diff --git a/calculator/calculator.app.js b/calculator/calculator.app.js
index 5c04ffc..268c81d 100644
--- a/calculator/calculator.app.js
+++ b/calculator/calculator.app.js
@@ -12,7 +12,6 @@ require("FontDylex7x13").add(Graphics);
 
 var DEFAULT_SELECTION_NUMBERS = '5';
 var RESULT_HEIGHT = 40;
-var RESULT_MAX_LEN = Math.floor((g.getWidth() - 20) / 16);
 var COLORS = {
   // [normal, selected]
   DEFAULT: ['#7F8183', '#A6A6A7'],
@@ -218,6 +217,7 @@ function doMath(x, y, operator) {
 function displayOutput(num) {
   g.setBgColor(0).clearRect(0, 0, g.getWidth(), RESULT_HEIGHT-1);
   g.setColor(-1);
+  g.setFont('Dylex7x13', 2);
   if (num === Infinity || num === -Infinity || isNaN(num)) {
     // handle division by 0
     if (num === Infinity) {
@@ -235,7 +235,6 @@ function displayOutput(num) {
     operator = null;
     specials.R.val = 'AC';
     if (!swipeEnabled) drawKey('R', specials.R);
-    g.setFont('Dylex7x13', 2);
   } else {
     // might not be a number due to display of dot "."
     var numNumeric = Number(num);
@@ -253,27 +252,36 @@ function displayOutput(num) {
       }
     }
     var numStr = num.toString();
-    if (typeof num === 'number' && (numStr.length > RESULT_MAX_LEN || (num !== 0 && Math.abs(num) < 1e-4))) {
-        // dynamic precision based on exponent length
-        var exp = Math.floor(Math.log(Math.abs(num)) / Math.LN10);
-        var expLen = String(Math.abs(exp)).length;
-        var signLen = (num < 0) ? 1 : 0;
-        // Total length is sign + first-digit + dot + fraction + E + exp-sign + exp-digits
-        // So precision for fraction is MAX - (sign + first-digit + dot + E + exp-sign + exp-digits)
-        let precision = RESULT_MAX_LEN - (signLen + 1 + 1 + 1 + 1 + expLen);
-        if (precision < 0) precision = 0;
-        num = toExponential(num, precision).replace("e", "E");
-    } else {
-        num = addSeparators(numStr);
+    var displayStr = addSeparators(numStr);
+
+    if (typeof num === 'number' && (g.stringWidth(displayStr) > g.getWidth() - 20 || (num !== 0 && Math.abs(num) < 1e-4))) {
+      // try to format as scientific notation
+      let precision = 10; // start with high precision
+      while (precision >= 0) {
+        let scientificStr = toExponential(num, precision).replace("e", "E");
+        if (g.stringWidth(scientificStr) <= g.getWidth() - 20) {
+          displayStr = scientificStr;
+          break;
+        }
+        precision--;
+      }
+      if (precision < 0) { // if it still doesn't fit
+        displayStr = toExponential(num, 0).replace("e", "E");
+      }
     }
+    num = displayStr;
+
+    // final check for truncation
+    if (g.stringWidth(num) > g.getWidth() - 20) {
+      while(g.stringWidth(num+'...') > g.getWidth() - 20 && num.length > 1) {
+        num = num.slice(0,-1);
+      }
+      num += '...';
+    }
+
     if (num.charAt(0) === '-') {
       num = '- ' + num.substr(1);
     }
-    g.setFont('Dylex7x13', 2);
-    if (num.length > RESULT_MAX_LEN) {
-      if (num.indexOf("E") < 0)
-        num = num.substr(0, RESULT_MAX_LEN - 1)+'...';
-    }
   }
   g.setFontAlign(1,0);
   g.drawString(num, g.getWidth()-20, RESULT_HEIGHT/2);