diff --git a/include/CLI/TypeTools.hpp b/include/CLI/TypeTools.hpp
index 5c2689771..4b56f10c5 100644
--- a/include/CLI/TypeTools.hpp
+++ b/include/CLI/TypeTools.hpp
@@ -968,6 +968,9 @@ bool integral_conversion(const std::string &input, T &output) noexcept {
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '\''), nstring.end());
         return integral_conversion(nstring, output);
     }
+    if(std::isspace(static_cast<unsigned char>(input.back()))) {
+        return integral_conversion(trim_copy(input), output);
+    }
     if(input.compare(0, 2, "0o") == 0 || input.compare(0, 2, "0O") == 0) {
         val = nullptr;
         errno = 0;
@@ -1016,13 +1019,16 @@ bool integral_conversion(const std::string &input, T &output) noexcept {
         output = static_cast<T>(1);
         return true;
     }
-    // remove separators
+    // remove separators and trailing spaces
     if(input.find_first_of("_'") != std::string::npos) {
         std::string nstring = input;
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '_'), nstring.end());
         nstring.erase(std::remove(nstring.begin(), nstring.end(), '\''), nstring.end());
         return integral_conversion(nstring, output);
     }
+    if(std::isspace(static_cast<unsigned char>(input.back()))) {
+        return integral_conversion(trim_copy(input), output);
+    }
     if(input.compare(0, 2, "0o") == 0 || input.compare(0, 2, "0O") == 0) {
         val = nullptr;
         errno = 0;
@@ -1147,6 +1153,13 @@ bool lexical_cast(const std::string &input, T &output) {
     if(val == (input.c_str() + input.size())) {
         return true;
     }
+    while(std::isspace(static_cast<unsigned char>(*val))) {
+        ++val;
+        if(val == (input.c_str() + input.size())) {
+            return true;
+        }
+    }
+
     // remove separators
     if(input.find_first_of("_'") != std::string::npos) {
         std::string nstring = input;
diff --git a/tests/OptionTypeTest.cpp b/tests/OptionTypeTest.cpp
index c30127559..212626496 100644
--- a/tests/OptionTypeTest.cpp
+++ b/tests/OptionTypeTest.cpp
@@ -227,9 +227,13 @@ TEST_CASE_METHOD(TApp, "atomic_int_option", "[optiontype]") {
 static const std::map<std::string, double> testValuesDouble{
     {"3.14159", 3.14159},
     {"-3.14159", -3.14159},
+    {"-3.14159\t", -3.14159},
+    {"-3.14159  ", -3.14159},
     {"+1.0", 1.0},
     {"-0.01", -0.01},
     {"5e22", 5e22},
+    {" 5e22", 5e22},
+    {" 5e22  ", 5e22},
     {"-2E-2", -2e-2},
     {"5e+22", 5e22},
     {"1e06", 1e6},
@@ -268,6 +272,7 @@ static const std::map<std::string, std::int64_t> testValuesInt{
     {"+99", 99},
     {"99", 99},
     {"-99", -99},
+    {"-99 ", -99},
     {"0xDEADBEEF", 0xDEADBEEF},
     {"0xdeadbeef", 0xDEADBEEF},
     {"0XDEADBEEF", 0xDEADBEEF},
@@ -280,6 +285,7 @@ static const std::map<std::string, std::int64_t> testValuesInt{
     {"995862_262", 995862262},
     {"995862262", 995862262},
     {"-995862275", -995862275},
+    {"\t-995862275\t", -995862275},
     {"-995'862'275", -995862275},
     {"0b11010110", 0xD6},
     {"0b1101'0110", 0xD6},
@@ -323,6 +329,7 @@ TEST_CASE_METHOD(TApp, "intConversionsErange", "[optiontype]") {
 static const std::map<std::string, std::uint64_t> testValuesUInt{
     {"+99", 99},
     {"99", 99},
+    {" 99 ", 99},
     {"0xDEADBEEF", 0xDEADBEEF},
     {"0xdeadbeef", 0xDEADBEEF},
     {"0XDEADBEEF", 0xDEADBEEF},
@@ -331,13 +338,16 @@ static const std::map<std::string, std::uint64_t> testValuesUInt{
     {"0xdead'beef", 0xDEADBEEF},
     {"0o01234567", 001234567},
     {"0o755", 0755},
+    {"0o755\t", 0755},
     {"0755", 0755},
     {"995862_262", 995862262},
     {"995862262", 995862262},
     {"+995862275", +995862275},
+    {"+995862275         \n\t", +995862275},
     {"995'862'275", 995862275},
     {"0b11010110", 0xD6},
     {"0b1101'0110", 0xD6},
+    {"0b1101'0110                                                       ", 0xD6},
     {"0B11010110", 0xD6},
     {"0B1101'0110", 0xD6},
     {"1_2_3_4_5", 12345},