diff --git a/src/settings.jl b/src/settings.jl
index 22f38cd..68ba286 100644
--- a/src/settings.jl
+++ b/src/settings.jl
@@ -512,41 +512,55 @@ function check_for_duplicates(args::Vector{ArgParseField}, new_arg::ArgParseFiel
     return true
 end
 
-check_default_type(default::Nothing, arg_type::Type) = true
-function check_default_type(default::D, arg_type::Type) where D
-    D <: arg_type || serror("typeof(default)=$D is incompatible with arg_type=$arg_type)")
-    return true
+function typecompatible(default::D, arg_type::Type) where D
+    D <: arg_type && return true
+    try
+        applicable(convert, arg_type, default) ? convert(arg_type, default) : arg_type(default)
+        return true
+    catch
+    end
+    return false
 end
 
-check_default_type_multi_action(default::Nothing, arg_type::Type) = true
-function check_default_type_multi_action(default::Vector{D}, arg_type::Type) where D
-    arg_type <: D || serror("typeof(default)=Vector{$D} can't hold arguments of type arg_type=$arg_type)")
-    all(x->(x isa arg_type), default) || serror("all elements of the default value must be of type $arg_type)")
+check_default_type(default::Nothing, arg_type::Type) = true
+function check_default_type(default::D, arg_type::Type) where D
+    typecompatible(default, arg_type) || serror("typeof(default)=$D is incompatible with arg_type=$arg_type)")
     return true
 end
-check_default_type_multi_action(default::D, arg_type::Type) where D =
-    serror("typeof(default)=$D is incompatible with the action, it should be a Vector")
 
-check_default_type_multi_nargs(default::Nothing, arg_type::Type) = true
-function check_default_type_multi_nargs(default::Vector, arg_type::Type)
-    all(x->(x isa arg_type), default) || serror("all elements of the default value must be of type $arg_type")
+check_default_type_multi(default::Nothing, arg_type::Type) = true
+function check_default_type_multi(default::Vector, arg_type::Type)
+    all(x->typecompatible(x, arg_type), default) || serror("all elements of the default value must be of type $arg_type or convertible to it")
     return true
 end
-check_default_type_multi_nargs(default::D, arg_type::Type) where D =
+check_default_type_multi(default::D, arg_type::Type) where D =
     serror("typeof(default)=$D is incompatible with nargs, it should be a Vector")
 
 check_default_type_multi2(default::Nothing, arg_type::Type) = true
 function check_default_type_multi2(default::Vector{D}, arg_type::Type) where D
-    Vector{arg_type} <: D || serror("typeof(default)=Vector{$D} can't hold Vectors of arguments " *
-                                   "of type arg_type=$arg_type)")
     all(y->(y isa Vector), default) ||
         serror("the default $(default) is incompatible with the action and nargs, it should be a Vector of Vectors")
-    all(y->all(x->(x isa arg_type), y), default) || serror("all elements of the default value must be of type $arg_type")
+    all(y->all(x->typecompatible(x, arg_type), y), default) || serror("all elements of the default value must be of type $arg_type or convertible to it")
     return true
 end
 check_default_type_multi2(default::D, arg_type::Type) where D =
     serror("the default $(default) is incompatible with the action and nargs, it should be a Vector of Vectors")
 
+function _convert_default(arg_type::Type, default::D) where D
+    D <: arg_type && return default
+    applicable(convert, arg_type, default) ? convert(arg_type, default) : arg_type(default)
+end
+
+convert_default(arg_type::Type, default::Nothing) = nothing
+convert_default(arg_type::Type, default) = _convert_default(arg_type, default)
+
+convert_default_multi(arg_type::Type, default::Nothing) = Array{arg_type}(undef, 0)
+convert_default_multi(arg_type::Type, default::Vector) = arg_type[_convert_default(arg_type, x) for x in default]
+
+convert_default_multi2(arg_type::Type, default::Nothing) = Array{Vector{arg_type}}(undef, 0)
+convert_default_multi2(arg_type::Type, default::Vector) = Vector{arg_type}[arg_type[_convert_default(arg_type, x) for x in y] for y in default]
+
+
 check_range_default(default::Nothing, range_tester::Function) = true
 function check_range_default(default, range_tester::Function)
     local res::Bool
@@ -1033,20 +1047,17 @@ function add_arg_field!(settings::ArgParseSettings, name::ArgName; desc...)
         elseif action == :count_invocations
             new_arg.arg_type = Int
             new_arg.default = 0
-        elseif action ∈ (:store_const, :append_const)
-            if :arg_type ∈ supplied_opts
-                check_default_type(new_arg.default, new_arg.arg_type)
-                check_default_type(new_arg.constant, new_arg.arg_type)
-            else
-                if typeof(new_arg.default) == typeof(new_arg.constant)
-                    new_arg.arg_type = typeof(new_arg.default)
-                else
-                    new_arg.arg_type = Any
-                end
-            end
-            if action == :append_const && (new_arg.default ≡ nothing || new_arg.default == [])
-                new_arg.default = Array{new_arg.arg_type}(undef, 0)
+        elseif action == :store_const
+            check_default_type(new_arg.default, new_arg.arg_type)
+            check_default_type(new_arg.constant, new_arg.arg_type)
+            new_arg.default = convert_default(new_arg.arg_type, new_arg.default)
+        elseif action == :append_const
+            check_default_type(new_arg.constant, new_arg.arg_type)
+            if :arg_type ∉ supplied_opts
+                new_arg.arg_type = typeof(new_arg.constant)
             end
+            check_default_type_multi(new_arg.default, new_arg.arg_type)
+            new_arg.default = convert_default_multi(new_arg.arg_type, new_arg.default)
         elseif action == :command_flag
             # nothing to do
         elseif action == :show_help || action == :show_version
@@ -1062,28 +1073,22 @@ function add_arg_field!(settings::ArgParseSettings, name::ArgName; desc...)
         if !is_multi_action(new_arg.action) && !is_multi_nargs(new_arg.nargs)
             check_default_type(default, arg_type)
             check_range_default(default, range_tester)
-        elseif !is_multi_action(new_arg.action)
-            check_default_type_multi_nargs(default, arg_type)
-            check_range_default_multi(default, range_tester)
-        elseif !is_multi_nargs(new_arg.nargs)
-            check_default_type_multi_action(default, arg_type)
+            new_arg.default = convert_default(arg_type, default)
+        elseif !is_multi_action(new_arg.action) || !is_multi_nargs(new_arg.nargs)
+            check_default_type_multi(default, arg_type)
             check_range_default_multi(default, range_tester)
+            new_arg.default = convert_default_multi(arg_type, default)
         else
             check_default_type_multi2(default, arg_type)
             check_range_default_multi2(default, range_tester)
-        end
-        if (is_multi_action(new_arg.action) && is_multi_nargs(new_arg.nargs)) &&
-                (default ≡ nothing || default == [])
-            new_arg.default = Array{Vector{arg_type}}(undef, 0)
-        elseif (is_multi_action(new_arg.action) || is_multi_nargs(new_arg.nargs)) &&
-                (default ≡ nothing || default == [])
-            new_arg.default = Array{arg_type}(undef, 0)
+            new_arg.default = convert_default_multi2(arg_type, default)
         end
 
         if is_opt && nargs.desc == :?
             constant = new_arg.constant
             check_default_type(constant, arg_type)
             check_range_default(constant, range_tester)
+            new_arg.constant = convert_default(arg_type, constant)
         end
     end
 
diff --git a/test/argparse_test02.jl b/test/argparse_test02.jl
index 381c412..a9132cf 100644
--- a/test/argparse_test02.jl
+++ b/test/argparse_test02.jl
@@ -266,7 +266,7 @@ for s = [ap_settings2(), ap_settings2b(), ap_settings2c(), ap_settings2d(), ap_s
     @aps_test_throws @add_arg_table!(s, "required_arg_after_optional_args", required = true)
     # wrong default
     @aps_test_throws @add_arg_table!(s, "--opt", arg_type = Int, default = 1.5)
-    @aps_test_throws @add_arg_table!(s, "--opt3", arg_type = Symbol, default = "string")
+    @aps_test_throws @add_arg_table!(s, "--opt3", arg_type = Function, default = "string")
     # wrong range tester
     @aps_test_throws @add_arg_table!(s, "--opt", arg_type = Int, range_tester = x->string(x), default = 1)
     @aps_test_throws @add_arg_table!(s, "--opt", arg_type = Int, range_tester = x->sqrt(x)<1, default = -1)
diff --git a/test/argparse_test03.jl b/test/argparse_test03.jl
index dc056be..2096743 100644
--- a/test/argparse_test03.jl
+++ b/test/argparse_test03.jl
@@ -67,7 +67,7 @@ function ap_settings3()
                                                 # called repeatedly
             dest_name = "awk"
             range_tester = (x->x=="X"||x=="Y")  # each argument must be either "X" or "Y"
-            default = Any[Any["X"]]
+            default = [["X"]]
             metavar = "XY"
             help = "either X or Y; all XY's are " *
                    "stored in chunks"
@@ -113,7 +113,7 @@ let s = ap_settings3()
           --collect C           collect things (type: $Int)
           --awkward-option XY [XY...]
                                 either X or Y; all XY's are stored in chunks
-                                (default: Any[Any["X"]])
+                                (default: $(Vector{Any})[["X"]])
 
         """
 
@@ -134,8 +134,8 @@ let s = ap_settings3()
     @aps_test_throws @add_arg_table!(s, "--opt", action = :store_const, arg_type = Int, default = 1, constant = 1.5)
     @aps_test_throws @add_arg_table!(s, "--opt", action = :append_const, arg_type = Int, constant = 1.5)
     # wrong defaults
-    @aps_test_throws @add_arg_table!(s, "--opt", action = :append_arg, arg_type = Int, default = Float64[])
-    @aps_test_throws @add_arg_table!(s, "--opt", action = :append_arg, nargs = '+', arg_type = Int, default = Vector{Float64}[])
+    @aps_test_throws @add_arg_table!(s, "--opt", action = :append_arg, arg_type = Int, default = String["hello"])
+    @aps_test_throws @add_arg_table!(s, "--opt", action = :append_arg, nargs = '+', arg_type = Int, default = Vector{Float64}[[1.5]])
     @aps_test_throws @add_arg_table!(s, "--opt", action = :store_arg, nargs = '+', arg_type = Int, default = [1.5])
     @aps_test_throws @add_arg_table!(s, "--opt", action = :store_arg, nargs = '+', arg_type = Int, default = 1)
     @aps_test_throws @add_arg_table!(s, "--opt", action = :append_arg, arg_type = Int, range_tester=x->x<=1, default = Int[0, 1, 2])
@@ -156,9 +156,9 @@ let s = ap_settings3()
     # allow ambiguous options
     s.allow_ambiguous_opts = true
     @add_arg_table!(s, "-2", action = :store_true)
-    @test ap_test3([]) == Dict{String,Any}("O_stack"=>String[], "k"=>0, "u"=>0, "array"=>[7, 3, 2], "custom"=>CustomType(), "oddint"=>1, "collect"=>[], "awk"=>Any[Any["X"]], "2"=>false)
-    @test ap_test3(["-2"]) == Dict{String,Any}("O_stack"=>String[], "k"=>0, "u"=>0, "array"=>[7, 3, 2], "custom"=>CustomType(), "oddint"=>1, "collect"=>[], "awk"=>Any[["X"]], "2"=>true)
-    @test ap_test3(["--awk", "X", "-2"]) == Dict{String,Any}("O_stack"=>String[], "k"=>0, "u"=>0, "array"=>[7, 3, 2], "custom"=>CustomType(), "oddint"=>1, "collect"=>[], "awk"=>Any[Any["X"], Any["X"]], "2"=>true)
+    @test ap_test3([]) == Dict{String,Any}("O_stack"=>String[], "k"=>0, "u"=>0, "array"=>[7, 3, 2], "custom"=>CustomType(), "oddint"=>1, "collect"=>[], "awk"=>Vector{Any}[["X"]], "2"=>false)
+    @test ap_test3(["-2"]) == Dict{String,Any}("O_stack"=>String[], "k"=>0, "u"=>0, "array"=>[7, 3, 2], "custom"=>CustomType(), "oddint"=>1, "collect"=>[], "awk"=>Vector{Any}[["X"]], "2"=>true)
+    @test ap_test3(["--awk", "X", "-2"]) == Dict{String,Any}("O_stack"=>String[], "k"=>0, "u"=>0, "array"=>[7, 3, 2], "custom"=>CustomType(), "oddint"=>1, "collect"=>[], "awk"=>Vector{Any}[["X"], ["X"]], "2"=>true)
     @ap_test_throws ap_test3(["--awk", "X", "-3"])
 
 end
diff --git a/test/argparse_test14.jl b/test/argparse_test14.jl
new file mode 100644
index 0000000..3494661
--- /dev/null
+++ b/test/argparse_test14.jl
@@ -0,0 +1,71 @@
+# test 14: default values converted to arg_type
+
+@testset "test 14" begin
+
+function ap_settings14()
+
+    s = ArgParseSettings(description = "Test 14 for ArgParse.jl",
+                         exc_handler = ArgParse.debug_handler)
+
+    @add_arg_table! s begin
+        "--opt1"
+            nargs = '?'
+            arg_type = Int
+            default = 0.0
+            constant = 1.0
+            help = "an option"
+        "-O"
+            arg_type = Symbol
+            default = "xyz"
+            help = "another option"
+        "--opt2"
+            nargs = '+'
+            arg_type = Int
+            default = [0.0]
+            help = "another option"
+        "--opt3"
+            action = :append_arg
+            arg_type = Int
+            default = [0.0]
+            help = "another option"
+        "--opt4"
+            action = :append_arg
+            nargs = '+'
+            arg_type = Int
+            default = [[0.0]]
+            help = "another option"
+    end
+
+    return s
+end
+
+let s = ap_settings14()
+    ap_test14(args) = parse_args(args, s)
+
+    @test stringhelp(s) == """
+        usage: $(basename(Base.source_path())) [--opt1 [OPT1]] [-O O]
+                                [--opt2 OPT2 [OPT2...]] [--opt3 OPT3]
+                                [--opt4 OPT4 [OPT4...]]
+
+        Test 14 for ArgParse.jl
+
+        optional arguments:
+          --opt1 [OPT1]         an option (type: Int64, default: 0, without
+                                arg: 1)
+          -O O                  another option (type: Symbol, default: :xyz)
+          --opt2 OPT2 [OPT2...]
+                                another option (type: Int64, default: [0])
+          --opt3 OPT3           another option (type: Int64, default: [0])
+          --opt4 OPT4 [OPT4...]
+                                another option (type: Int64, default: [[0]])
+
+        """
+
+    @test ap_test14([]) == Dict{String,Any}("opt1"=>0, "O"=>:xyz, "opt2"=>[0], "opt3"=>[0], "opt4"=>[[0]])
+    @test ap_test14(["--opt1"]) == Dict{String,Any}("opt1"=>1, "O"=>:xyz, "opt2"=>[0], "opt3"=>[0], "opt4"=>[[0]])
+    @test ap_test14(["--opt1", "33", "--opt2", "5", "7"]) == Dict{String,Any}("opt1"=>33, "O"=>:xyz, "opt2"=>[5, 7], "opt3"=>[0], "opt4"=>[[0]])
+    @test ap_test14(["--opt3", "5", "--opt3", "7"]) == Dict{String,Any}("opt1"=>0, "O"=>:xyz, "opt2"=>[0], "opt3"=>[0, 5, 7], "opt4"=>[[0]])
+    @test ap_test14(["--opt4", "5", "7", "--opt4", "11", "13", "17"]) == Dict{String,Any}("opt1"=>0, "O"=>:xyz, "opt2"=>[0], "opt3"=>[0], "opt4"=>[[0], [5, 7], [11, 13, 17]])
+end
+
+end
diff --git a/test/runtests.jl b/test/runtests.jl
index dbcd279..bd030ba 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -2,7 +2,7 @@ module ArgParseTests
 
 include("common.jl")
 
-for i = 1:13
+for i = 1:14
     try
         s_i = lpad(string(i), 2, "0")
         include("argparse_test$s_i.jl")