diff --git a/src/kiri/client.js b/src/kiri/client.js
index 28eea92c..77690378 100644
--- a/src/kiri/client.js
+++ b/src/kiri/client.js
@@ -209,7 +209,7 @@ KIRI.work = {
                 update(reply.progress, reply.message, reply.layer);
             }
             if (reply.done) {
-                done(reply.output, reply.maxSpeed);
+                done(reply.output, reply.maxSpeed, reply.minSpeed);
             }
             if (reply.error) {
                 done(reply);
@@ -260,7 +260,7 @@ KIRI.work = {
                 progress(reply.progress);
             }
             if (reply.parsed) {
-                done(KIRI.codec.decode(reply.parsed), reply.maxSpeed);
+                done(KIRI.codec.decode(reply.parsed), reply.maxSpeed, reply.minSpeed);
             }
         });
     },
diff --git a/src/kiri/main.js b/src/kiri/main.js
index 5e59b7e4..f4dee3cf 100644
--- a/src/kiri/main.js
+++ b/src/kiri/main.js
@@ -953,7 +953,7 @@
         UI.speeds.style.display = 'none';
     }
 
-    function updateSpeeds(maxSpeed) {
+    function updateSpeeds(maxSpeed, minSpeed) {
         UI.speeds.style.display =
             settings.mode !== 'SLA' &&
             settings.mode !== 'LASER' &&
@@ -977,7 +977,7 @@
                 });
                 UI.speedbar.innerHTML = list.join('');
             });
-            API.event.emit('preview.maxspeed', maxSpeed);
+            API.event.emit('preview.speeds', {min: minSpeed, max: maxSpeed});
         }
     }
 
@@ -1177,7 +1177,7 @@
                 startTime = mark;
             }
             API.show.progress(offset + progress * scale, message);
-        }, function (reply, maxSpeed) {
+        }, function (reply, maxSpeed, minSpeed) {
             // handle worker errors
             if (reply && reply.error) {
                 alert2(reply.error, 5);
@@ -1224,7 +1224,7 @@
             SPACE.update();
             updateSliderMax(true);
             setVisibleLayer(-1, 0);
-            updateSpeeds(maxSpeed);
+            updateSpeeds(maxSpeed, minSpeed);
             updateStackLabelState();
 
             // mark preview complete for export
@@ -1267,13 +1267,13 @@
         setOpacity(0);
         KIRI.client.parse({code, type, settings}, progress => {
             API.show.progress(progress, "parsing");
-        }, (layers, maxSpeed) => {
+        }, (layers, maxSpeed, minSpeed) => {
             API.show.progress(0);
             STACKS.clear();
             const stack = STACKS.create('parse', SPACE.platform.world);
             layers.forEach(layer => stack.add(layer));
             updateSliderMax(true);
-            updateSpeeds(maxSpeed);
+            updateSpeeds(maxSpeed, minSpeed);
             showSlices();
             updateStackLabelState();
             SPACE.update();
diff --git a/src/kiri/print.js b/src/kiri/print.js
index 29c73a9f..a159d398 100644
--- a/src/kiri/print.js
+++ b/src/kiri/print.js
@@ -131,6 +131,7 @@
             height = 0,
             factor = 1,
             tool = 0,
+            minf = Infinity,
             maxf = 0,
             seq = [],
             autolayer = true,
@@ -252,6 +253,7 @@
             if (!moving && point.z) bounds.max.z = Math.max(bounds.max.z, point.z);
 
             // update max speed
+            if (pos.F) minf = Math.min(minf, pos.F);
             maxf = Math.max(maxf, pos.F);
 
             // always add moves to the current sequence
@@ -392,6 +394,7 @@
         scope.imported = gcode;
         scope.lines = lines.length;
         scope.bytes = gcode.length;
+        scope.minSpeed = Math.floor(minf / 60);
         scope.maxSpeed = Math.floor(maxf / 60);
         scope.belt = belt;
 
diff --git a/src/kiri/worker.js b/src/kiri/worker.js
index f5703c91..d703b245 100644
--- a/src/kiri/worker.js
+++ b/src/kiri/worker.js
@@ -220,6 +220,7 @@ KIRI.worker = {
 
         const unitScale = settings.controller.units === 'in' ? (1 / 25.4) : 1;
         const print = current.print || {};
+        const minSpeed = (print.minSpeed || 0) * unitScale;
         const maxSpeed = (print.maxSpeed || 0) * unitScale;
         const state = { zeros: [] };
 
@@ -228,6 +229,7 @@ KIRI.worker = {
         send.done({
             done: true,
             // output: KIRI.codec.encode(layers, state),
+            minSpeed,
             maxSpeed
         }, state.zeros);
     },
@@ -282,11 +284,12 @@ KIRI.worker = {
         const parsed = print.parseGCode(code, offset, progress => {
             send.data({ progress: progress * 0.25 });
         }, done => {
+            const minSpeed = print.minSpeed;
             const maxSpeed = print.maxSpeed;
             const layers = KIRI.driver.FDM.prepareRender(done.output, progress => {
                 send.data({ progress: 0.25 + progress * 0.75 });
             }, { thin: thin || print.belt, flat, tools });
-            send.done({parsed: KIRI.codec.encode(layers), maxSpeed});
+            send.done({parsed: KIRI.codec.encode(layers), maxSpeed, minSpeed});
         }, {
             fdm: mode === 'FDM',
             belt: device.bedBelt
diff --git a/src/mode/fdm/prepare.js b/src/mode/fdm/prepare.js
index 8c9efa8a..0e9af91f 100644
--- a/src/mode/fdm/prepare.js
+++ b/src/mode/fdm/prepare.js
@@ -629,12 +629,25 @@
             opacity: flat ? 0.5 : 1
         };
 
-        const maxspd = levels.map(level => {
-            return level.map(o => o.speed || 0).reduce((a, v) => Math.max(a,v));
-        }).reduce((a, v) => Math.max(a, v)) + 1;
+        let minspd = Infinity;
+        let maxspd = 0;
+
+        for (let level of levels) {
+            for (let o of level) {
+                if (o.speed) {
+                    minspd = Math.min(minspd, o.speed);
+                    maxspd = Math.max(maxspd, o.speed);
+                }
+            }
+        }
+
+        // const maxspd = levels.map(level => {
+        //     return level.map(o => o.speed || 0).reduce((a, v) => Math.max(a,v));
+        // }).reduce((a, v) => Math.max(a, v)) + 1;
 
         // for reporting
-        self.worker.print.maxSpeed = maxspd - 1;
+        self.worker.print.minSpeed = minspd;
+        self.worker.print.maxSpeed = maxspd;
         self.worker.print.thinColor = thin;
         self.worker.print.flatColor = flat;