diff --git a/static/base.css b/static/base.css
index 5118f27..f2b59de 100644
--- a/static/base.css
+++ b/static/base.css
@@ -59,6 +59,14 @@ button {
     background-color: var(--color-panel-background);
 }
 
+button.icon {
+    border: none;
+    border-radius: 0;
+    padding: 0;
+    width: 24px;
+    height: 24px;
+}
+
 /* Text areas */
 
 input {
@@ -66,7 +74,7 @@ input {
     border-bottom: 1px solid var(--color-panel-border);
 }
 
-*:focus {
+*:focus-visible {
     outline: 1px solid var(--color-brand-blue);
     outline-offset: 4px;
 }
@@ -172,6 +180,8 @@ pre:has(code) {
     --icon-memory: url("data:image/svg+xml;base64,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");
     --icon-object: url("data:image/svg+xml;base64,PHN2ZyBmaWxsPSJub25lIiBoZWlnaHQ9IjE2IiB2aWV3Qm94PSIwIDAgMTYgMTYiIHdpZHRoPSIxNiIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48cGF0aCBjbGlwLXJ1bGU9ImV2ZW5vZGQiIGQ9Im0xMiA2YzAgMS4xMDQ1Ny0uODk1NCAyLTIgMnYyYzIuMjA5MSAwIDQtMS43OTA4NiA0LTRzLTEuNzkwOS00LTQtNGMtMi4yMDkxNCAwLTQgMS43OTA4Ni00IDRoMmMwLTEuMTA0NTcuODk1NDMtMiAyLTIgMS4xMDQ2IDAgMiAuODk1NDMgMiAyeiIgZmlsbD0iIzAwMCIgZmlsbC1ydWxlPSJldmVub2RkIi8+PHBhdGggZD0ibTMgN2g2djZoLTZ6IiBzdHJva2U9IiMwMDAiIHN0cm9rZS13aWR0aD0iMiIvPjwvc3ZnPg==");
     --icon-rkgk-grayscale: url("data:image/svg+xml;base64,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");
+    --icon-plus: url("data:image/svg+xml;base64,PHN2ZyBmaWxsPSJub25lIiBoZWlnaHQ9IjE2IiB2aWV3Qm94PSIwIDAgMTYgMTYiIHdpZHRoPSIxNiIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48ZyBmaWxsPSIjMDAwIj48cGF0aCBkPSJtNyA0aDJ2OGgtMnoiLz48cGF0aCBkPSJtNCA3aDh2MmgtOHoiLz48L2c+PC9zdmc+");
+    --icon-minus: url("data:image/svg+xml;base64,PHN2ZyBmaWxsPSJub25lIiBoZWlnaHQ9IjE2IiB2aWV3Qm94PSIwIDAgMTYgMTYiIHdpZHRoPSIxNiIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48cGF0aCBkPSJtNCA3aDh2MmgtOHoiIGZpbGw9IiMwMDAiLz48L3N2Zz4=");
 
     --icon-brackets-white: url("data:image/svg+xml;base64,PHN2ZyBmaWxsPSJub25lIiBoZWlnaHQ9IjE2IiB2aWV3Qm94PSIwIDAgMTYgMTYiIHdpZHRoPSIxNiIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48cGF0aCBkPSJtNyA0aC0zdjhoM20yLThoM3Y4aC0zIiBzdHJva2U9IiNmZmYiIHN0cm9rZS13aWR0aD0iMiIvPjwvc3ZnPg==");
     --icon-droplet-white: url("data:image/svg+xml;base64,PHN2ZyBmaWxsPSJub25lIiBoZWlnaHQ9IjE2IiB2aWV3Qm94PSIwIDAgMTYgMTYiIHdpZHRoPSIxNiIgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIj48cGF0aCBkPSJtNSAxMGMwLTEuNjM0NzIgMS4wMDIxMi00LjI3MTU2IDIuMTg3MjYtNi41NDUzNy4zNDg5My0uNjY5NDQgMS4yNzY1NS0uNjY5NDQgMS42MjU0OCAwIDEuMTg1MTQgMi4yNzM4MSAyLjE4NzI2IDQuOTEwNjUgMi4xODcyNiA2LjU0NTM3IDAgMi0xLjUgMy0zIDNzLTMtMS0zLTN6IiBmaWxsPSIjZmZmIi8+PC9zdmc+");
@@ -205,6 +215,12 @@ pre:has(code) {
     &.icon-rkgk-grayscale {
         background-image: var(--icon-rkgk-grayscale);
     }
+    &.icon-plus {
+        background-image: var(--icon-plus);
+    }
+    &.icon-minus {
+        background-image: var(--icon-minus);
+    }
 
     &.icon-brackets-white {
         background-image: var(--icon-brackets-white);
diff --git a/static/icon/minus.svg b/static/icon/minus.svg
new file mode 100644
index 0000000..b4d68a1
--- /dev/null
+++ b/static/icon/minus.svg
@@ -0,0 +1,3 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<rect x="4" y="7" width="8" height="2" fill="black"/>
+</svg>
diff --git a/static/icon/plus.svg b/static/icon/plus.svg
new file mode 100644
index 0000000..225e980
--- /dev/null
+++ b/static/icon/plus.svg
@@ -0,0 +1,4 @@
+<svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
+<rect x="7" y="4" width="2" height="8" fill="black"/>
+<rect x="4" y="7" width="8" height="2" fill="black"/>
+</svg>
diff --git a/static/index.css b/static/index.css
index 0c5fddb..eb3c060 100644
--- a/static/index.css
+++ b/static/index.css
@@ -54,6 +54,21 @@ main {
             pointer-events: all;
         }
 
+        & > .left {
+            display: flex;
+            flex-direction: column;
+
+            pointer-events: none;
+
+            & > * {
+                pointer-events: auto;
+            }
+
+            & > rkgk-zoom-indicator {
+                margin-block-start: auto;
+            }
+        }
+
         & > .right {
             grid-column: right / right;
             min-height: 0;
@@ -439,6 +454,38 @@ rkgk-brush-cost-gauges.rkgk-panel {
     }
 }
 
+/* Zoom indicator */
+
+rkgk-zoom-indicator,
+rkgk-zoom-indicator.rkgk-panel {
+    border-radius: 4px;
+
+    display: flex;
+    flex-direction: row;
+    align-items: center;
+
+    width: min-content;
+
+    overflow: clip; /* corners */
+
+    & > button {
+        width: 24px;
+        height: 24px;
+    }
+
+    & > p {
+        margin: 0;
+        padding: 0 4px;
+        line-height: 1;
+        width: 6ch;
+
+        user-select: none;
+
+        font-variant-numeric: tabular-nums;
+        text-align: center;
+    }
+}
+
 /* Welcome screen */
 
 rkgk-welcome {
diff --git a/static/index.js b/static/index.js
index 58ac40e..0329cb6 100644
--- a/static/index.js
+++ b/static/index.js
@@ -19,6 +19,7 @@ let reticleRenderer = main.querySelector("rkgk-reticle-renderer");
 let brushEditor = main.querySelector("rkgk-brush-editor");
 let brushPreview = main.querySelector("rkgk-brush-preview");
 let brushCostGauges = main.querySelector("rkgk-brush-cost-gauges");
+let zoomIndicator = main.querySelector("rkgk-zoom-indicator");
 let welcome = main.querySelector("rkgk-welcome");
 let connectionStatus = main.querySelector("rkgk-connection-status");
 
@@ -62,6 +63,8 @@ function readUrl(urlString) {
 
 // In the background, connect to the server.
 (async () => {
+    // Initialization
+
     console.info("checking for user registration status");
     if (!isUserLoggedIn()) {
         await welcome.show({
@@ -79,6 +82,7 @@ function readUrl(urlString) {
     canvasRenderer.viewport.panX = urlData.viewport.x;
     canvasRenderer.viewport.panY = urlData.viewport.y;
     canvasRenderer.viewport.zoomLevel = urlData.viewport.zoom;
+    zoomIndicator.setZoom(canvasRenderer.viewport.zoom);
 
     let session = await newSession({
         userId: getUserId(),
@@ -124,6 +128,7 @@ function readUrl(urlString) {
             canvasRenderer.viewport.panX = newUrlData.viewport.x;
             canvasRenderer.viewport.panY = newUrlData.viewport.y;
             canvasRenderer.viewport.zoomLevel = newUrlData.viewport.zoom;
+            zoomIndicator.setZoom(canvasRenderer.viewport.zoom);
             canvasRenderer.sendViewportUpdate();
         }
     });
@@ -140,6 +145,8 @@ function readUrl(urlString) {
 
     let currentUser = wall.onlineUsers.getUser(session.sessionId);
 
+    // Event loop
+
     session.addEventListener("error", (event) => console.error(event));
 
     session.addEventListener("wallEvent", (event) => {
@@ -248,6 +255,8 @@ function readUrl(urlString) {
         updateUrl(session, canvasRenderer.viewport),
     );
 
+    // Brush editor
+
     function compileBrush() {
         let compileResult = currentUser.setBrush(brushEditor.code);
         brushEditor.renderHakuResult("Compilation", compileResult);
@@ -279,5 +288,17 @@ function readUrl(urlString) {
         });
     });
 
+    // Zoom indicator
+
+    canvasRenderer.addEventListener(".viewportUpdate", () => {
+        zoomIndicator.setZoom(canvasRenderer.viewport.zoom);
+    });
+    zoomIndicator.addEventListener(".zoomUpdate", (event) => {
+        canvasRenderer.viewport.zoomLevel += event.delta;
+        canvasRenderer.sendViewportUpdate();
+    });
+
+    // All done.
+
     session.eventLoop();
 })();
diff --git a/static/zoom-indicator.js b/static/zoom-indicator.js
new file mode 100644
index 0000000..76df44f
--- /dev/null
+++ b/static/zoom-indicator.js
@@ -0,0 +1,25 @@
+class ZoomIndicator extends HTMLElement {
+    connectedCallback() {
+        this.zoomOutButton = this.appendChild(document.createElement("button"));
+        this.zoomOutButton.classList.add("icon", "icon-minus");
+
+        this.zoomLevelText = this.appendChild(document.createElement("p"));
+        this.zoomLevelText.innerText = "100%";
+
+        this.zoomInButton = this.appendChild(document.createElement("button"));
+        this.zoomInButton.classList.add("icon", "icon-plus");
+
+        this.zoomInButton.addEventListener("click", () => {
+            this.dispatchEvent(Object.assign(new Event(".zoomUpdate"), { delta: +1 }));
+        });
+        this.zoomOutButton.addEventListener("click", () => {
+            this.dispatchEvent(Object.assign(new Event(".zoomUpdate"), { delta: -1 }));
+        });
+    }
+
+    setZoom(value) {
+        this.zoomLevelText.innerText = `${Math.round(value * 100)}%`;
+    }
+}
+
+customElements.define("rkgk-zoom-indicator", ZoomIndicator);
diff --git a/template/index.hbs.html b/template/index.hbs.html
index f9d846a..dbac156 100644
--- a/template/index.hbs.html
+++ b/template/index.hbs.html
@@ -18,7 +18,7 @@
             const HAKU_WASM_PATH = "{{{ static 'wasm/haku.wasm' }}}";
         </script>
         
-        <script type="module">
+        <script type="module" async>
             import "rkgk/live-reload.js";
 
             import "rkgk/brush-cost.js";
@@ -33,6 +33,7 @@
             import "rkgk/throbber.js";
             import "rkgk/viewport.js";
             import "rkgk/welcome.js";
+            import "rkgk/zoom-indicator.js";
     
             import "rkgk/index.js";
         </script>
@@ -56,10 +57,14 @@
             <rkgk-canvas-renderer class="fullscreen"></rkgk-canvas-renderer>
             <rkgk-reticle-renderer class="fullscreen"></rkgk-reticle-renderer>
             <div class="panels fullscreen" id="panels-overlay">
-                <div class="rkgk-panel menu-bar">
-                    <a class="icon icon-rkgk-grayscale" title="I know this menu bar is really ugly. Sorry about that."></a>
-                    <hr>
-                    <a href="/docs/rkgk.html">Manual</a>
+                <div class="left">
+                    <div class="rkgk-panel menu-bar">
+                        <a class="icon icon-rkgk-grayscale" title="I know this menu bar is really ugly. Sorry about that."></a>
+                        <hr>
+                        <a href="/docs/rkgk.html">Manual</a>
+                    </div>
+
+                    <rkgk-zoom-indicator class="rkgk-panel"></rkgk-zoom-indicator>
                 </div>
 
                 <div class="right">