diff --git a/macrovision.css b/macrovision.css
index 95357089..4d7be3a8 100644
--- a/macrovision.css
+++ b/macrovision.css
@@ -290,6 +290,14 @@ select.menu-item {
     color: #000;
 }
 
+#rulers {
+    position: absolute;
+    display: block;
+    width: 100%;
+    height: 100%;
+    background: #00000000;
+}
+
 #display {
     display: block;
     width: 100%;
@@ -720,6 +728,11 @@ option.filtered {
     top: 60%;
 }
 
+#ruler {
+    left: 0%;
+    top: 80%;
+}
+
 #fit {
     right: 0%;
     top: 80%;
diff --git a/macrovision.html b/macrovision.html
index d50db2ca..b6310792 100644
--- a/macrovision.html
+++ b/macrovision.html
@@ -298,9 +298,14 @@
       <button class="scroll-button" disabled id="grow">
         <i class="fas fa-expand-arrows-alt"></i>
       </button>
+      <button class="scroll-button" id="ruler">
+        <i class="fas fa-ruler"></i>
+      </button>
       <button class="scroll-button" disabled id="fit">
         <i class="fas fa-search"></i>
       </button>
+      <canvas id="rulers">
+      </canvas>
       <div id="entities">
 
       </div>
diff --git a/macrovision.js b/macrovision.js
index 75d16d3d..af56f946 100644
--- a/macrovision.js
+++ b/macrovision.js
@@ -41,6 +41,12 @@ let sizeHandle = null;
 
 let worldSizeDirty = false;
 
+let rulerMode = false;
+
+let rulers = [];
+
+let currentRuler = undefined;
+
 const tagDefs = {
     "anthro": "Anthro",
     "feral": "Feral",
@@ -532,6 +538,50 @@ function updateSizes(dirtyOnly = false) {
     document.querySelector("#ground").style.top = pos2pix({x: 0, y: 0}).y + "px";
 
 
+    drawRulers();
+}
+
+function drawRulers() {
+    const canvas = document.querySelector("#rulers");
+
+    /** @type {CanvasRenderingContext2D} */
+
+    const ctx = canvas.getContext("2d");
+    ctx.canvas.width = canvas.clientWidth;
+    ctx.canvas.height = canvas.clientHeight;
+
+    
+    rulers.concat(currentRuler ? [currentRuler] : []).forEach(rulerDef => {
+        ctx.save();
+        ctx.beginPath();
+        const start = pos2pix({x: rulerDef.x0, y: rulerDef.y0});
+        const end = pos2pix({x: rulerDef.x1, y: rulerDef.y1});
+        ctx.moveTo(start.x, start.y);
+        ctx.lineTo(end.x, end.y);
+        ctx.lineWidth = 5;
+        ctx.stroke();
+        const center = { x: (start.x + end.x) / 2, y: (start.y + end.y) / 2 };
+        ctx.fillStyle = "#eeeeee";
+        ctx.font = 'normal 24pt coda';
+        ctx.translate(center.x, center.y);
+        let angle = Math.atan2(end.y - start.y, end.x - start.x);
+
+        if (angle < -Math.PI/2) {
+            angle += Math.PI;
+        }
+        if (angle > Math.PI/2) {
+            angle -= Math.PI;
+        }
+        ctx.rotate(angle);
+        const offsetX = Math.cos(angle + Math.PI/2);
+        const offsetY = Math.sin(angle + Math.PI/2);
+        
+        const distance = Math.sqrt(Math.pow(rulerDef.y1 - rulerDef.y0, 2) + Math.pow(rulerDef.x1 - rulerDef.x0, 2));
+        const distanceInUnits = math.unit(distance, "meters").to(document.querySelector("#options-height-unit").value);
+        const textSize = ctx.measureText(distanceInUnits.format({ precision: 3}));
+        ctx.fillText(distanceInUnits.format({ precision: 3}), -offsetX * 10 - textSize.width / 2, -offsetY*10);
+        ctx.restore();
+    });
 }
 
 function drawScales(ifDirty = false) {
@@ -1855,6 +1905,11 @@ function prepareSidebar() {
             name: "Add Image",
             id: "menu-add-image",
             icon: "fas fa-camera"
+        },
+        {
+            name: "Clear Rulers",
+            id: "menu-clear-rulers",
+            icon: "fas fa-ruler"
         }
     ].forEach(entry => {
         const buttonHolder = document.createElement("div");
@@ -2582,13 +2637,15 @@ document.addEventListener("DOMContentLoaded", () => {
     });
 
     document.querySelector("#world").addEventListener("touchstart", e => {
-        panning = true;
-        panOffsetX = e.touches[0].clientX;
-        panOffsetY = e.touches[0].clientY;
-        e.preventDefault();
-        Object.keys(entities).forEach(key => {
-            document.querySelector("#entity-" + key).classList.add("no-transition");
-        });
+        if (!rulerMode) {
+            panning = true;
+            panOffsetX = e.touches[0].clientX;
+            panOffsetY = e.touches[0].clientY;
+            e.preventDefault();
+            Object.keys(entities).forEach(key => {
+                document.querySelector("#entity-" + key).classList.add("no-transition");
+            });
+        }
     });
 
     document.querySelector("#world").addEventListener("touchend", e => {
@@ -2597,6 +2654,39 @@ document.addEventListener("DOMContentLoaded", () => {
             document.querySelector("#entity-" + key).classList.remove("no-transition");
         });
     });
+    document.querySelector("#world").addEventListener("mousedown", e => {
+        // only left mouse clicks
+        if (e.which == 1 && rulerMode) {
+            let entX = document.querySelector("#entities").getBoundingClientRect().x;
+            let entY = document.querySelector("#entities").getBoundingClientRect().y;
+            const pos = pix2pos({ x: e.clientX - entX, y: e.clientY - entY });
+            currentRuler = { x0: pos.x, y0: pos.y, x1: pos.y, y1: pos.y };
+        }
+    });
+    document.querySelector("#world").addEventListener("mouseup", e => {
+        // only left mouse clicks
+        if (e.which == 1 && currentRuler) {
+            rulers.push(currentRuler);
+            currentRuler = null;
+            rulerMode = false;
+        }
+    });
+
+    document.querySelector("#world").addEventListener("touchstart", e => {
+        if (rulerMode) {
+            let entX = document.querySelector("#entities").getBoundingClientRect().x;
+            let entY = document.querySelector("#entities").getBoundingClientRect().y;
+            const pos = pix2pos({ x: e.touches[0].clientX - entX, y: e.touches[0].clientY - entY });
+            currentRuler = { x0: pos.x, y0: pos.y, x1: pos.y, y1: pos.y };
+        }
+    });
+    document.querySelector("#world").addEventListener("touchend", e => {
+        if (currentRuler) {
+            rulers.push(currentRuler);
+            currentRuler = null;
+            rulerMode = false;
+        }
+    });
 
     document.querySelector("body").appendChild(testCtx.canvas);
 
@@ -2821,6 +2911,23 @@ document.addEventListener("DOMContentLoaded", () => {
         sizeHandle = null;
     });
 
+    document.querySelector("#ruler").addEventListener("click", e => {
+        rulerMode = !rulerMode;
+        if (rulerMode) {
+            toast("Ready to draw a ruler mark");
+        } else {
+            toast("Cancelled ruler mode");
+        }
+    });
+
+    document.querySelector("#ruler").addEventListener("mousedown", e => {
+        e.stopPropagation();
+    });
+
+    document.querySelector("#ruler").addEventListener("touchstart", e => {
+        e.stopPropagation();
+    });
+
     document.querySelector("#fit").addEventListener("click", e => {
         if (selected) {
             let targets = {};
@@ -2937,6 +3044,11 @@ document.addEventListener("DOMContentLoaded", () => {
             
     })
 
+    document.querySelector("#menu-clear-rulers").addEventListener("click", e => {
+        rulers = [];
+        drawRulers();
+    });
+
     document.addEventListener("paste", e => {
 
         let index = 0;
@@ -3532,6 +3644,28 @@ function clearFilter() {
     });
 }
 
+document.addEventListener("mousemove", (e) => {
+    if (currentRuler) {
+        let entX = document.querySelector("#entities").getBoundingClientRect().x;
+        let entY = document.querySelector("#entities").getBoundingClientRect().y;
+        let position = pix2pos({ x: e.clientX - entX, y: e.clientY - entY });
+        currentRuler.x1 = position.x;
+        currentRuler.y1 = position.y;
+    }
+    drawRulers();
+});
+
+document.addEventListener("touchmove", (e) => {
+    if (currentRuler) {
+        let entX = document.querySelector("#entities").getBoundingClientRect().x;
+        let entY = document.querySelector("#entities").getBoundingClientRect().y;
+        let position = pix2pos({ x: e.touches[0].clientX - entX, y: e.touches[0].clientY - entY });
+        currentRuler.x1 = position.x;
+        currentRuler.y1 = position.y;
+    }
+    drawRulers();
+});
+
 document.addEventListener("mousemove", (e) => {
     if (clicked) {
         let position = pix2pos({ x: e.clientX - dragOffsetX, y: e.clientY - dragOffsetY });