diff --git a/include/slurp.h b/include/slurp.h
index 92e37a9..7244516 100644
--- a/include/slurp.h
+++ b/include/slurp.h
@@ -31,6 +31,7 @@ struct slurp_state {
 	} colors;
 
 	uint32_t border_weight;
+	bool display_dimensions;
 
 	struct slurp_box result;
 };
diff --git a/main.c b/main.c
index cebe49c..7e29b8b 100644
--- a/main.c
+++ b/main.c
@@ -332,6 +332,7 @@ static const char usage[] =
 	"Usage: slurp [options...]\n"
 	"\n"
 	"  -h         Show help message and quit.\n"
+	"  -d         Display dimensions of selection.\n"
 	"  -b #rrggbb Set background color.\n"
 	"  -c #rrggbb Set border color.\n"
 	"  -s #rrggbb Set selection color.\n"
@@ -363,14 +364,18 @@ int main(int argc, char *argv[]) {
 			.selection = 0x00000000,
 		},
 		.border_weight = 2,
+		.display_dimensions = false,
 	};
 
 	int opt;
-	while ((opt = getopt(argc, argv, "hb:c:s:w:")) != -1) {
+	while ((opt = getopt(argc, argv, "hdb:c:s:w:")) != -1) {
 		switch (opt) {
 		case 'h':
 			printf("%s", usage);
 			return EXIT_SUCCESS;
+		case 'd':
+			state.display_dimensions = true;
+			break;
 		case 'b':
 			state.colors.background = parse_color(optarg);
 			break;
diff --git a/render.c b/render.c
index ef1445b..22e0350 100644
--- a/render.c
+++ b/render.c
@@ -46,5 +46,16 @@ void render(struct slurp_output *output) {
 		cairo_rectangle(cairo, x * scale, y * scale,
 			width * scale, height * scale);
 		cairo_stroke(cairo);
+
+		if (state->display_dimensions) {
+			cairo_select_font_face(cairo, "Sans", CAIRO_FONT_SLANT_NORMAL,
+				CAIRO_FONT_WEIGHT_NORMAL);
+			cairo_set_font_size(cairo, 14 * scale);
+			// buffer of 12 can hold selections up to 99999x99999
+			char dimensions[12];
+			snprintf(dimensions, sizeof(dimensions), "%ix%i", width, height);
+			cairo_move_to(cairo, (x + width + 10) * scale, (y + height + 20) * scale);
+			cairo_show_text(cairo, dimensions);
+		}
 	}
 }
diff --git a/slurp.1.scd b/slurp.1.scd
index f85410c..7df00c4 100644
--- a/slurp.1.scd
+++ b/slurp.1.scd
@@ -19,6 +19,9 @@ select, or click to cancel the selection.
 *-h*
 	Show help message and quit.
 
+*-d*
+	Display dimensions of selection.
+
 *-b* _color_
 	Set background color. See *COLORS* for more detail.