diff --git a/arbcompress/compress_common.go b/arbcompress/compress_common.go
index 0ce8db079a..a61dd9a171 100644
--- a/arbcompress/compress_common.go
+++ b/arbcompress/compress_common.go
@@ -18,5 +18,5 @@ func compressedBufferSizeFor(length int) int {
 }
 
 func CompressLevel(input []byte, level int) ([]byte, error) {
-	return Compress(input, level, EmptyDictionary)
+	return Compress(input, uint32(level), EmptyDictionary)
 }
diff --git a/arbcompress/native.go b/arbcompress/native.go
index c816019322..4624d6222e 100644
--- a/arbcompress/native.go
+++ b/arbcompress/native.go
@@ -30,7 +30,7 @@ func CompressWell(input []byte) ([]byte, error) {
 	return Compress(input, LEVEL_WELL, EmptyDictionary)
 }
 
-func Compress(input []byte, level int, dictionary Dictionary) ([]byte, error) {
+func Compress(input []byte, level uint32, dictionary Dictionary) ([]byte, error) {
 	maxSize := compressedBufferSizeFor(len(input))
 	output := make([]byte, maxSize)
 	outbuf := sliceToBuffer(output)