diff --git a/index.js b/index.js
index 3e2b5dc..d05d5c8 100644
--- a/index.js
+++ b/index.js
@@ -33,5 +33,5 @@ export default function parse(str = '', format = 'ms') {
     if (units) result = (result || 0) + n * units
   })
 
-  return result && ((result / (parse.unit[format] || 1)) * (str[0] === '-' ? -1 : 1))
+  return result && ((result / (parse.unit[format] || 1)) * (String(str).trimStart()[0] === '-' ? -1 : 1))
 }
diff --git a/test.js b/test.js
index ed7c11e..422ee3d 100644
--- a/test.js
+++ b/test.js
@@ -97,6 +97,9 @@ t('combined', t => {
 	t.equal(parse('running length: 1hour:20mins'), 1 * h + 20 * m)
 	t.equal(parse('2hr -40mins'), 2 * h + 40 * m)
 	t.equal(parse('-1hr 40mins'), -1 * h - 40 * m)
+	t.equal(parse(' -1hr 40mins'), -1 * h - 40 * m)
+	t.equal(parse('  -1h'), -1 * h)
+	t.equal(parse('\t-30m'), -30 * m)
 	t.equal(parse('2e3s'), 2000 * s)
 	t.end()
 })