Web Animations Easy

Scroll-Linked Number Counters

Numeric metrics animate from 0 to target as you scroll. Counter speed is directly linked to scroll position using GSAP ScrollTrigger scrub.

Open in Lab

gsap scrolltrigger textplugin lenis

Targets: JS HTML

Code

:root {
  --bg: #070a12;
  --text: #f0f4fb;
  --panel: #121a2b;
  --border: #263249;
  --accent: #86e8ff;
  --muted: #8a95a8;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

/* Hero Section */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  background: linear-gradient(135deg, rgba(134, 232, 255, 0.05) 0%, rgba(174, 82, 255, 0.05) 100%);
}

.hero .content {
  max-width: 600px;
  text-align: center;
}

.eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 1.5rem;
  letter-spacing: -1px;
}

.subtitle {
  font-size: 1.1rem;
  color: var(--muted);
  max-width: 500px;
  margin: 0 auto;
}

/* Metrics Section */
.metrics-section {
  padding: 6rem 2rem;
  background: rgba(134, 232, 255, 0.02);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.metrics-grid {
  max-width: 1000px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
}

.metric-card {
  padding: 2.5rem 2rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  text-align: center;
  transition: all 0.3s ease;
}

.metric-card:hover {
  background: rgba(134, 232, 255, 0.08);
  border-color: var(--accent);
  transform: translateY(-2px);
}

.metric-card.scrolling {
  background: rgba(134, 232, 255, 0.12);
  border-color: var(--accent);
}

.metric-value {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--accent);
  margin-bottom: 0.5rem;
  display: inline;
}

.metric-unit {
  font-size: 1rem;
  color: var(--muted);
  margin-left: 0.25rem;
}

.metric-label {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  margin-top: 1rem;
  margin-bottom: 0.5rem;
}

.metric-subtext {
  font-size: 0.85rem;
  color: var(--muted);
}

/* Details Section */
.details-section {
  max-width: 800px;
  margin: 4rem auto;
  padding: 4rem 2rem;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: rgba(18, 26, 43, 0.8);
}

.content {
  max-width: 800px;
  margin: 0 auto;
}

.details-section h2,
.final-section h2 {
  font-size: 1.8rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
  color: var(--text);
}

.details-section h3 {
  font-size: 1.2rem;
  margin-top: 1.5rem;
  margin-bottom: 0.8rem;
  color: var(--accent);
}

.details-section p,
.final-section p {
  font-size: 1rem;
  color: var(--muted);
  margin-bottom: 1.5rem;
  line-height: 1.8;
}

code {
  background: rgba(134, 232, 255, 0.1);
  color: var(--accent);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  font-family: "Monaco", "Courier New", monospace;
  font-size: 0.9rem;
}

.details-section ul,
.final-section ol {
  margin-left: 1.5rem;
  margin-bottom: 1.5rem;
}

.details-section li,
.final-section li {
  color: var(--muted);
  margin-bottom: 0.8rem;
  line-height: 1.7;
}

.details-section li strong {
  color: var(--accent);
}

/* Final Section */
.final-section {
  max-width: 800px;
  margin: 0 auto;
  padding: 4rem 2rem;
}

/* Button */
.btn-back {
  display: inline-block;
  margin-top: 2rem;
  padding: 0.8rem 1.5rem;
  background: var(--accent);
  color: var(--bg);
  border: none;
  border-radius: 4px;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s ease;
}

.btn-back:hover {
  background: rgba(134, 232, 255, 0.8);
  transform: translateY(-2px);
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.5rem;
  }

  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
  }

  .metric-card {
    padding: 1.5rem 1rem;
  }

  .metric-value {
    font-size: 2rem;
  }

  .details-section {
    margin: 2rem auto;
    padding: 2rem 1.5rem;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 2rem;
  }

  .subtitle {
    font-size: 1rem;
  }

  .metrics-grid {
    grid-template-columns: 1fr;
  }

  .metric-value {
    font-size: 1.8rem;
  }
}

html.reduced-motion .metric-card,
html.reduced-motion .hero,
html.reduced-motion .details-section,
html.reduced-motion .final-section {
  animation: none !important;
}

html.reduced-motion * {
  animation-duration: 0.01ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.01ms !important;
}

if (!window.MotionPreference) {
  const __mql = window.matchMedia("(prefers-reduced-motion: reduce)");
  const __listeners = new Set();

  const MotionPreference = {
    prefersReducedMotion() {
      return __mql.matches;
    },
    setOverride(value) {
      const reduced = Boolean(value);
      document.documentElement.classList.toggle("reduced-motion", reduced);
      window.dispatchEvent(new CustomEvent("motion-preference", { detail: { reduced } }));
      for (const listener of __listeners) {
        try {
          listener({ reduced, override: reduced, systemReduced: __mql.matches });
        } catch {}
      }
    },
    onChange(listener) {
      __listeners.add(listener);
      try {
        listener({
          reduced: __mql.matches,
          override: null,
          systemReduced: __mql.matches,
        });
      } catch {}
      return () => __listeners.delete(listener);
    },
    getState() {
      return { reduced: __mql.matches, override: null, systemReduced: __mql.matches };
    },
  };

  window.MotionPreference = MotionPreference;
}

function prefersReducedMotion() {
  return window.MotionPreference.prefersReducedMotion();
}

function initDemoShell() {
  // No-op shim in imported standalone snippets.
}

import gsap from "gsap";
import { ScrollTrigger } from "gsap/ScrollTrigger";
import { TextPlugin } from "gsap/TextPlugin";
import Lenis from "lenis";

gsap.registerPlugin(ScrollTrigger, TextPlugin);

initDemoShell({
  title: "Scroll-Linked Number Counters",
  category: "scroll",
  tech: ["gsap", "scrolltrigger", "textplugin"],
});

const lenis = new Lenis({ lerp: 0.1, smoothWheel: true });
lenis.on("scroll", ScrollTrigger.update);
gsap.ticker.add((time) => lenis.raf(time * 1000));
gsap.ticker.lagSmoothing(0);

const reduced = prefersReducedMotion();
if (reduced) document.documentElement.classList.add("reduced-motion");

// Intro animation
if (!reduced) {
  gsap.set(".hero .eyebrow", { opacity: 0, y: 20 });
  gsap.set(".hero h1", { opacity: 0, y: 40 });
  gsap.set(".hero .subtitle", { opacity: 0, y: 25 });

  gsap
    .timeline({ defaults: { ease: "expo.out" } })
    .to(".hero .eyebrow", { opacity: 1, y: 0, duration: 0.7, delay: 0.3 })
    .to(".hero h1", { opacity: 1, y: 0, duration: 0.9 }, "-=0.4")
    .to(".hero .subtitle", { opacity: 1, y: 0, duration: 0.7 }, "-=0.5");
}

// Counter animation configuration
const metricCards = document.querySelectorAll(".metric-card");

metricCards.forEach((card, index) => {
  const valueEl = card.querySelector(".metric-value");
  const target = parseFloat(valueEl.dataset.target);

  if (!reduced) {
    // Entrance animation
    gsap.set(card, { opacity: 0, y: 40 });
    gsap.to(card, {
      opacity: 1,
      y: 0,
      duration: 0.8,
      ease: "expo.out",
      delay: 0.1 * index,
      scrollTrigger: {
        trigger: card,
        start: "top 85%",
        toggleActions: "play none none reverse",
      },
    });
  }

  // Counter animation — synced to scroll
  gsap.to(valueEl, {
    text: target,
    duration: 1.5,
    ease: "power1.inOut",
    snap: { text: 1 }, // Only update on integer changes
    scrub: 1, // Link directly to scroll position
    scrollTrigger: {
      trigger: card,
      start: "top 80%",
      end: "top 30%",
      onUpdate: (self) => {
        // Optional: add visual feedback during scroll
        if (self.direction === 1) {
          card.classList.add("scrolling");
        }
      },
    },
  });

  // Remove scrolling class when done
  ScrollTrigger.create({
    trigger: card,
    start: "top 30%",
    onLeave: () => card.classList.remove("scrolling"),
    onEnterBack: () => card.classList.add("scrolling"),
  });
});

// Section reveals
document
  .querySelectorAll(".details-section h2, .details-section h3, .final-section h2")
  .forEach((el) => {
    if (!reduced) {
      gsap.set(el, { opacity: 0, y: 30 });
      gsap.to(el, {
        opacity: 1,
        y: 0,
        duration: 0.7,
        ease: "expo.out",
        scrollTrigger: { trigger: el, start: "top 75%", toggleActions: "play none none reverse" },
      });
    }
  });

document
  .querySelectorAll(".details-section p, .details-section ul, .final-section p, .final-section ol")
  .forEach((el) => {
    if (!reduced) {
      gsap.set(el, { opacity: 0, y: 20 });
      gsap.to(el, {
        opacity: 1,
        y: 0,
        duration: 0.6,
        ease: "expo.out",
        scrollTrigger: { trigger: el, start: "top 75%", toggleActions: "play none none reverse" },
      });
    }
  });

// Motion preference listener
window.addEventListener("motion-preference", (e) => {
  if (e.detail.reduced) {
    // Pause all animations
    gsap.globalTimeline.paused(true);
  } else {
    // Resume
    gsap.globalTimeline.paused(false);
  }
});

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Scroll-Linked Number Counters — stealthisdesign</title>
  <link rel="stylesheet" href="style.css">
    <script type="importmap">{"imports":{"gsap":"https://esm.sh/gsap@3.13.0","gsap/ScrollTrigger":"https://esm.sh/gsap@3.13.0/ScrollTrigger","gsap/SplitText":"https://esm.sh/gsap@3.13.0/SplitText","gsap/Flip":"https://esm.sh/gsap@3.13.0/Flip","gsap/ScrambleTextPlugin":"https://esm.sh/gsap@3.13.0/ScrambleTextPlugin","gsap/TextPlugin":"https://esm.sh/gsap@3.13.0/TextPlugin","gsap/all":"https://esm.sh/gsap@3.13.0/all","gsap/":"https://esm.sh/gsap@3.13.0/","lenis":"https://esm.sh/lenis@1.1.13/dist/lenis.mjs","three":"https://esm.sh/three@0.171.0","three/addons/":"https://esm.sh/three@0.171.0/examples/jsm/"}}</script>
  <style>html.lenis,
html.lenis body {
  height: auto;
}

.lenis:not(.lenis-autoToggle).lenis-stopped {
  overflow: clip;
}

.lenis [data-lenis-prevent],
.lenis [data-lenis-prevent-wheel],
.lenis [data-lenis-prevent-touch] {
  overscroll-behavior: contain;
}

.lenis.lenis-smooth iframe {
  pointer-events: none;
}

.lenis.lenis-autoToggle {
  transition-property: overflow;
  transition-duration: 1ms;
  transition-behavior: allow-discrete;
}</style>
</head>
<body>
  <section class="hero">
    <div class="content">
      <span class="eyebrow">Demo 36</span>
      <h1>Scroll-Linked Number Counters</h1>
      <p class="subtitle">Numeric metrics animate from 0 to target as you scroll. Metrics update in real-time, synced with scroll position using GSAP ScrollTrigger.</p>
    </div>
  </section>

  <section class="metrics-section">
    <div class="metrics-grid">
      <div class="metric-card">
        <div class="metric-value" data-target="1250">0</div>
        <div class="metric-label">Projects Completed</div>
        <div class="metric-subtext">Enterprise clients worldwide</div>
      </div>

      <div class="metric-card">
        <div class="metric-value" data-target="98.5">0</div>
        <div class="metric-unit">%</div>
        <div class="metric-label">Client Satisfaction</div>
        <div class="metric-subtext">Based on 500+ reviews</div>
      </div>

      <div class="metric-card">
        <div class="metric-value" data-target="15">0</div>
        <div class="metric-label">Years Experience</div>
        <div class="metric-subtext">In web and animation</div>
      </div>

      <div class="metric-card">
        <div class="metric-value" data-target="2.3">0</div>
        <div class="metric-unit">M+</div>
        <div class="metric-label">Lines of Code</div>
        <div class="metric-subtext">Written and deployed</div>
      </div>
    </div>
  </section>

  <section class="details-section">
    <div class="content">
      <h2>How It Works</h2>
      <p>This technique uses GSAP's <code>TextPlugin</code> combined with <code>ScrollTrigger</code> to animate numeric values from 0 to a target number while the user scrolls. The counter respects <code>scrub: true</code>, meaning the animation is directly linked to scroll position — scroll faster, the numbers update faster.</p>

      <h3>Key Features</h3>
      <ul>
        <li><strong>Scroll-synced:</strong> Counter animation is tied directly to scroll progress using <code>scrub</code></li>
        <li><strong>Decimal support:</strong> Handles percentages, decimals, and large numbers with thousand separators</li>
        <li><strong>Staggered reveal:</strong> Each card animates in sequence as you scroll past</li>
        <li><strong>Reduced motion:</strong> Counters are skipped if user prefers no motion</li>
        <li><strong>Performance optimized:</strong> Uses integer rendering to avoid excessive DOM updates</li>
      </ul>

      <h3>Use Cases</h3>
      <p>Perfect for:</p>
      <ul>
        <li>Portfolio showcase pages (project counts, years of experience)</li>
        <li>SaaS landing pages (user counts, uptime metrics)</li>
        <li>Case studies (improvement percentages, revenue impact)</li>
        <li>Company stats pages (customers served, transactions processed)</li>
      </ul>
    </div>
  </section>

  <section class="final-section">
    <div class="content">
      <h2>Integration Tips</h2>
      <p>To use this in your own projects:</p>
      <ol>
        <li>Import GSAP and TextPlugin: <code>import { TextPlugin } from 'gsap/TextPlugin'</code></li>
        <li>Register the plugin: <code>gsap.registerPlugin(TextPlugin)</code></li>
        <li>Use <code>scrub: true</code> to link animation to scroll position</li>
        <li>Customize formatting with <code>formatUnits</code> callback for decimals/prefixes</li>
        <li>Wrap in <code>ScrollTrigger</code> to trigger when card enters viewport</li>
      </ol>
      <a href="/" class="btn-back">Back to Showcase</a>
    </div>
  </section>

  <script type="module" src="script.js"></script>
</body>
</html>

Scroll-Linked Number Counters

Numeric metrics animate from 0 to target as you scroll. Counter speed is directly linked to scroll position using GSAP ScrollTrigger scrub.

Source

Repository: libs-genclaude
Original demo id: 36-scroll-linked-counters

Notes

Numeric metrics animate from 0 to target as you scroll. Counter speed is directly linked to scroll position using GSAP ScrollTrigger scrub.