diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -1642,20 +1642,20 @@ public:
 		this->smallest_y = std::max(min_inf_height, min_acs_height + WidgetDimensions::scaled.vsep_wide + min_avs_height);
 
 		/* Filling. */
-		this->fill_x = LeastCommonMultiple(this->avs->fill_x, this->acs->fill_x);
+		this->fill_x = std::lcm(this->avs->fill_x, this->acs->fill_x);
 		if (this->inf->fill_x > 0 && (this->fill_x == 0 || this->fill_x > this->inf->fill_x)) this->fill_x = this->inf->fill_x;
 
 		this->fill_y = this->avs->fill_y;
 		if (this->acs->fill_y > 0 && (this->fill_y == 0 || this->fill_y > this->acs->fill_y)) this->fill_y = this->acs->fill_y;
-		this->fill_y = LeastCommonMultiple(this->fill_y, this->inf->fill_y);
+		this->fill_y = std::lcm(this->fill_y, this->inf->fill_y);
 
 		/* Resizing. */
-		this->resize_x = LeastCommonMultiple(this->avs->resize_x, this->acs->resize_x);
+		this->resize_x = std::lcm(this->avs->resize_x, this->acs->resize_x);
 		if (this->inf->resize_x > 0 && (this->resize_x == 0 || this->resize_x > this->inf->resize_x)) this->resize_x = this->inf->resize_x;
 
 		this->resize_y = this->avs->resize_y;
 		if (this->acs->resize_y > 0 && (this->resize_y == 0 || this->resize_y > this->acs->resize_y)) this->resize_y = this->acs->resize_y;
-		this->resize_y = LeastCommonMultiple(this->resize_y, this->inf->resize_y);
+		this->resize_y = std::lcm(this->resize_y, this->inf->resize_y);
 
 		/* Make sure the height suits the 3 column (resp. not-editable) format; the 2 column format can easily fill space between the lists */
 		this->smallest_y = ComputeMaxSize(min_acs_height, this->smallest_y + this->resize_y - 1, this->resize_y);
diff --git a/src/widget.cpp b/src/widget.cpp
--- a/src/widget.cpp
+++ b/src/widget.cpp
@@ -1239,10 +1239,10 @@ void NWidgetStacked::SetupSmallestSize(W
 
 		this->smallest_x = std::max(this->smallest_x, child_wid->smallest_x + child_wid->padding.Horizontal());
 		this->smallest_y = std::max(this->smallest_y, child_wid->smallest_y + child_wid->padding.Vertical());
-		this->fill_x = LeastCommonMultiple(this->fill_x, child_wid->fill_x);
-		this->fill_y = LeastCommonMultiple(this->fill_y, child_wid->fill_y);
-		this->resize_x = LeastCommonMultiple(this->resize_x, child_wid->resize_x);
-		this->resize_y = LeastCommonMultiple(this->resize_y, child_wid->resize_y);
+		this->fill_x = std::lcm(this->fill_x, child_wid->fill_x);
+		this->fill_y = std::lcm(this->fill_y, child_wid->fill_y);
+		this->resize_x = std::lcm(this->resize_x, child_wid->resize_x);
+		this->resize_y = std::lcm(this->resize_y, child_wid->resize_y);
 	}
 }
 
@@ -1409,12 +1409,12 @@ void NWidgetHorizontal::SetupSmallestSiz
 		if (child_wid->fill_x > 0) {
 			if (this->fill_x == 0 || this->fill_x > child_wid->fill_x) this->fill_x = child_wid->fill_x;
 		}
-		this->fill_y = LeastCommonMultiple(this->fill_y, child_wid->fill_y);
+		this->fill_y = std::lcm(this->fill_y, child_wid->fill_y);
 
 		if (child_wid->resize_x > 0) {
 			if (this->resize_x == 0 || this->resize_x > child_wid->resize_x) this->resize_x = child_wid->resize_x;
 		}
-		this->resize_y = LeastCommonMultiple(this->resize_y, child_wid->resize_y);
+		this->resize_y = std::lcm(this->resize_y, child_wid->resize_y);
 	}
 	if (this->fill_x == 0 && this->pip_ratio_pre + this->pip_ratio_inter + this->pip_ratio_post > 0) this->fill_x = 1;
 	/* 4. Increase by required PIP space. */
@@ -1598,12 +1598,12 @@ void NWidgetVertical::SetupSmallestSize(
 		if (child_wid->fill_y > 0) {
 			if (this->fill_y == 0 || this->fill_y > child_wid->fill_y) this->fill_y = child_wid->fill_y;
 		}
-		this->fill_x = LeastCommonMultiple(this->fill_x, child_wid->fill_x);
+		this->fill_x = std::lcm(this->fill_x, child_wid->fill_x);
 
 		if (child_wid->resize_y > 0) {
 			if (this->resize_y == 0 || this->resize_y > child_wid->resize_y) this->resize_y = child_wid->resize_y;
 		}
-		this->resize_x = LeastCommonMultiple(this->resize_x, child_wid->resize_x);
+		this->resize_x = std::lcm(this->resize_x, child_wid->resize_x);
 	}
 	if (this->fill_y == 0 && this->pip_ratio_pre + this->pip_ratio_inter + this->pip_ratio_post > 0) this->fill_y = 1;
 	/* 4. Increase by required PIP space. */