---
title: "Contador animado"
description: "Muestra un número que cambia —un recuento, un precio, una puntuación, una cifra de un panel— moviendo cada dígito que cambia hasta su nuevo valor, para que una persona vea que cambió, en qué dirección y aproximadamente cuánto, mientras a la tecnología de apoyo solo se le comunica el valor en el que se detiene."
url: "https://tanrei.chnotchy.com/es/components/number-ticker/"
last_updated: 2026-10-23T21:17:12.000Z
---

# Contador animado

> Muestra un número que cambia —un recuento, un precio, una puntuación, una cifra de un panel— moviendo cada dígito que cambia hasta su nuevo valor, para que una persona vea que cambió, en qué dirección y aproximadamente cuánto, mientras a la tecnología de apoyo solo se le comunica el valor en el que se detiene.

## Descripción general

### Uso

Los ejemplos de Web y React siguen la especificación actual. SwiftUI, Compose, Flutter y React Native están previstos: todavía no incluyen un contador animado.

**Web**

```html
<tanrei-number-ticker value="1234" label="Pedidos"></tanrei-number-ticker>
<tanrei-number-ticker value="98400" number-style="currency" currency="USD" label="Ingresos"></tanrei-number-ticker>

<!-- La cifra de un panel sube desde 0 la primera vez que entra en la vista. -->
<tanrei-number-ticker start-value="0" value="0.426" number-style="percent" fraction-digits="1"></tanrei-number-ticker>

<!-- Un recuento que la persona cambia: se anuncia una vez cuando cada cambio se detiene. -->
<tanrei-number-ticker value="2" live="polite" label="Artículos en el carrito"></tanrei-number-ticker>

<script type="module">
  import '@tanrei/web/components/number-ticker';
  const ticker = document.querySelector('tanrei-number-ticker');
  ticker.value = orders.length;
  ticker.addEventListener('settle', (event) => console.log('now showing', event.detail.value));
</script>
```

**React**

```tsx
import { NumberTicker } from '@tanrei/react';

<NumberTicker value={orders.length} label="Pedidos" />
<NumberTicker value={revenue} numberStyle="currency" currency="USD" label="Ingresos" />
<NumberTicker startValue={0} value={0.426} numberStyle="percent" fractionDigits={1} />
<NumberTicker value={count} live="polite" label="Artículos en el carrito" onSettle={(event) => setShown(event.detail.value)} />
```

## Especificaciones

- Category: Communication
- Level: base
- Listing: default
- Page: https://tanrei.chnotchy.com/components/number-ticker/
- Spec: https://github.com/chnotchy/tanrei/blob/main/specs/number-ticker.spec.json

### Availability

| Design system | Has it | Notes |
| --- | --- | --- |
| Tanrei (`tanrei`) | Yes | — |
| Cupertino (Apple HIG-inspired) (`cupertino`) | Yes | — |
| M3 Expressive-like (Material 3 Expressive-inspired) (`m3-expressive-like`) | Yes | — |
| M3-like (Material 3-inspired) (`m3-like`) | Yes | — |

### Platforms

- Web: the element `<tanrei-number-ticker>`, registered by importing `@tanrei/web` (or only its own module, `@tanrei/web/components/number-ticker`).
- React: `NumberTicker` from `@tanrei/react`.

| Platform | Name | Status |
| --- | --- | --- |
| Web | `tanrei-number-ticker` | alpha |
| SwiftUI | `TanreiNumberTicker` | planned |
| Jetpack Compose | `TanreiNumberTicker` | planned |
| Flutter | `TanreiNumberTicker` | planned |
| React Native | `NumberTicker` | planned |

Names a platform gives in its own idiom:

| Spec | Web | SwiftUI | Jetpack Compose | Flutter | React Native |
| --- | --- | --- | --- | --- | --- |
| `style` (prop) | `numberStyle` | `format` | `format` | `format` | `format` |
| `currency` (prop) | `currency` | `format` | `format` | `format` | `format` |
| `unit` (prop) | `unit` | `format` | `format` | `format` | `format` |
| `notation` (prop) | `notation` | `format` | `format` | `format` | `format` |
| `fractionDigits` (prop) | `fractionDigits` | `format` | `format` | `format` | `format` |
| `signDisplay` (prop) | `signDisplay` | `format` | `format` | `format` | `format` |
| `settle` (event) | `settle` | `onSettle` | `onSettle` | `onSettle` | `onSettle` |

Statuses: `planned` — In the inventory. Nothing shippable exists yet. `lagging` — An implementation of an earlier spec exists; it has not caught up with the current one. `alpha` — Implemented with tests. The API may still change. `beta` — Feature complete and at parity. Only fixes are expected. `stable` — Covered by semantic versioning. `deprecated` — Still shipped; scheduled for removal.

### Anatomy

- `number`: The formatted number, laid out as text in the style of where it stands: every digit in a column of its own, every other character (a sign, a separator, a currency, a unit, a compact suffix) as plain text between them.
- `digit`: One digit's place: a window one digit high showing one digit of a column of the digits 0 to 9 stacked from top to bottom, which moves through the window to show another.
- `text`: The label and the formatted value as one text for assistive technology, not drawn.

### Props

| Prop | Type | Default | Web attribute | Description |
| --- | --- | --- | --- | --- |
| `value` | `number` | `0` | `value` | The number shown. |
| `style` | `enum`: `decimal`, `percent`, `currency`, `unit` | `"decimal"` | — | How the number is written, by the platform's number formatter. percent multiplies by 100 and adds the locale's percent sign; currency writes it as an amount of currency; unit with the unit unit names. |
| `currency` | `string` | `""` | `currency` | The currency while style is currency, as its three-letter code ("JPY", "EUR"). Not words: the formatter writes the locale's symbol. |
| `unit` | `string` | `""` | `unit` | The unit while style is unit, as the formatter's identifier of a unit ("kilometer-per-hour", "megabyte"). Not words: the formatter writes the locale's form. |
| `notation` | `enum`: `standard`, `compact` | `"standard"` | `notation` | standard writes every digit; compact writes the number short with the locale's suffix (1.2K, 1.2万). |
| `fractionDigits` | `number` | — | `fraction-digits` | How many digits after the decimal separator are always written. Null leaves it to the formatter for the style (none for a whole decimal, the currency's own for currency). |
| `signDisplay` | `enum`: `auto`, `always`, `except-zero` | `"auto"` | `sign-display` | When a sign is written: auto for a negative number only; always for every number; except-zero for every number but zero (a change: +12, −3, 0). |
| `locale` | `string` | `""` | `locale` | The language the number is written in, as a language tag ("ja-JP", "ar-EG"). Empty takes the language of where the ticker stands, and the platform's where none is set. |
| `trend` | `enum`: `auto`, `up`, `down`, `digit` | `"auto"` | `trend` | Which way the digits move. auto: every changed digit moves the way the whole number moved — up when it grew, down when it shrank — so that 19 to 20 moves both digits up. up and down force one way. digit: each digit moves the way its own value moved, so that 19 to 20 moves the ones down from 9 to 0. |
| `animation` | `enum`: `auto`, `slide`, `blur`, `blur-slide`, `flip`, `none` | `"auto"` | `animation` | How a digit changes. slide: its column moves through the window. blur: the old digit blurs out as the new one sharpens in. blur-slide: both, the new one coming from the side the digit moves from. flip: the upper half of the old digit turns down over the lower half, as a split-flap board. none: at once. auto takes comp.number-ticker.animation, the design system's answer (slide in the default system). |
| `startValue` | `number` | — | `start-value` | A value to move from the first time the ticker comes into view (a dashboard's figures rising to their values). Null draws the first value at once. |
| `duration` | `number` | — | `duration` | How long a change takes, in milliseconds. Null takes comp.number-ticker.motion.duration. |
| `live` | `enum`: `off`, `polite` | `"off"` | `live` | Whether assistive technology is told each new value as it settles. off for a number that is not the point of the moment (most figures); polite for one a person waits for (a counter they are changing, a result arriving). |
| `label` | `string` | `""` | `label` | Words read before the value ("Revenue"), where nothing visible beside the number already says what it is. Never drawn. |

### Events

| Event | Description |
| --- | --- |
| `settle` | The digits came to rest at value: once at the end of each change's motion (at once where there is none). Carries value. |

### States

`enabled`

### Accessibility

- Role: `none (text)`
- Labeling: Read as one text: label, then the number as the formatter writes it. The drawn digits are hidden. With live polite, the settled value is told once per change.
- Minimum target size: yes

- Not interactive: no focus, no input, no target; minimumTarget holds trivially.
- Live regions: a number that is not the point of the moment is told nothing (off); one a person waits for is told politely once it settles, never each value it passes through.
- Pause, Stop, Hide (WCAG 2.2.2): one change's motion ends well within five seconds. A number the product updates by itself, again and again, alongside other content is auto-updating content: the product gives the means to pause the updates, or to set how often they come.
- Animation from interactions (WCAG 2.3.3): where motion is reduced, the number changes at once (NTK-7).

### Behaviour

Requirements in EARS form, each with its stable id.

- **NTK-1** THE number ticker SHALL write value with the platform's number formatter in locale (the language of where it stands while locale is empty), with style, currency, unit, notation, fractionDigits and signDisplay, SHALL draw every digit of the result — in the locale's own digits — in a digit place of its own, in tabular figures of the font of where it stands so that every digit is as wide as every other, and every other character the formatter writes as plain text in that font; it SHALL lay the number out inline, in the text style, color and direction of where it stands, as one run isolated from the text around it, and SHALL draw no fill, edge or color of its own.
- **NTK-2** THE number ticker SHALL draw each digit place as a window one line high that shows one digit of a column of the locale's digits 0 to 9 stacked from top to bottom, clipped to the window, so that a greater digit lies lower in the column; to show a digit the column SHALL stand with that digit in the window.
- **NTK-3** WHEN value changes while animation is slide THE number ticker SHALL move the column of every digit place whose digit changes from the old digit to the new one: WHILE trend is digit, down the column toward a greater digit (the column moving up through the window, the new digit rising from below) and up it toward a lesser one; WHILE trend is auto, every changed digit in the direction the whole number moved — toward the greater digits when value grew and toward the lesser when it shrank — going on past 9 to 0 (or back past 0 to 9) where the new digit lies the other way, so that 19 to 20 moves the ones one step on from 9 to 0 and the tens one step on from 1 to 2; WHILE trend is up or down, every changed digit in that direction as auto does for a number that grew or shrank. Each column SHALL move over the change's duration (duration, or comp.number-ticker.motion.duration while it is null) with comp.number-ticker.motion.easing, each digit place, from the most significant to the least, starting comp.number-ticker.motion.stagger after the one before it.
- **NTK-4** WHEN value changes while animation is blur THE number ticker SHALL cross-fade each changed digit over the change's duration, the old digit blurring from none to comp.number-ticker.blur.radius as it fades out and the new one sharpening from that radius to none as it fades in; WHILE animation is blur-slide it SHALL do the same while moving the old digit out and the new one in by comp.number-ticker.blur-slide.distance in the direction slide would (NTK-3); WHILE animation is flip it SHALL turn the upper half of the old digit down about the digit's middle over the lower half, showing the upper half of the new digit behind it and then its lower half, as a split-flap board, over the change's duration with comp.number-ticker.motion.easing.
- **NTK-5** WHEN the formatted number gains or loses characters (99 to 100, 999 to 1,000, a sign that appears) THE number ticker SHALL move its width to the new one with the digits' motion, keeping its end edge still WHILE it is aligned to the end of where it stands and its start edge still otherwise; a digit place that appears SHALL slide in with its column from the side the change moves from and fade in, one that goes SHALL slide out the other way and fade out, and a character that is not a digit SHALL fade in or out in its place.
- **NTK-6** WHEN value changes again before a change's motion has ended THE number ticker SHALL move every digit place from where it is drawn at that moment to the new digit, by the rule of NTK-3 for the new change, and SHALL never jump to a digit first; the change's duration SHALL start again from that moment.
- **NTK-7** WHERE motion is reduced, or WHILE animation is none, THE number ticker SHALL show the new number at once, its width included — cross-fading the old number to the new one over comp.number-ticker.motion.reduced-duration where motion is reduced and the platform can fade — and SHALL emit settle at once.
- **NTK-8** WHEN the ticker first comes into view WHILE startValue is not null THE number ticker SHALL draw startValue and move to value as a change of NTK-3 and NTK-4, once; WHILE startValue is null, and on every later first drawing, it SHALL draw value at once without a motion.
- **NTK-9** THE number ticker SHALL expose to assistive technology one text — label where it is not empty, then the number written as NTK-1 says — and SHALL hide every drawn digit, column and character from it, so that the number is read once, as written, and never digit by digit or as the digits passing through the windows; the text SHALL be the current value, in place, read where the ticker stands — WHILE live is polite, the value of the last change that settled (NTK-10).
- **NTK-10** WHILE live is polite THE number ticker SHALL tell assistive technology the text of NTK-9, politely and without moving focus, once WHEN a change's motion ends — the text itself changing only then, so that what a region holds is what it says — and SHALL tell it no value in between, nor any value of a change that a later change replaced before it ended; WHILE live is off it SHALL tell it nothing by itself.
- **NTK-11** WHEN the digits come to rest at value THE number ticker SHALL emit settle once with value; a change that a later change replaces before its end SHALL emit none.
- **NTK-12** IF value is not a finite number THE number ticker SHALL draw what the formatter writes for it (the locale's sign for infinity, or its word for a value that is not a number) as plain text at once, without a motion, and in debug builds report it; IF style is currency and currency is not a code the formatter knows, or style is unit and unit is not a unit it knows, THE number ticker SHALL write the number as decimal and in debug builds report the value.
- **NTK-13** WHERE the layout direction is right-to-left THE number ticker SHALL lay out the number as the formatter writes it for its locale — digits in the order the locale writes them, which is left to right in every locale, isolated from the text around it — and SHALL move its columns up and down as in a left-to-right layout; only the side it stands at and the edge NTK-5 keeps still follow the direction.
- **NTK-14** THE number ticker SHALL take its layout direction and its language from where it is used — the nearest ancestor that sets one, and the platform's own where none does — and SHALL have no direction setting of its own; WHEN either changes while the ticker is shown THE number ticker SHALL write and draw the number for the new one at once, without a motion.
- **NTK-15** WHILE the text size is enlarged THE number ticker SHALL grow with the text it stands in, its windows a line of the larger text high and its motion's distances with them.
- **NTK-16** WHEN animation names a value the active design system does not have, or trend, style, notation, signDisplay or live a value the component does not define, THE number ticker SHALL use the default value (auto, decimal, standard, auto, off) and in debug builds report the unknown value; WHEN duration is not a positive number, or fractionDigits not a whole number from 0 to 100, THE number ticker SHALL treat it as null and in debug builds report it.
- **NTK-17** THE number ticker SHALL have no words of its own and SHALL read none of the product's words: label is about this one number, and every sign, separator, symbol and suffix is the platform's formatter's, in the locale.

### Tokens

As written in the token documents (DTCG): an alias in braces names the token it takes its value from, which each design system resolves. On the web each token is a CSS custom property: `--tanrei` and the name after `tanrei`, joined by hyphens (`tanrei.comp.number-ticker.…` → `--tanrei-comp-number-ticker-…`).

#### `tanrei.comp.number-ticker`

| Token | Type | Value |
| --- | --- | --- |
| `comp.number-ticker.animation` | `number` | `0` |
| `comp.number-ticker.motion.duration` | `duration` | `{tanrei.sys.motion.role.resize.large}` |
| `comp.number-ticker.motion.easing` | `cubicBezier` | `{tanrei.sys.motion.easing.spatial}` |
| `comp.number-ticker.motion.stagger` | `duration` | `{tanrei.sys.motion.duration.short1}` |
| `comp.number-ticker.motion.reduced-duration` | `duration` | `{tanrei.sys.motion.role.reduced}` |
| `comp.number-ticker.blur.radius` | `dimension` | `{tanrei.sys.space.space100}` |
| `comp.number-ticker.blur-slide.distance` | `dimension` | `{tanrei.sys.space.space100}` |

## Pautas

### Cuándo usarlo

Usa un contador animado para un número que cambia mientras una persona lo mira, cuando el propio cambio merece verse: un recuento que sube a medida que llegan pedidos, un precio que se mueve, una puntuación, las cifras de un panel que suben hasta su valor cuando se abre la página. El movimiento muestra que el número cambió, en qué dirección y aproximadamente cuánto.

Un número que cambia pocas veces, o que nadie mira cambiar, es texto normal. Un nivel dentro de un intervalo conocido —el almacenamiento usado de una cuota— es un [medidor](https://tanrei.chnotchy.com/es/components/meter/). Las horas y las fechas no son números: escríbelas con el formato de fecha y hora de la plataforma.

### Cómo se escribe el número

El contador no tiene palabras ni reglas numéricas propias. El formateador de números de la plataforma lo escribe en el idioma del lector: los separadores de miles y decimales, el símbolo de la moneda, el signo de porcentaje, la forma corta de un número grande (1,2 mil, 1.2万) y los propios dígitos (١٢٣٤ en árabe tal como se escribe en Egipto). Elige un estilo (decimal, percent, currency o unit), un código de moneda o una unidad, la notación compacta, un número fijo de decimales y cuándo escribir el signo; si no indicas un idioma, toma el del lugar donde está.

Tampoco tiene tipografía, tamaño ni color: se dibuja con el estilo de texto del lugar donde lo colocas, con cifras de igual ancho para que el número no se desplace cuando cambian sus dígitos. Puede ser la cifra grande de una tarjeta de un panel o un recuento dentro de una frase.

### Cómo elegir una animación

| Animación | Uso |
| --- | --- |
| Slide | La mayoría de los números. La columna de cada dígito que cambia gira hasta su nuevo dígito. La elección del sistema predeterminado. |
| Blur | Un cambio más discreto: el dígito anterior se desenfoca y se desvanece mientras el nuevo aparece nítido. |
| Blur slide | Lo mismo, con los dígitos desplazándose un poco en la dirección del cambio. |
| Flip | Un panel de paletas: salidas, una cuenta atrás, un producto de aspecto mecánico. |
| None | Un número que debe cambiar de inmediato. |

Mantén una sola animación en todo tu producto: defínela una vez en el sistema de diseño (`comp.number-ticker.animation`) en lugar de en cada contador.

### Cómo elegir el trend

De forma predeterminada, cada dígito que cambia se mueve en la dirección en que se movió el número completo: hacia arriba si creció, hacia abajo si disminuyó, de modo que de 19 a 20 ambos dígitos suben. Así se lee como un cambio de un número. Elige `digit` cuando cada posición significa algo por sí misma: cada dígito se mueve entonces según su propio cambio, y las unidades bajan de 9 a 0. `up` y `down` fijan una dirección, para un número que solo cuenta en un sentido.

### Recomendado

- Colócalo dentro del texto, o da a su contenedor el estilo de texto que quieras. Toma todo de ahí.
- Añade una etiqueta cuando nada visible junto al número diga qué es: «Ingresos», «Pedidos».
- Deja live desactivado en las cifras que cambian solas. Actívalo solo para un número que la persona espera o está cambiando.
- Usa el valor inicial en un panel para que sus cifras suban una vez, la primera vez que se ven.

### Evita

- No colorees una subida de verde ni una bajada de rojo a través del contador: no tiene esos colores. Si un cambio significa algo, dilo junto al número: una etiqueta, una palabra, una flecha con texto.
- No actualices un número varias veces por segundo. Cada cambio dura lo que dura el movimiento; una sucesión de cambios se percibe como ruido. Actualízalo al ritmo que una persona puede seguir.
- No lo uses para la hora. Los dígitos de un reloj pasan a cero en 59, no en 9.

## Accesibilidad

### De qué se encarga el componente

- La tecnología de apoyo lee un solo texto: la etiqueta y, después, el número tal como lo escribe el formateador. Los dígitos dibujados están ocultos, así que el número nunca se lee dígito a dígito ni como los dígitos que pasan por sus ventanas.
- De forma predeterminada no se anuncia nada: la mayoría de las cifras no son lo principal en ese momento. Con live en polite, el número se anuncia de forma educada una vez cuando cada cambio se detiene, nunca un valor por el que pasa ni uno que un cambio posterior sustituyó.
- Cuando se pide movimiento reducido, el número nuevo aparece al instante y el anterior se desvanece brevemente.
- Toma el idioma y la dirección del lugar donde está, y vuelve a escribir el número al instante cuando cambia cualquiera de los dos.
- En las compilaciones de depuración se informa de un valor desconocido de animation, trend, style, notation, sign display o live, de una duration que no es positiva, de una moneda o unidad que el formateador no conoce y de un valor que no es un número.

### Qué debes hacer tú

- Si tu producto actualiza un número por sí solo una y otra vez junto a otro contenido, ofrece una forma de pausar las actualizaciones o de elegir con qué frecuencia llegan (WCAG 2.2.2 Pausar, detener, ocultar).
- Explica con palabras lo que significa un cambio cuando importa. El movimiento muestra que cambió; no dice si es bueno o malo.