diff --git a/libs/gfx/include/psemek/gfx/mesh.hpp b/libs/gfx/include/psemek/gfx/mesh.hpp
index a539090c..e583d6af 100644
--- a/libs/gfx/include/psemek/gfx/mesh.hpp
+++ b/libs/gfx/include/psemek/gfx/mesh.hpp
@@ -384,6 +384,9 @@ namespace psemek::gfx
 		template <typename T>
 		static constexpr GLenum gl_type_v = gl_type<T>::value;
 
+		void check_vertex_size(std::size_t vertex_size, std::size_t stride);
+		void check_instance_size(std::size_t instance_size, std::size_t stride);
+
 	}
 
 	struct mesh
@@ -412,8 +415,7 @@ namespace psemek::gfx
 		template <typename Vertex>
 		void load(Vertex const * vertices, std::size_t count, GLenum primitive_type, GLenum usage = gl::STREAM_DRAW)
 		{
-			if (sizeof(Vertex) != stride_)
-				throw std::runtime_error("Vertex size not equal to sum of attribute sizes");
+			detail::check_vertex_size(sizeof(Vertex), stride_);
 
 			switch (primitive_type)
 			{
@@ -532,8 +534,7 @@ namespace psemek::gfx
 		template <typename Vertex, typename Index>
 		void load(Vertex const * vertices, std::size_t vertex_count, Index const * indices, std::size_t index_count, GLenum primitive_type, GLenum usage = gl::STREAM_DRAW)
 		{
-			if (sizeof(Vertex) != stride_)
-				throw std::runtime_error("Vertex size not equal to sum of attribute sizes");
+			detail::check_vertex_size(sizeof(Vertex), stride_);
 
 			switch (primitive_type)
 			{
@@ -658,8 +659,7 @@ namespace psemek::gfx
 		template <typename Vertex>
 		void load(Vertex const * vertices, std::size_t count, GLenum primitive_type, GLenum usage = gl::STREAM_DRAW)
 		{
-			if (sizeof(Vertex) != stride_)
-				throw std::runtime_error("Vertex size not equal to sum of attribute sizes");
+			detail::check_vertex_size(sizeof(Vertex), stride_);
 
 			switch (primitive_type)
 			{
@@ -722,8 +722,7 @@ namespace psemek::gfx
 		template <typename Instance>
 		void load_instance(Instance const * instances, std::size_t count, GLenum usage = gl::STREAM_DRAW)
 		{
-			if (sizeof(Instance) != instance_stride_)
-				throw std::runtime_error("Instance size not equal to sum of instanced attribute sizes");
+			detail::check_instance_size(sizeof(Instance), instance_stride_);
 
 			gl::BindBuffer(gl::ARRAY_BUFFER, instance_buffer_);
 			gl::BufferData(gl::ARRAY_BUFFER, count * sizeof(Instance), instances, usage);
diff --git a/libs/gfx/source/mesh.cpp b/libs/gfx/source/mesh.cpp
index 843be4f6..02741672 100644
--- a/libs/gfx/source/mesh.cpp
+++ b/libs/gfx/source/mesh.cpp
@@ -1,8 +1,27 @@
 #include <psemek/gfx/mesh.hpp>
 
+#include <psemek/util/to_string.hpp>
+
 namespace psemek::gfx
 {
 
+	namespace detail
+	{
+
+		void check_vertex_size(std::size_t vertex_size, std::size_t stride)
+		{
+			if (vertex_size != stride)
+				throw std::runtime_error(util::to_string("Vertex size (", vertex_size, ") not equal to sum of attribute sizes (", stride, ")"));
+		}
+
+		void check_instance_size(std::size_t instance_size, std::size_t stride)
+		{
+			if (instance_size != stride)
+				throw std::runtime_error(util::to_string("Instance size (", instance_size, ") not equal to sum of instanced attribute sizes (", stride, ")"));
+		}
+
+	}
+
 	mesh mesh::null()
 	{
 		return mesh(0);