diff --git a/serialize.go b/serialize.go
index 90d5444..b14e3a0 100644
--- a/serialize.go
+++ b/serialize.go
@@ -42,13 +42,30 @@ func (cr CronRange) String() string {
 	return sb.String()
 }
 
+// ParseOpt Specifies an interface for parser opts
+type ParseOpt interface{}
+
+// DefaultDuration provides a fallback duration if the cron doesn't specify one. Duration must be 1 minute or greater
+type DefaultDuration time.Duration
+
 // ParseString attempts to deserialize the given expression or return failure if any parsing errors occur.
-func ParseString(s string) (cr *CronRange, err error) {
+// ParseOpts can include: DefaultDuration(1 * time.Minute) to set a duration. Must be greater than 1 minute. Units smaller
+// than a minute are truncated. using uint64 type conversation from duration.
+func ParseString(s string, opts ...ParseOpt) (cr *CronRange, err error) {
 	if s == "" {
 		err = errEmptyExpr
 		return
 	}
 
+	var defaultDuration *time.Duration = nil
+
+	for _, opt := range opts {
+		if opt, ok := opt.(DefaultDuration); ok {
+			duration := time.Duration(opt)
+			defaultDuration = &duration
+		}
+	}
+
 	var (
 		cronExpr, timeZone, durStr string
 		durMin                     uint64
@@ -87,6 +104,8 @@ PL:
 	if err == nil {
 		if len(durStr) > 0 {
 			cr, err = New(cronExpr, timeZone, durMin)
+		} else if defaultDuration != nil {
+			cr, err = New(cronExpr, timeZone, uint64(*defaultDuration/time.Minute))
 		} else {
 			err = errMissDurationExpr
 		}
diff --git a/serialize_test.go b/serialize_test.go
index 061cafb..7939090 100644
--- a/serialize_test.go
+++ b/serialize_test.go
@@ -53,35 +53,45 @@ func BenchmarkCronRange_String(b *testing.B) {
 }
 
 var deserializeTestCases = []struct {
-	name    string
-	inputS  string
-	wantS   string
-	wantErr bool
+	name      string
+	inputS    string
+	wantS     string
+	wantErr   bool
+	inputOpts []ParseOpt
 }{
-	{"Empty string", emptyString, emptyString, true},
-	{"Invalid expression", "hello", emptyString, true},
-	{"Missing duration", "; * * * * *", emptyString, true},
-	{"Invalid duration=0", "DR=0;* * * * *", emptyString, true},
-	{"Invalid duration=-5", "DR=-5;* * * * *", emptyString, true},
-	{"Invalid with Mars time zone", "DR=5;TZ=Mars;* * * * *", emptyString, true},
-	{"Invalid with unknown part", "DR=10; TZ=Pacific/Honolulu; SET=1; * * * * *", emptyString, true},
-	{"Invalid with lower case", "dr=5;* * * * *", emptyString, true},
-	{"Invalid with wrong order", "* * * * *; DR=5;", emptyString, true},
-	{"Normal without timezone", "DR=5;* * * * *", "DR=5; * * * * *", false},
-	{"Normal with extra whitespaces", "  DR=6 ;  * * * * *  ", "DR=6; * * * * *", false},
-	{"Normal with empty parts", ";  DR=7;;; ;; ;; ;* * * * *  ", "DR=7; * * * * *", false},
-	{"Normal with different order", "TZ=Asia/Tokyo;  DR=1440;  0 0 1 1 *", "DR=1440; TZ=Asia/Tokyo; 0 0 1 1 *", false},
-	{"Normal with local time zone", "DR=8;TZ=Local;* * * * *", "DR=8; * * * * *", false},
-	{"Normal with UTC time zone", "DR=9;TZ=Etc/UTC;* * * * *", "DR=9; TZ=Etc/UTC; * * * * *", false},
-	{"Normal with Honolulu time zone", "DR=10;TZ=Pacific/Honolulu;* * * * *", "DR=10; TZ=Pacific/Honolulu; * * * * *", false},
-	{"Normal with Honolulu time zone in different order", "TZ=Pacific/Honolulu; DR=10; * * * * *", "DR=10; TZ=Pacific/Honolulu; * * * * *", false},
-	{"Normal with complicated expression", "DR=5258765;   TZ=Pacific/Honolulu;   4,8,22,27,33,38,47,50 3,11,14-16,19,21,22 */10 1,3,5,6,9-11 1-5", "DR=5258765; TZ=Pacific/Honolulu; 4,8,22,27,33,38,47,50 3,11,14-16,19,21,22 */10 1,3,5,6,9-11 1-5", false},
+	{"Empty string", emptyString, emptyString, true, nil},
+	{"Invalid expression", "hello", emptyString, true, nil},
+	{"Missing duration", "; * * * * *", emptyString, true, nil},
+	{"Missing duration default takes priority", "; * * * * *", "DR=1; * * * * *", false, []ParseOpt{DefaultDuration(1 * time.Minute)}},
+	{"Missing duration default takes priority fails if invalid", "; * * * * *", emptyString, true, []ParseOpt{DefaultDuration(0 * time.Minute)}},
+	{"Invalid duration=0", "DR=0;* * * * *", emptyString, true, nil},
+	{"Invalid duration=0 default duration doesn't impact invalid durations", "DR=0;* * * * *", emptyString, true, []ParseOpt{DefaultDuration(1 * time.Minute)}},
+	{"Invalid duration=-5", "DR=-5;* * * * *", emptyString, true, nil},
+	{"Invalid duration=-5 default doesn't override", "DR=-5;* * * * *", emptyString, true, []ParseOpt{DefaultDuration(1 * time.Minute)}},
+	{"Invalid with Mars time zone", "DR=5;TZ=Mars;* * * * *", emptyString, true, nil},
+	{"Invalid with unknown part", "DR=10; TZ=Pacific/Honolulu; SET=1; * * * * *", emptyString, true, nil},
+	{"Invalid with lower case", "dr=5;* * * * *", emptyString, true, nil},
+	{"Invalid with lower case default duration overrides", "dr=5;* * * * *", "DR=1; * * * * *", true, []ParseOpt{DefaultDuration(1 * time.Minute)}},
+	{"Invalid with wrong order", "* * * * *; DR=5;", emptyString, true, nil},
+	{"Invalid with wrong order fails even with default duration", "* * * * *; DR=5;", emptyString, true, []ParseOpt{DefaultDuration(1 * time.Minute)}},
+	{"Normal without timezone", "DR=5;* * * * *", "DR=5; * * * * *", false, nil},
+	{"Normal with extra whitespaces", "  DR=6 ;  * * * * *  ", "DR=6; * * * * *", false, nil},
+	{"Normal with double duration", "DR=6;DR=7; * * * * *  ", "DR=7; * * * * *", false, nil},
+	{"Normal with empty parts", ";  DR=7;;; ;; ;; ;* * * * *  ", "DR=7; * * * * *", false, nil},
+	{"Normal with different order", "TZ=Asia/Tokyo;  DR=1440;  0 0 1 1 *", "DR=1440; TZ=Asia/Tokyo; 0 0 1 1 *", false, nil},
+	{"Normal with local time zone", "DR=8;TZ=Local;* * * * *", "DR=8; * * * * *", false, nil},
+	{"Normal with UTC time zone", "DR=9;TZ=Etc/UTC;* * * * *", "DR=9; TZ=Etc/UTC; * * * * *", false, nil},
+	{"Normal with local time zone default duration works with tz", "TZ=Local;* * * * *", "DR=1; * * * * *", false, []ParseOpt{DefaultDuration(1 * time.Minute)}},
+	{"Normal with UTC time zone default duration works with tz", "TZ=Etc/UTC;* * * * *", "DR=1; TZ=Etc/UTC; * * * * *", false, []ParseOpt{DefaultDuration(1 * time.Minute)}},
+	{"Normal with Honolulu time zone", "DR=10;TZ=Pacific/Honolulu;* * * * *", "DR=10; TZ=Pacific/Honolulu; * * * * *", false, nil},
+	{"Normal with Honolulu time zone in different order", "TZ=Pacific/Honolulu; DR=10; * * * * *", "DR=10; TZ=Pacific/Honolulu; * * * * *", false, nil},
+	{"Normal with complicated expression", "DR=5258765;   TZ=Pacific/Honolulu;   4,8,22,27,33,38,47,50 3,11,14-16,19,21,22 */10 1,3,5,6,9-11 1-5", "DR=5258765; TZ=Pacific/Honolulu; 4,8,22,27,33,38,47,50 3,11,14-16,19,21,22 */10 1,3,5,6,9-11 1-5", false, nil},
 }
 
 func TestParseString(t *testing.T) {
 	for _, tt := range deserializeTestCases {
 		t.Run(tt.name, func(t *testing.T) {
-			gotCr, err := ParseString(tt.inputS)
+			gotCr, err := ParseString(tt.inputS, tt.inputOpts...)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("ParseString() error: %v, wantErr: %v", err, tt.wantErr)
 				return