diff --git a/pkg/bytefmt/bytefmt.go b/pkg/bytefmt/bytefmt.go
index a56f82f0c..2b8f63478 100644
--- a/pkg/bytefmt/bytefmt.go
+++ b/pkg/bytefmt/bytefmt.go
@@ -87,6 +87,15 @@ func ToKilobytes(s string) (uint64, error) {
 
 // ToBytes parses a string formatted by ByteSize as bytes.
 func ToBytes(s string) (uint64, error) {
+	l := len(s)
+	if l < 1 {
+		return 0, ErrorInvalidByte
+	}
+
+	if s[l-1] != 'b' && s[l-1] != 'B' {
+		s = s + "B"
+	}
+
 	parts := bytesPattern.FindStringSubmatch(strings.TrimSpace(s))
 	if len(parts) < 3 {
 		return 0, ErrorInvalidByte
diff --git a/pkg/bytefmt/bytefmt_test.go b/pkg/bytefmt/bytefmt_test.go
index cd0348f48..29e7cfd12 100644
--- a/pkg/bytefmt/bytefmt_test.go
+++ b/pkg/bytefmt/bytefmt_test.go
@@ -96,6 +96,11 @@ func TestToBytes(t *testing.T) {
 			expect: uint64(10.5 * 1024),
 			err:    nil,
 		},
+		{
+			input:  "1024000",
+			expect: 1024000,
+			err:    nil,
+		},
 	}
 	for _, test := range tests {
 		out, err := ToBytes(test.input)
diff --git a/test/cli_volume_test.go b/test/cli_volume_test.go
index 5e05c2085..ba9b3d45a 100644
--- a/test/cli_volume_test.go
+++ b/test/cli_volume_test.go
@@ -167,6 +167,19 @@ func (suite *PouchVolumeSuite) TestVolumeCreateWithSelector(c *check.C) {
 	command.PouchRun("volume", "remove", funcname)
 }
 
+// TestVolumeCreateWithSize tests creating volume with -o size=xxx.
+func (suite *PouchVolumeSuite) TestVolumeCreateWithSize(c *check.C) {
+	pc, _, _, _ := runtime.Caller(0)
+	tmpname := strings.Split(runtime.FuncForPC(pc).Name(), ".")
+	var funcname string
+	for i := range tmpname {
+		funcname = tmpname[i]
+	}
+
+	command.PouchRun("volume", "create", "--name", funcname, "-o", "size=1048576").Assert(c, icmd.Success)
+	command.PouchRun("volume", "remove", funcname)
+}
+
 // TestVolumeInspectFormat tests the inspect format of volume works.
 func (suite *PouchVolumeSuite) TestVolumeInspectFormat(c *check.C) {
 	pc, _, _, _ := runtime.Caller(0)