diff --git a/src/dialog_resample.cpp b/src/dialog_resample.cpp
index 7575aaa31..bf616cb83 100644
--- a/src/dialog_resample.cpp
+++ b/src/dialog_resample.cpp
@@ -233,7 +233,7 @@ void DialogResample::UpdateButtons() {
 
 	auto source_ar = double(source_x->GetValue()) / source_y->GetValue();
 	auto dest_ar = double(dest_x->GetValue()) / dest_y->GetValue();
-	bool ar_changed = abs(source_ar - dest_ar) / dest_ar > .01;
+	bool ar_changed = std::abs(source_ar - dest_ar) / dest_ar > .01;
 
 	ar_mode->Enable(ar_changed);
 
diff --git a/src/dialog_video_properties.cpp b/src/dialog_video_properties.cpp
index 01b863344..90c407844 100644
--- a/src/dialog_video_properties.cpp
+++ b/src/dialog_video_properties.cpp
@@ -119,7 +119,7 @@ bool update_video_properties(AssFile *file, const AsyncVideoProvider *new_provid
 
 	auto sar = double(sx) / sy;
 	auto var = double(vx) / vy;
-	bool ar_changed = abs(sar - var) / var > .01;
+	bool ar_changed = std::abs(sar - var) / var > .01;
 
 	switch (OPT_GET("Video/Script Resolution Mismatch")->GetInt()) {
 	case MISMATCH_IGNORE: default:
diff --git a/src/resolution_resampler.cpp b/src/resolution_resampler.cpp
index 0f317161a..ee4e19f87 100644
--- a/src/resolution_resampler.cpp
+++ b/src/resolution_resampler.cpp
@@ -229,7 +229,7 @@ void ResampleResolution(AssFile *ass, ResampleSettings settings) {
 	bool border_horizontally = new_ar > old_ar;
 	// Don't convert aspect ratio if it's very close to correct
 	// (for reference, 848x480 <-> 1280x720 is .006)
-	if (abs(old_ar - new_ar) / new_ar > .01) {
+	if (std::abs(old_ar - new_ar) / new_ar > .01) {
 		switch (settings.ar_mode) {
 		case ResampleARMode::RemoveBorder:
 			border_horizontally = !border_horizontally;
@@ -247,7 +247,7 @@ void ResampleResolution(AssFile *ass, ResampleSettings settings) {
 				double(settings.source_x + settings.margin[LEFT] + settings.margin[RIGHT]) /
 				double(settings.source_y + settings.margin[TOP] + settings.margin[BOTTOM]);
 
-			if (abs(old_ar - new_ar) / new_ar > .01)
+			if (std::abs(old_ar - new_ar) / new_ar > .01)
 				horizontal_stretch = new_ar / old_ar;
 			break;
 		}
diff --git a/src/vector2d.cpp b/src/vector2d.cpp
index d9ef5b9aa..7c06f9d99 100644
--- a/src/vector2d.cpp
+++ b/src/vector2d.cpp
@@ -57,7 +57,7 @@ Vector2D Vector2D::Unit() const {
 }
 
 Vector2D Vector2D::SingleAxis() const {
-	if (abs(x) < abs(y))
+	if (std::abs(x) < std::abs(y))
 		return Vector2D(0, y);
 	else
 		return Vector2D(x, 0);
diff --git a/src/visual_tool_scale.cpp b/src/visual_tool_scale.cpp
index 1a0a0a1de..045352048 100644
--- a/src/visual_tool_scale.cpp
+++ b/src/visual_tool_scale.cpp
@@ -92,7 +92,7 @@ void VisualToolScale::UpdateHold() {
 	if (shift_down)
 		delta = delta.SingleAxis();
 	if (alt_down) {
-		if (abs(delta.X()) > abs(delta.Y()))
+		if (std::abs(delta.X()) > std::abs(delta.Y()))
 			delta = Vector2D(delta.X(), delta.X() * (initial_scale.Y() / initial_scale.X()));
 		else
 			delta = Vector2D(delta.Y() * (initial_scale.X() / initial_scale.Y()), delta.Y());