diff --git a/implot.cpp b/implot.cpp
index 231dd3c..49d132f 100644
--- a/implot.cpp
+++ b/implot.cpp
@@ -854,7 +854,9 @@ bool BeginPlot(const char* title, const char* x_label, const char* y_label, cons
     // BB AND HOVER -----------------------------------------------------------
 
     // frame
-    const ImVec2 frame_size = ImGui::CalcItemSize(size, 100, 100);
+    const float default_w = ImGui::CalcItemWidth();
+    const float default_h = default_w * 0.75f;
+    const ImVec2 frame_size = ImGui::CalcItemSize(size, default_w, default_w);
     gp.BB_Frame = ImRect(Window->DC.CursorPos, Window->DC.CursorPos + frame_size);
     ImGui::ItemSize(gp.BB_Frame);
     if (!ImGui::ItemAdd(gp.BB_Frame, 0, &gp.BB_Frame)) {
diff --git a/implot_demo.cpp b/implot_demo.cpp
index fdf1800..0e15d4c 100644
--- a/implot_demo.cpp
+++ b/implot_demo.cpp
@@ -152,7 +152,7 @@ void ShowDemoWindow(bool* p_open) {
             xs2[i] = i * 0.1f;
             ys2[i] = xs2[i] * xs2[i];
         }
-        if (ImPlot::BeginPlot("Line Plot", "x", "f(x)", ImVec2(-1,300))) {
+        if (ImPlot::BeginPlot("Line Plot", "x", "f(x)", ImVec2(0,0))) {
             ImPlot::PlotLine("sin(50*x)", xs1, ys1, 1001);
             ImPlot::PushStyleVar(ImPlotStyleVar_Marker, ImPlotMarker_Circle);
             ImPlot::PlotLine("x^2", xs2, ys2, 11);