diff --git a/src/plugin/customParseFormat/index.js b/src/plugin/customParseFormat/index.js
index 940bb43a..f2eabb2b 100644
--- a/src/plugin/customParseFormat/index.js
+++ b/src/plugin/customParseFormat/index.js
@@ -8,14 +8,15 @@ const match3 = /\d{3}/ // 000 - 999
 const match4 = /\d{4}/ // 0000 - 9999
 const match1to2 = /\d\d?/ // 0 - 99
 const matchSigned = /[+-]?\d+/ // -inf - inf
-const matchOffset = /[+-]\d\d:?\d\d/ // +00:00 -00:00 +0000 or -0000
+const matchOffset = /[+-]\d\d:?(\d\d)?/ // +00:00 -00:00 +0000 or -0000 +00
 const matchWord = /\d*[^\s\d-:/()]+/ // Word
 
 let locale
 
 function offsetFromString(string) {
+  if (!string) return 0
   const parts = string.match(/([+-]|\d\d)/g)
-  const minutes = +(parts[1] * 60) + +parts[2]
+  const minutes = +(parts[1] * 60) + (+parts[2] || 0)
   return minutes === 0 ? 0 : parts[0] === '+' ? -minutes : minutes // eslint-disable-line no-nested-ternary
 }
 
diff --git a/test/plugin/customParseFormat.test.js b/test/plugin/customParseFormat.test.js
index 03b446a6..ef8bfd62 100644
--- a/test/plugin/customParseFormat.test.js
+++ b/test/plugin/customParseFormat.test.js
@@ -101,6 +101,22 @@ it('timezone with no hour', () => {
   expect(dayjs(input, format).valueOf()).toBe(moment(input, format).valueOf())
 })
 
+describe('Timezone Offset', () => {
+  it('timezone with 2-digit offset', () => {
+    const input = '2020-12-01T20:00:00+09'
+    const format = 'YYYY-MM-DD[T]HH:mm:ssZZ'
+    const result = dayjs(input, format)
+    expect(result.valueOf()).toBe(moment(input, format).valueOf())
+    expect(result.valueOf()).toBe(1606820400000)
+  })
+  it('no timezone format token should parse in local time', () => {
+    const input = '2020-12-01T20:00:00+01:00'
+    const format = 'YYYY-MM-DD[T]HH:mm:ss'
+    const result = dayjs(input, format)
+    expect(result.valueOf()).toBe(moment(input, format).valueOf())
+  })
+})
+
 it('parse hh:mm', () => {
   const input = '12:00'
   const format = 'hh:mm'