diff --git a/README.md b/README.md
index 17a8a48..6d82c79 100644
--- a/README.md
+++ b/README.md
@@ -42,9 +42,9 @@ https://badgen.now.sh/
 `npm run bench` on my iMac5K(Late 2014), 3.5G i5, with Node.js 10.5.0:
 
 ```bash
-generate by short params x 717,411 ops/sec ±0.79% (89 runs sampled)
-generate by long params  x 692,485 ops/sec ±0.87% (93 runs sampled)
-generate by full params  x 613,054 ops/sec ±0.97% (92 runs sampled)
+generate by short params x 806,080 ops/sec ±0.98% (88 runs sampled)
+generate by long params  x 735,925 ops/sec ±0.85% (90 runs sampled)
+generate by full params  x 770,180 ops/sec ±0.75% (90 runs sampled)
 ```
 
 ## License
diff --git a/bench/index.js b/bench/index.js
index 5aba683..b630aa7 100644
--- a/bench/index.js
+++ b/bench/index.js
@@ -1,9 +1,9 @@
 const { Suite } = require('benchmark')
 const badgen = require('..')
 
-const shortParams = { subject: 'b', status: 'p' }
+const shortParams = { subject: '1', status: '2' }
 const longParams = { subject: 'build-build-build', status: 'passing-passing-passing' }
-const fullParams = { subject: 'license', status: 'Apache-2.0', color: 'blue' }
+const fullParams = { subject: 'license', status: 'MIT', color: 'cyan' }
 
 new Suite()
   .add('generate by short params', () => badgen(shortParams))
diff --git a/lib/calc-text-width.js b/lib/calc-text-width.js
index bba704c..4499526 100644
--- a/lib/calc-text-width.js
+++ b/lib/calc-text-width.js
@@ -5,7 +5,9 @@ const Tahoma12Widths = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
 const Verdana12Widths = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,4.21875,4.72265625,5.5078125,9.8203125,7.62890625,12.9140625,8.71875,3.22265625,5.44921875,5.44921875,7.62890625,9.8203125,4.365234375,5.44921875,4.365234375,5.44921875,7.62890625,7.62890625,7.62890625,7.62890625,7.62890625,7.62890625,7.62890625,7.62890625,7.62890625,7.62890625,5.44921875,5.44921875,9.8203125,9.8203125,9.8203125,6.544921875,12,8.203125,8.2265625,8.37890625,9.24609375,7.587890625,6.896484375,9.3046875,9.017578125,5.05078125,5.455078125,8.314453125,6.6796875,10.11328125,8.9765625,9.4453125,7.236328125,9.4453125,8.34375,8.203125,7.39453125,8.783203125,8.203125,11.865234375,8.220703125,7.3828125,8.220703125,5.44921875,5.44921875,5.44921875,9.8203125,7.62890625,7.62890625,7.20703125,7.4765625,6.251953125,7.4765625,7.1484375,4.21875,7.4765625,7.59375,3.29296875,4.130859375,7.1015625,3.29296875,11.671875,7.59375,7.283203125,7.4765625,7.4765625,5.12109375,6.251953125,4.728515625,7.59375,7.1015625,9.8203125,7.1015625,7.1015625,6.3046875,7.6171875,5.44921875,7.6171875,9.8203125]
 
 function calcWidth (charWidthTable) {
-  const widthTable = charWidthTable.map(w => w + 0.4) // Add letter-spacing
+  const SHIFT = 10
+  const LETTER_SPACING = 0.4 * SHIFT
+  const widthTable = charWidthTable.map(w => Math.round(w * SHIFT + LETTER_SPACING))
   return function (text) {
     if (typeof text !== 'string') {
       return 0
@@ -17,7 +19,7 @@ function calcWidth (charWidthTable) {
         charCode = text[i].charCodeAt()
         total += widthTable[charCode < 127 ? charCode : 64] // "@" for overflows
       }
-      return total
+      return total / SHIFT
     }
   }
 }