diff --git a/lib/QRCode.js b/lib/QRCode.js
index d2cc578..bddc95e 100644
--- a/lib/QRCode.js
+++ b/lib/QRCode.js
@@ -25,8 +25,8 @@ function renderCanvas(canvas) {
     cells.forEach(function(row, rowIndex) {
         row.forEach(function(column, columnIndex) {
             ctx.fillStyle = column ? bgColor : fgColor;
-            var w = Math.ceil((rowIndex + 1) * cellWidth) - Math.floor(rowIndex * cellWidth);
-            var h = Math.ceil((columnIndex + 1) * cellHeight) - Math.floor(columnIndex * cellHeight);
+            var w = Math.round((rowIndex + 1) * cellWidth) - Math.round(rowIndex * cellWidth);
+            var h = Math.round((columnIndex + 1) * cellHeight) - Math.round(columnIndex * cellHeight);
             ctx.fillRect(Math.round(rowIndex * cellWidth), Math.round(columnIndex * cellHeight), w, h);
         });
     });