diff --git a/field/packer_unpacker.go b/field/packer_unpacker.go
index 35408c8..0434cfe 100644
--- a/field/packer_unpacker.go
+++ b/field/packer_unpacker.go
@@ -20,7 +20,7 @@ func (p defaultPacker) Pack(value []byte, spec *Spec) ([]byte, error) {
 	}
 
 	// encode the length
-	lengthPrefix, err := spec.Pref.EncodeLength(spec.Length, len(value))
+	lengthPrefix, err := spec.Pref.EncodeLength(spec.Length, len(encodedValue))
 	if err != nil {
 		return nil, fmt.Errorf("failed to encode length: %w", err)
 	}
@@ -73,7 +73,7 @@ func (p Track2Packer) Pack(value []byte, spec *Spec) ([]byte, error) {
 
 	// Encode the length to that of the original string, not the potentially
 	// padded length
-	packedLength, err := spec.Pref.EncodeLength(spec.Length, len(value))
+	packedLength, err := spec.Pref.EncodeLength(spec.Length, len(packed))
 	if err != nil {
 		return nil, fmt.Errorf("failed to encode length: %w", err)
 	}
diff --git a/field/packer_unpacker_test.go b/field/packer_unpacker_test.go
index 565c8af..762a2b8 100644
--- a/field/packer_unpacker_test.go
+++ b/field/packer_unpacker_test.go
@@ -184,3 +184,25 @@ func TestTrack2Packer(t *testing.T) {
 		})
 	}
 }
+
+func TestPackerandUnpackerWithVariantDataLength(t *testing.T) {
+	spec := &field.Spec{
+		Length:      5,
+		Description: "Field",
+		Enc:         encoding.EBCDIC1047,
+		Pref:        prefix.EBCDIC1047.L,
+	}
+
+	data := []byte{0xc2, 0xa0, 0x31}
+	str := field.NewString(spec)
+	str.SetBytes(data)
+
+	packed, err := str.Pack()
+	require.NoError(t, err)
+
+	_, err = str.Unpack(packed)
+	require.NoError(t, err)
+	bytes, err := str.Bytes()
+	require.NoError(t, err)
+	require.Equal(t, data, bytes)
+}