diff --git a/src/bitops.c b/src/bitops.c
index db975e4dfe..7a385812d0 100644
--- a/src/bitops.c
+++ b/src/bitops.c
@@ -784,7 +784,7 @@ void bitopCommand(client *c) {
     addReplyLongLong(c, maxlen); /* Return the output string length in bytes. */
 }
 
-/* BITCOUNT key [start end [BIT|BYTE]] */
+/* BITCOUNT key [start [end [BIT|BYTE]]] */
 void bitcountCommand(client *c) {
     robj *o;
     long long start, end;
@@ -795,9 +795,8 @@ void bitcountCommand(client *c) {
     unsigned char first_byte_neg_mask = 0, last_byte_neg_mask = 0;
 
     /* Parse start/end range if any. */
-    if (c->argc == 4 || c->argc == 5) {
+    if (c->argc == 3 || c->argc == 4 || c->argc == 5) {
         if (getLongLongFromObjectOrReply(c, c->argv[2], &start, NULL) != C_OK) return;
-        if (getLongLongFromObjectOrReply(c, c->argv[3], &end, NULL) != C_OK) return;
         if (c->argc == 5) {
             if (!strcasecmp(c->argv[4]->ptr, "bit"))
                 isbit = 1;
@@ -808,6 +807,11 @@ void bitcountCommand(client *c) {
                 return;
             }
         }
+        if (c->argc >= 4) {
+            if (getLongLongFromObjectOrReply(c,c->argv[3],&end,NULL) != C_OK)
+                return;
+        }
+        
         /* Lookup, check for type. */
         o = lookupKeyRead(c->db, c->argv[1]);
         if (checkType(c, o, OBJ_STRING)) return;
@@ -817,6 +821,8 @@ void bitcountCommand(client *c) {
         /* Make sure we will not overflow */
         serverAssert(totlen <= LLONG_MAX >> 3);
 
+        if (c->argc < 4) end = totlen-1;
+
         /* Convert negative indexes */
         if (start < 0 && end < 0 && start > end) {
             addReply(c, shared.czero);
@@ -921,12 +927,7 @@ void bitposCommand(client *c) {
         long long totlen = strlen;
         serverAssert(totlen <= LLONG_MAX >> 3);
 
-        if (c->argc < 5) {
-            if (isbit)
-                end = (totlen << 3) + 7;
-            else
-                end = totlen - 1;
-        }
+        if (c->argc < 5) end = totlen - 1;
 
         if (isbit) totlen <<= 3;
         /* Convert negative indexes */
diff --git a/src/commands.def b/src/commands.def
index f76e21f2f3..c59cb01dc1 100644
--- a/src/commands.def
+++ b/src/commands.def
@@ -36,6 +36,7 @@ const char *commandGroupStr(int index) {
 /* BITCOUNT history */
 commandHistory BITCOUNT_History[] = {
 {"7.0.0","Added the `BYTE|BIT` option."},
+{"8.0.0","`end` made optional; when called without argument the command reports the last BYTE."},
 };
 #endif
 
@@ -51,23 +52,28 @@ keySpec BITCOUNT_Keyspecs[1] = {
 };
 #endif
 
-/* BITCOUNT range unit argument table */
-struct COMMAND_ARG BITCOUNT_range_unit_Subargs[] = {
+/* BITCOUNT range end_unit_block unit argument table */
+struct COMMAND_ARG BITCOUNT_range_end_unit_block_unit_Subargs[] = {
 {MAKE_ARG("byte",ARG_TYPE_PURE_TOKEN,-1,"BYTE",NULL,NULL,CMD_ARG_NONE,0,NULL)},
 {MAKE_ARG("bit",ARG_TYPE_PURE_TOKEN,-1,"BIT",NULL,NULL,CMD_ARG_NONE,0,NULL)},
 };
 
+/* BITCOUNT range end_unit_block argument table */
+struct COMMAND_ARG BITCOUNT_range_end_unit_block_Subargs[] = {
+{MAKE_ARG("end",ARG_TYPE_INTEGER,-1,NULL,NULL,NULL,CMD_ARG_NONE,0,NULL)},
+{MAKE_ARG("unit",ARG_TYPE_ONEOF,-1,NULL,NULL,"7.0.0",CMD_ARG_OPTIONAL,2,NULL),.subargs=BITCOUNT_range_end_unit_block_unit_Subargs},
+};
+
 /* BITCOUNT range argument table */
 struct COMMAND_ARG BITCOUNT_range_Subargs[] = {
 {MAKE_ARG("start",ARG_TYPE_INTEGER,-1,NULL,NULL,NULL,CMD_ARG_NONE,0,NULL)},
-{MAKE_ARG("end",ARG_TYPE_INTEGER,-1,NULL,NULL,NULL,CMD_ARG_NONE,0,NULL)},
-{MAKE_ARG("unit",ARG_TYPE_ONEOF,-1,NULL,NULL,"7.0.0",CMD_ARG_OPTIONAL,2,NULL),.subargs=BITCOUNT_range_unit_Subargs},
+{MAKE_ARG("end-unit-block",ARG_TYPE_BLOCK,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,2,NULL),.subargs=BITCOUNT_range_end_unit_block_Subargs},
 };
 
 /* BITCOUNT argument table */
 struct COMMAND_ARG BITCOUNT_Args[] = {
 {MAKE_ARG("key",ARG_TYPE_KEY,0,NULL,NULL,NULL,CMD_ARG_NONE,0,NULL)},
-{MAKE_ARG("range",ARG_TYPE_BLOCK,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,3,NULL),.subargs=BITCOUNT_range_Subargs},
+{MAKE_ARG("range",ARG_TYPE_BLOCK,-1,NULL,NULL,NULL,CMD_ARG_OPTIONAL,2,NULL),.subargs=BITCOUNT_range_Subargs},
 };
 
 /********** BITFIELD ********************/
@@ -10661,7 +10667,7 @@ struct COMMAND_ARG WATCH_Args[] = {
 /* Main command table */
 struct COMMAND_STRUCT serverCommandTable[] = {
 /* bitmap */
-{MAKE_CMD("bitcount","Counts the number of set bits (population counting) in a string.","O(N)","2.6.0",CMD_DOC_NONE,NULL,NULL,"bitmap",COMMAND_GROUP_BITMAP,BITCOUNT_History,1,BITCOUNT_Tips,0,bitcountCommand,-2,CMD_READONLY,ACL_CATEGORY_BITMAP,BITCOUNT_Keyspecs,1,NULL,2),.args=BITCOUNT_Args},
+{MAKE_CMD("bitcount","Counts the number of set bits (population counting) in a string.","O(N)","2.6.0",CMD_DOC_NONE,NULL,NULL,"bitmap",COMMAND_GROUP_BITMAP,BITCOUNT_History,2,BITCOUNT_Tips,0,bitcountCommand,-2,CMD_READONLY,ACL_CATEGORY_BITMAP,BITCOUNT_Keyspecs,1,NULL,2),.args=BITCOUNT_Args},
 {MAKE_CMD("bitfield","Performs arbitrary bitfield integer operations on strings.","O(1) for each subcommand specified","3.2.0",CMD_DOC_NONE,NULL,NULL,"bitmap",COMMAND_GROUP_BITMAP,BITFIELD_History,0,BITFIELD_Tips,0,bitfieldCommand,-2,CMD_WRITE|CMD_DENYOOM,ACL_CATEGORY_BITMAP,BITFIELD_Keyspecs,1,bitfieldGetKeys,2),.args=BITFIELD_Args},
 {MAKE_CMD("bitfield_ro","Performs arbitrary read-only bitfield integer operations on strings.","O(1) for each subcommand specified","6.0.0",CMD_DOC_NONE,NULL,NULL,"bitmap",COMMAND_GROUP_BITMAP,BITFIELD_RO_History,0,BITFIELD_RO_Tips,0,bitfieldroCommand,-2,CMD_READONLY|CMD_FAST,ACL_CATEGORY_BITMAP,BITFIELD_RO_Keyspecs,1,NULL,2),.args=BITFIELD_RO_Args},
 {MAKE_CMD("bitop","Performs bitwise operations on multiple strings, and stores the result.","O(N)","2.6.0",CMD_DOC_NONE,NULL,NULL,"bitmap",COMMAND_GROUP_BITMAP,BITOP_History,0,BITOP_Tips,0,bitopCommand,-4,CMD_WRITE|CMD_DENYOOM,ACL_CATEGORY_BITMAP,BITOP_Keyspecs,2,NULL,3),.args=BITOP_Args},
diff --git a/src/commands/bitcount.json b/src/commands/bitcount.json
index 2d277a8551..ad90b39bad 100644
--- a/src/commands/bitcount.json
+++ b/src/commands/bitcount.json
@@ -10,6 +10,10 @@
             [
                 "7.0.0",
                 "Added the `BYTE|BIT` option."
+            ],
+            [
+                "8.0.0",
+                "`end` made optional; when called without argument the command reports the last BYTE."
             ]
         ],
         "command_flags": [
@@ -54,24 +58,31 @@
                         "type": "integer"
                     },
                     {
-                        "name": "end",
-                        "type": "integer"
-                    },
-                    {
-                        "name": "unit",
-                        "type": "oneof",
+                        "name": "end-unit-block",
+                        "type": "block",
                         "optional": true,
-                        "since": "7.0.0",
                         "arguments": [
                             {
-                                "name": "byte",
-                                "type": "pure-token",
-                                "token": "BYTE"
+                                "name": "end",
+                                "type": "integer"
                             },
                             {
-                                "name": "bit",
-                                "type": "pure-token",
-                                "token": "BIT"
+                                "name": "unit",
+                                "type": "oneof",
+                                "optional": true,
+                                "since": "7.0.0",
+                                "arguments": [
+                                    {
+                                        "name": "byte",
+                                        "type": "pure-token",
+                                        "token": "BYTE"
+                                    },
+                                    {
+                                        "name": "bit",
+                                        "type": "pure-token",
+                                        "token": "BIT"
+                                    }
+                                ]
                             }
                         ]
                     }
diff --git a/tests/unit/bitops.tcl b/tests/unit/bitops.tcl
index edcafdee07..125b0a3d1f 100644
--- a/tests/unit/bitops.tcl
+++ b/tests/unit/bitops.tcl
@@ -128,13 +128,26 @@ start_server {tags {"bitops"}} {
         }
     }
 
+    test {BITCOUNT with just start} {
+        set s "foobar"
+        r set s $s
+        assert_equal [r bitcount s 0] [count_bits "foobar"]
+        assert_equal [r bitcount s 1] [count_bits "oobar"]
+        assert_equal [r bitcount s 1000] 0
+        assert_equal [r bitcount s -1] [count_bits "r"]
+        assert_equal [r bitcount s -2] [count_bits "ar"]
+        assert_equal [r bitcount s -1000] [count_bits "foobar"]
+    }
+
     test {BITCOUNT with start, end} {
         set s "foobar"
         r set s $s
         assert_equal [r bitcount s 0 -1] [count_bits "foobar"]
         assert_equal [r bitcount s 1 -2] [count_bits "ooba"]
-        assert_equal [r bitcount s -2 1] [count_bits ""]
+        assert_equal [r bitcount s -2 1] 0
+        assert_equal [r bitcount s -1000 0] [count_bits "f"]
         assert_equal [r bitcount s 0 1000] [count_bits "foobar"]
+        assert_equal [r bitcount s -1000 1000] [count_bits "foobar"]
 
         assert_equal [r bitcount s 0 -1 bit] [count_bits $s]
         assert_equal [r bitcount s 10 14 bit] [count_bits_start_end $s 10 14]
@@ -144,18 +157,18 @@ start_server {tags {"bitops"}} {
         assert_equal [r bitcount s 3 -34 bit] [count_bits_start_end $s 3 14]
         assert_equal [r bitcount s 3 -19 bit] [count_bits_start_end $s 3 29]
         assert_equal [r bitcount s -2 1 bit] 0
+        assert_equal [r bitcount s -1000 14 bit] [count_bits_start_end $s 0 14]
         assert_equal [r bitcount s 0 1000 bit] [count_bits $s]
+        assert_equal [r bitcount s -1000 1000 bit] [count_bits $s]
     }
 
     test {BITCOUNT with illegal arguments} {
         # Used to return 0 for non-existing key instead of errors
         r del s
-        assert_error {ERR *syntax*} {r bitcount s 0}
         assert_error {ERR *syntax*} {r bitcount s 0 1 hello}
         assert_error {ERR *syntax*} {r bitcount s 0 1 hello hello2}
 
         r set s 1
-        assert_error {ERR *syntax*} {r bitcount s 0}
         assert_error {ERR *syntax*} {r bitcount s 0 1 hello}
         assert_error {ERR *syntax*} {r bitcount s 0 1 hello hello2}
     }