diff --git a/Sources/Plasma/CoreLib/plFormat.cpp b/Sources/Plasma/CoreLib/plFormat.cpp
index abe8c465..1ab5c5a8 100644
--- a/Sources/Plasma/CoreLib/plFormat.cpp
+++ b/Sources/Plasma/CoreLib/plFormat.cpp
@@ -45,6 +45,7 @@ Mead, WA   99021
 #include "HeadSpin.h"
 #include <cstdlib>
 #include <cstring>
+#include <type_traits>
 
 #define BADCHAR_REPLACEMENT (0xFFFDul)
 
@@ -226,7 +227,8 @@ static void _formatNumeric(const plFormat_Private::FormatSpec &format,
                            plStringStream &output, _IType value,
                            int radix, bool upperCase = false)
 {
-    char pad = format.fPadChar ? format.fPadChar : ' ';
+    static_assert(std::is_unsigned<_IType>::value,
+            "Signed numerics are currently only supported in Decimal formatting");
 
     size_t format_size = 0;
     _IType temp = value;
@@ -250,8 +252,8 @@ template <typename _IType>
 static void _formatDecimal(const plFormat_Private::FormatSpec &format,
                            plStringStream &output, _IType value)
 {
-    char pad = format.fPadChar ? format.fPadChar : ' ';
-    _IType abs = (value < 0) ? -value : value;
+    typedef typename std::make_unsigned<_IType>::type _UType;
+    _UType abs = (value < 0) ? -(_UType)value : value;
 
     size_t format_size = 0;
     _IType temp = abs;
@@ -266,18 +268,15 @@ static void _formatDecimal(const plFormat_Private::FormatSpec &format,
     if (value < 0 || format.fDigitClass == plFormat_Private::kDigitDecAlwaysSigned)
         ++format_size;
 
-    hsAssert(format_size < 21, "Format length too long");
-
-    char buffer[21];
-    _IFormatNumeric_Impl<_IType>(buffer + format_size, abs, 10);
+    hsAssert(format_size < 24, "Format length too long");
 
-    int signPos = arrsize(buffer) - static_cast<int>(format_size);
-    hsAssert(signPos >= 0, "Format buffer not large enough for sign");
+    char buffer[24];
+    _IFormatNumeric_Impl<_UType>(buffer + format_size, abs, 10);
 
     if (value < 0)
-        buffer[signPos] = '-';
+        buffer[0] = '-';
     else if (format.fDigitClass == plFormat_Private::kDigitDecAlwaysSigned)
-        buffer[signPos] = '+';
+        buffer[0] = '+';
 
     _formatString(format, output, buffer, format_size, plFormat_Private::kAlignRight);
 }
@@ -477,20 +476,20 @@ PL_FORMAT_IMPL(wchar_t)
 {
     switch (format.fDigitClass) {
     case plFormat_Private::kDigitBin:
-        _formatNumeric<wchar_t>(format, output, value, 2);
+        _formatNumeric<uint32_t>(format, output, value, 2);
         break;
     case plFormat_Private::kDigitOct:
-        _formatNumeric<wchar_t>(format, output, value, 8);
+        _formatNumeric<uint32_t>(format, output, value, 8);
         break;
     case plFormat_Private::kDigitHex:
-        _formatNumeric<wchar_t>(format, output, value, 16, false);
+        _formatNumeric<uint32_t>(format, output, value, 16, false);
         break;
     case plFormat_Private::kDigitHexUpper:
-        _formatNumeric<wchar_t>(format, output,value, 16, true);
+        _formatNumeric<uint32_t>(format, output, value, 16, true);
         break;
     case plFormat_Private::kDigitDec:
     case plFormat_Private::kDigitDecAlwaysSigned:
-        _formatDecimal<wchar_t>(format, output, value);
+        _formatDecimal<uint32_t>(format, output, value);
         break;
     case plFormat_Private::kDigitChar:
     case plFormat_Private::kDigitDefault:
diff --git a/Sources/Tests/CoreTests/test_plFormat.cpp b/Sources/Tests/CoreTests/test_plFormat.cpp
index 39b3de38..a15e8705 100644
--- a/Sources/Tests/CoreTests/test_plFormat.cpp
+++ b/Sources/Tests/CoreTests/test_plFormat.cpp
@@ -3,6 +3,7 @@
 
 #include <gtest/gtest.h>
 #include <string>
+#include <limits>
 
 TEST(plFormat, Escapes)
 {
@@ -83,3 +84,62 @@ TEST(plFormat, Char)
     EXPECT_EQ(plString("xx\xf4\x8f\xbf\xbfxx"), plFormat("xx{c}xx", (int64_t)0x10ffff));
     EXPECT_EQ(plString("xx\xf4\x8f\xbf\xbfxx"), plFormat("xx{c}xx", (uint64_t)0x10ffff));
 }
+
+TEST(plFormat, Decimal)
+{
+    EXPECT_EQ(plString("xx1234xx"), plFormat("xx{}xx", 1234));
+    EXPECT_EQ(plString("xx1234xx"), plFormat("xx{d}xx", 1234));
+    EXPECT_EQ(plString("xx1234xx"), plFormat("xx{2}xx", 1234));
+    EXPECT_EQ(plString("xx1234xx"), plFormat("xx{>2}xx", 1234));
+    EXPECT_EQ(plString("xx1234xx"), plFormat("xx{<2}xx", 1234));
+    EXPECT_EQ(plString("xx  1234xx"), plFormat("xx{6}xx", 1234));
+    EXPECT_EQ(plString("xx  1234xx"), plFormat("xx{>6}xx", 1234));
+    EXPECT_EQ(plString("xx1234  xx"), plFormat("xx{<6}xx", 1234));
+
+    // Character types
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{d}xx", '\0'));
+    EXPECT_EQ(plString("xx65xx"), plFormat("xx{d}xx", 'A'));
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{d}xx", L'\0'));
+    EXPECT_EQ(plString("xx65xx"), plFormat("xx{d}xx", L'A'));
+    EXPECT_EQ(plString("xx32767xx"), plFormat("xx{d}xx", L'\u7fff'));
+
+    // Numeric char types
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (signed char)0));
+    EXPECT_EQ(plString("xx127xx"), plFormat("xx{}xx", std::numeric_limits<signed char>::max()));
+    EXPECT_EQ(plString("xx+127xx"), plFormat("xx{+}xx", std::numeric_limits<signed char>::max()));
+    EXPECT_EQ(plString("xx-128xx"), plFormat("xx{}xx", std::numeric_limits<signed char>::min()));
+    EXPECT_EQ(plString("xx-128xx"), plFormat("xx{+}xx", std::numeric_limits<signed char>::min()));
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (unsigned char)0));
+    EXPECT_EQ(plString("xx255xx"), plFormat("xx{}xx", std::numeric_limits<unsigned char>::max()));
+    EXPECT_EQ(plString("xx+255xx"), plFormat("xx{+}xx", std::numeric_limits<unsigned char>::max()));
+
+    // 16-bit ints
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (short)0));
+    EXPECT_EQ(plString("xx32767xx"), plFormat("xx{}xx", std::numeric_limits<short>::max()));
+    EXPECT_EQ(plString("xx+32767xx"), plFormat("xx{+}xx", std::numeric_limits<short>::max()));
+    EXPECT_EQ(plString("xx-32768xx"), plFormat("xx{}xx", std::numeric_limits<short>::min()));
+    EXPECT_EQ(plString("xx-32768xx"), plFormat("xx{+}xx", std::numeric_limits<short>::min()));
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (unsigned short)0));
+    EXPECT_EQ(plString("xx65535xx"), plFormat("xx{}xx", std::numeric_limits<unsigned short>::max()));
+    EXPECT_EQ(plString("xx+65535xx"), plFormat("xx{+}xx", std::numeric_limits<unsigned short>::max()));
+
+    // 32-bit ints
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (int)0));
+    EXPECT_EQ(plString("xx2147483647xx"), plFormat("xx{}xx", std::numeric_limits<int>::max()));
+    EXPECT_EQ(plString("xx+2147483647xx"), plFormat("xx{+}xx", std::numeric_limits<int>::max()));
+    EXPECT_EQ(plString("xx-2147483648xx"), plFormat("xx{}xx", std::numeric_limits<int>::min()));
+    EXPECT_EQ(plString("xx-2147483648xx"), plFormat("xx{+}xx", std::numeric_limits<int>::min()));
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (unsigned int)0));
+    EXPECT_EQ(plString("xx4294967295xx"), plFormat("xx{}xx", std::numeric_limits<unsigned int>::max()));
+    EXPECT_EQ(plString("xx+4294967295xx"), plFormat("xx{+}xx", std::numeric_limits<unsigned int>::max()));
+
+    // 64-bit ints
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (int64_t)0));
+    EXPECT_EQ(plString("xx9223372036854775807xx"), plFormat("xx{}xx", std::numeric_limits<int64_t>::max()));
+    EXPECT_EQ(plString("xx+9223372036854775807xx"), plFormat("xx{+}xx", std::numeric_limits<int64_t>::max()));
+    EXPECT_EQ(plString("xx-9223372036854775808xx"), plFormat("xx{}xx", std::numeric_limits<int64_t>::min()));
+    EXPECT_EQ(plString("xx-9223372036854775808xx"), plFormat("xx{+}xx", std::numeric_limits<int64_t>::min()));
+    EXPECT_EQ(plString("xx0xx"), plFormat("xx{}xx", (uint64_t)0));
+    EXPECT_EQ(plString("xx18446744073709551615xx"), plFormat("xx{}xx", std::numeric_limits<uint64_t>::max()));
+    EXPECT_EQ(plString("xx+18446744073709551615xx"), plFormat("xx{+}xx", std::numeric_limits<uint64_t>::max()));
+}