diff --git a/armsrc/epa.c b/armsrc/epa.c
index c29ead02f..7d994d756 100644
--- a/armsrc/epa.c
+++ b/armsrc/epa.c
@@ -431,7 +431,7 @@ int EPA_PACE_MSE_Set_AT(pace_version_info_t pace_version_info, uint8_t password)
 // Perform the PACE protocol by replaying given APDUs
 //-----------------------------------------------------------------------------
 void EPA_PACE_Replay(PacketCommandNG *c) {
-    uint32_t timings[sizeof(apdu_lengths_replay) / sizeof(apdu_lengths_replay[0])] = {0};
+    uint32_t timings[ARRAYLEN(apdu_lengths_replay)] = {0};
 
     // if an APDU has been passed, save it
     if (c->oldarg[0] != 0) {
diff --git a/armsrc/hitagS.c b/armsrc/hitagS.c
index 2c8bdb1a2..fc38d10b3 100644
--- a/armsrc/hitagS.c
+++ b/armsrc/hitagS.c
@@ -1930,7 +1930,7 @@ void check_challenges(bool file_given, uint8_t *data) {
             }
             txlen = 64;
 
-            if (u1 >= (sizeof(unlocker) / sizeof(unlocker[0])))
+            if (u1 >= ARRAYLEN(unlocker))
                 bStop = !false;
             for (i = 0; i < 8; i++)
                 tx[i] = unlocker[u1][i];
diff --git a/client/cmdhf14a.c b/client/cmdhf14a.c
index 45f4224e5..5d3ec4965 100644
--- a/client/cmdhf14a.c
+++ b/client/cmdhf14a.c
@@ -650,7 +650,7 @@ static int SelectCard14443_4(bool disconnect, iso14a_card_select_t *card) {
         // get frame length from ATS in data field
         if (resp.oldarg[0] > 1) {
             uint8_t fsci = resp.data.asBytes[1] & 0x0f;
-            if (fsci < sizeof(atsFSC) / sizeof(atsFSC[0]))
+            if (fsci < ARRAYLEN(atsFSC))
                 frameLength = atsFSC[fsci];
         }
     } else {
@@ -658,7 +658,7 @@ static int SelectCard14443_4(bool disconnect, iso14a_card_select_t *card) {
         iso14a_card_select_t *vcard = (iso14a_card_select_t *) resp.data.asBytes;
         if (vcard->ats_len > 1) {
             uint8_t fsci = vcard->ats[1] & 0x0f;
-            if (fsci < sizeof(atsFSC) / sizeof(atsFSC[0]))
+            if (fsci < ARRAYLEN(atsFSC))
                 frameLength = atsFSC[fsci];
         }
 
@@ -1296,7 +1296,7 @@ int infoHF14A(bool verbose, bool do_nack_test) {
                           (tb1 ? "" : " NOT"),
                           (tc1 ? "" : " NOT"),
                           fsci,
-                          fsci < sizeof(atsFSC) / sizeof(atsFSC[0]) ? atsFSC[fsci] : -1
+                          fsci < ARRAYLEN(atsFSC) ? atsFSC[fsci] : -1
                          );
         }
         pos = 2;
diff --git a/client/cmdhf15.c b/client/cmdhf15.c
index a862b6d01..022a941b2 100644
--- a/client/cmdhf15.c
+++ b/client/cmdhf15.c
@@ -1244,7 +1244,7 @@ static int CmdHF15Restore(const char *Cmd) {
         for (int j = 0; j < blocksize; j++)
             snprintf(hex + j * 2, 3, "%02X", buff[j]);
 
-        for (int j = 0; j < sizeof(uid) / sizeof(uid[0]); j++)
+        for (int j = 0; j < ARRAYLEN(uid); j++)
             snprintf(buff + j * 2, 3, "%02X", uid[j]);
 
         //TODO: Addressed mode currently not work
diff --git a/client/crypto/asn1dump.c b/client/crypto/asn1dump.c
index e197749a0..2c720ad04 100644
--- a/client/crypto/asn1dump.c
+++ b/client/crypto/asn1dump.c
@@ -99,7 +99,7 @@ static int asn1_tlv_compare(const void *a, const void *b) {
 }
 
 static const struct asn1_tag *asn1_get_tag(const struct tlv *tlv) {
-    struct asn1_tag *tag = bsearch(tlv, asn1_tags, sizeof(asn1_tags) / sizeof(asn1_tags[0]),
+    struct asn1_tag *tag = bsearch(tlv, asn1_tags, ARRAYLEN(asn1_tags),
                                    sizeof(asn1_tags[0]), asn1_tlv_compare);
 
     return tag ? tag : &asn1_tags[0];