales) or worse (disk use, queue length). |

### Dynamic properties

| Name | Type | Default | Values and limits | Description |
| --- | --- | --- | --- | --- |
| `value` | number, null | `null` | minimum: `-1000000000000000.0`; maximum: `1000000000000000.0` | The measured value. null shows a dash and an empty bar. |
| `goal` | number | `100` | maximum: `1000000000000000.0`; exclusiveMinimum: `0` | What the value is measured against: the full bar or ring. |
| `previous` | number, null | `null` | minimum: `-1000000000000000.0`; maximum: `1000000000000000.0` | The value before the latest change. With changedAt, every screen counts and fills from it to the new value together. |
| `changedAt` | string, null | `null` | maxLength: `40` | ISO 8601 instant the value changed. |
| `label` | string | `""` | maxLength: `40` | A short name for the measure, in the theme's tag. |

## Canvas example

Add this item to a playlist page’s `primitives`. [Publish the playlist and assign a screen](/docs/cards/#publish-a-card-canvas).

```json
{
  "id": "meter",
  "primitive": "card",
  "card": "meter",
  "major": 1,
  "params": {
    "theme": "neomustard"
  },
  "rect": {
    "x": 0,
    "y": 0,
    "width": 1920,
    "height": 1080
  },
  "layer": 0,
  "content_fit": "fill",
  "data": "example-key"
}
```

## Write live data

The canvas example binds its `data` field to `example-key`. That value is a data key: a name this canvas item chooses, not the name of the card. Give each canvas item its own key when items should show different data, or share one key when they should show the same data. Keys are scoped to the project, follow the K/V key grammar, and cannot start with `feed:`.

Create this document before showing the card, then replace it to update the screen without republishing. Writes to a key that live canvas items bind are checked against each bound card’s dynamic properties. Use the same project as the playlist.

Save the document as `card-data.json`. The CLI reads the document itself, with no wrapper:

```json
{
  "value": null,
  "goal": 100,
  "previous": null,
  "changedAt": null,
  "label": ""
}
```

```console
screenrig card-data put example-key --file card-data.json
```

Or call the API directly. The API wraps the same document in a `document` field. An agent token already names its project, so no project header is sent; if you send `ScreenRig-Project`, it must match the token’s project. Supply your API authorization through the environment; see [API authentication](/docs/authentication/).

```console
curl --request PUT "https://api.screenrig.ai/api/card-data/example-key" \
  --header "Authorization: Bearer $SCREENRIG_TOKEN" \
  --header "Content-Type: application/json" \
  --data '{"document":{"value":null,"goal":100,"previous":null,"changedAt":null,"label":""}}'
```