diff --git a/iguana/segwit_addr.c b/iguana/segwit_addr.c
index 6fba18d09..b371b23c1 100644
--- a/iguana/segwit_addr.c
+++ b/iguana/segwit_addr.c
@@ -108,7 +108,7 @@ int bech32_encode(char *output, const char *hrp, const uint8_t *data, size_t dat
     }
     chk ^= 1;
     for (i = 0; i < chklen; ++i) {
-        *(output++) = charset[(chk >> ((5 - i) * 5)) & 0x1f];
+        *(output++) = charset[(chk >> ((checklen - 1 - i) * 5)) & 0x1f];
     }
     *output = 0;
     printf("checksum %llx\n",(long long)chk);