diff --git a/binding/erlang/src/ip2region_util.erl b/binding/erlang/src/ip2region_util.erl
index 0359b85..df892f9 100644
--- a/binding/erlang/src/ip2region_util.erl
+++ b/binding/erlang/src/ip2region_util.erl
@@ -2,25 +2,65 @@
 %% Copyright 2022 The Ip2Region Authors. All rights reserved.
 %% Use of this source code is governed by a Apache2.0-style
 %% license that can be found in the LICENSE file.
-%% 
-%% @doc 
-%% ip2region utils
+%%
+%% @doc
+%% ip2region utils: IPv4/IPv6 parsing and version detection.
 %% @end
 %%%-------------------------------------------------------------------
 -module(ip2region_util).
--export([ipv4_to_n/1]).
 
+-export([ipv4_to_n/1, ip_version/1, ip_to_bytes/1]).
 
-ipv4_to_n(IntIp) when is_integer(IntIp) -> IntIp;
-ipv4_to_n({A, B, C, D}) ->
-	<<N:32>> = <<A, B, C, D>>,
-	N;
-ipv4_to_n(Ip) when is_binary(Ip) ->
-	ipv4_to_n(binary_to_list(Ip));
-ipv4_to_n(Ip) when is_list(Ip) ->
+-spec ip_version(Ip :: tuple() | list() | binary() | integer()) ->
+    ipv4 | ipv6 | {error, atom()}.
+ip_version(Ip) when is_integer(Ip) -> ipv4;
+ip_version({_, _, _, _}) -> ipv4;
+ip_version({_, _, _, _, _, _, _, _}) -> ipv6;
+ip_version(Ip) when is_binary(Ip) ->
+    ip_version(binary_to_list(Ip));
+ip_version(Ip) when is_list(Ip) ->
     case inet_parse:address(Ip) of
-        {ok, Addr} ->
-            ipv4_to_n(Addr);
+        {ok, {_, _, _, _}} -> ipv4;
+        {ok, {_, _, _, _, _, _, _, _}} -> ipv6;
+        _ -> {error, bad_ip_format}
+    end;
+ip_version(_) ->
+    {error, bad_ip_format}.
+
+-spec ip_to_bytes(Ip :: tuple() | list() | binary() | integer()) ->
+    {ok, ipv4 | ipv6, binary()} | {error, atom()}.
+ip_to_bytes(Ip) when is_integer(Ip) ->
+    {ok, ipv4, <<Ip:32>>};
+ip_to_bytes({A, B, C, D}) ->
+    {ok, ipv4, <<A, B, C, D>>};
+ip_to_bytes({A, B, C, D, E, F, G, H}) ->
+    {ok, ipv6, <<A:16, B:16, C:16, D:16, E:16, F:16, G:16, H:16>>};
+ip_to_bytes(Ip) when is_binary(Ip) ->
+    ip_to_bytes(binary_to_list(Ip));
+ip_to_bytes(Ip) when is_list(Ip) ->
+    case inet_parse:address(Ip) of
+        {ok, {A, B, C, D}} ->
+            {ok, ipv4, <<A, B, C, D>>};
+        {ok, {A, B, C, D, E, F, G, H}} ->
+            {ok, ipv6, <<A:16, B:16, C:16, D:16, E:16, F:16, G:16, H:16>>};
         _ ->
             {error, bad_ip_format}
-    end.
\ No newline at end of file
+    end;
+ip_to_bytes(_) ->
+    {error, bad_ip_format}.
+
+-spec ipv4_to_n(Ip :: tuple() | list() | binary() | integer()) ->
+    non_neg_integer() | {error, atom()}.
+ipv4_to_n(IntIp) when is_integer(IntIp) -> IntIp;
+ipv4_to_n({A, B, C, D}) ->
+    <<N:32>> = <<A, B, C, D>>,
+    N;
+ipv4_to_n(Ip) when is_binary(Ip) ->
+    ipv4_to_n(binary_to_list(Ip));
+ipv4_to_n(Ip) when is_list(Ip) ->
+    case ip_to_bytes(Ip) of
+        {ok, ipv4, <<N:32>>} -> N;
+        _ -> {error, bad_ip_format}
+    end;
+ipv4_to_n(_) ->
+    {error, bad_ip_format}.
diff --git a/binding/erlang/test/ip2region_util_test.erl b/binding/erlang/test/ip2region_util_test.erl
new file mode 100644
index 0000000..200f0a0
--- /dev/null
+++ b/binding/erlang/test/ip2region_util_test.erl
@@ -0,0 +1,42 @@
+-module(ip2region_util_test).
+-include_lib("eunit/include/eunit.hrl").
+
+ipv4_inputs_test_() ->
+    [
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes("1.0.8.0")),
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes(<<"1.0.8.0">>)),
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes({1,0,8,0})),
+        ?_assertEqual({ok, ipv4, <<1,0,8,0>>}, ip2region_util:ip_to_bytes(16779264)),
+        ?_assertEqual(ipv4, ip2region_util:ip_version("1.0.8.0")),
+        ?_assertEqual(ipv4, ip2region_util:ip_version({1,0,8,0}))
+    ].
+
+ipv6_inputs_test_() ->
+    [
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1>>},
+                      ip2region_util:ip_to_bytes("::1")),
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,255,255,1,0,8,0>>},
+                      ip2region_util:ip_to_bytes("::ffff:1.0.8.0")),
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,255,255,1,0,8,0>>},
+                      ip2region_util:ip_to_bytes(<<"::ffff:1.0.8.0">>)),
+        ?_assertEqual({ok, ipv6, <<0,0,0,0,0,0,0,0,0,0,255,255,1,0,8,0>>},
+                      ip2region_util:ip_to_bytes({0,0,0,0,0,65535,256,2048})),
+        ?_assertEqual(ipv6, ip2region_util:ip_version("::1")),
+        ?_assertEqual(ipv6, ip2region_util:ip_version({0,0,0,0,0,0,0,1}))
+    ].
+
+invalid_inputs_test_() ->
+    [
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes("xxx.0.8.0")),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes("::ggg")),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes({1,2,3})),
+        ?_assertEqual({error, bad_ip_format}, ip2region_util:ip_to_bytes(atom))
+    ].
+
+legacy_ipv4_to_n_test_() ->
+    [
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n("1.0.8.0")),
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n(<<"1.0.8.0">>)),
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n({1,0,8,0})),
+        ?_assertEqual(16779264, ip2region_util:ipv4_to_n(16779264))
+    ].