diff --git a/code39/encoder.go b/code39/encoder.go
index b1feeec..7177cf1 100644
--- a/code39/encoder.go
+++ b/code39/encoder.go
@@ -3,7 +3,6 @@ package code39
 
 import (
 	"errors"
-	"strconv"
 	"strings"
 
 	"github.com/boombuler/barcode"
@@ -75,12 +74,12 @@ var extendedTable = map[rune]string{
 	127: `%T`,
 }
 
-func getChecksum(content string) string {
+func getChecksum(content string) rune {
 	sum := 0
 	for _, r := range content {
 		info, ok := encodeTable[r]
 		if !ok || info.value < 0 {
-			return "#"
+			return 0
 		}
 
 		sum += info.value
@@ -89,10 +88,10 @@ func getChecksum(content string) string {
 	sum = sum % 43
 	for r, v := range encodeTable {
 		if v.value == sum {
-			return string(r)
+			return r
 		}
 	}
-	return "#"
+	return 0
 }
 
 func prepare(content string) (string, error) {
@@ -124,9 +123,10 @@ func EncodeWithColor(content string, includeChecksum bool, fullASCIIMode bool, c
 		return nil, errors.New("invalid data! try full ascii mode")
 	}
 
+	checkChar := getChecksum(content)
 	data := "*" + content
 	if includeChecksum {
-		data += getChecksum(content)
+		data += string(checkChar)
 	}
 	data += "*"
 
@@ -144,11 +144,8 @@ func EncodeWithColor(content string, includeChecksum bool, fullASCIIMode bool, c
 		result.AddBit(info.data...)
 	}
 
-	checkSum, err := strconv.ParseInt(getChecksum(content), 10, 64)
-	if err != nil {
-		checkSum = 0
-	}
-	return utils.New1DCodeIntCheckSumWithColor(barcode.TypeCode39, content, result, int(checkSum), color), nil
+	checkSum := encodeTable[checkChar].value
+	return utils.New1DCodeIntCheckSumWithColor(barcode.TypeCode39, content, result, checkSum, color), nil
 }
 
 // Encode returns a code39 barcode for the given content
diff --git a/code39/encoder_test.go b/code39/encoder_test.go
index b9a49ea..9437e69 100644
--- a/code39/encoder_test.go
+++ b/code39/encoder_test.go
@@ -20,6 +20,24 @@ func doTest(t *testing.T, addCS, fullASCII bool, data, testResult string) {
 	}
 }
 
+func Test_ChecksumValue(t *testing.T) {
+	letter, err := Encode("A", true, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if letter.CheckSum() != 10 {
+		t.Errorf("Encode(A) checksum = %d, want 10", letter.CheckSum())
+	}
+
+	digit, err := Encode("1", false, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if digit.CheckSum() != 1 {
+		t.Errorf("Encode(1) checksum = %d, want 1", digit.CheckSum())
+	}
+}
+
 func Test_Encode(t *testing.T) {
 	doTest(t, false, false, "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789",
 		"1001011011010110101001011010110100101101101101001010101011001011011010110010101"+