diff --git a/src/compiler/lexer.c b/src/compiler/lexer.c
index 6b5d55808..3a09cffd1 100644
--- a/src/compiler/lexer.c
+++ b/src/compiler/lexer.c
@@ -3,6 +3,7 @@
 // a copy of which can be found in the LICENSE file.
 
 #include "compiler_internal.h"
+#include "errno.h"
 
 typedef enum
 {
@@ -426,7 +427,12 @@ static inline bool scan_hex(Lexer *lexer)
 		// Possibly we should move to a BigDecimal implementation or at least a soft float 256
 		// implementation for the constants.
 		char *end = NULL;
+		errno = 0;
 		long double fval = strtold(lexer->lexing_start, &end);
+		if (errno == ERANGE)
+		{
+			return add_error_token(lexer, "The float value is out of range.");
+		}
 		if (end != lexer->current)
 		{
 			return add_error_token(lexer, "Invalid float value.");
diff --git a/src/compiler/sema_casts.c b/src/compiler/sema_casts.c
index 24fdc4b3b..53cdc6478 100644
--- a/src/compiler/sema_casts.c
+++ b/src/compiler/sema_casts.c
@@ -615,7 +615,7 @@ bool may_convert_float_const_implicit(Expr *expr, Type *to_type)
 		default:
 			UNREACHABLE
 	}
-	if (expr->const_expr.f < -limit && expr->const_expr.f > limit)
+	if (expr->const_expr.f < -limit || expr->const_expr.f > limit)
 	{
 		SEMA_ERROR(expr, "The value '%Lg' is out of range for %s, so you need an explicit cast to truncate the value.", expr->const_expr.f, type_quoted_error_string(to_type));
 		return false;
diff --git a/test/test_suite/floats/explicit_float_truncation_needed.c3 b/test/test_suite/floats/explicit_float_truncation_needed.c3
new file mode 100644
index 000000000..6bd4792fe
--- /dev/null
+++ b/test/test_suite/floats/explicit_float_truncation_needed.c3
@@ -0,0 +1,4 @@
+func void test()
+{
+    float x = 0x7FFFFFFFFFFF.0p+400; // #error: The value '3.63419e+134' is out of range for 'float', so you need an explicit cast to truncate the value
+}
\ No newline at end of file
diff --git a/test/test_suite/floats/float_exceeding_size.c3 b/test/test_suite/floats/float_exceeding_size.c3
new file mode 100644
index 000000000..0d198b3d9
--- /dev/null
+++ b/test/test_suite/floats/float_exceeding_size.c3
@@ -0,0 +1,5 @@
+func void test()
+{
+    float x = 0x7FFFFFFFFFFF.0p+40000; // #error: The float value is out of range.
+
+}
\ No newline at end of file