diff --git a/bare-metrics-gui/src/graph.rs b/bare-metrics-gui/src/graph.rs
index 7f7f941..312ec33 100644
--- a/bare-metrics-gui/src/graph.rs
+++ b/bare-metrics-gui/src/graph.rs
@@ -40,11 +40,12 @@ pub struct HeatmapRect {
     density: f64,
 }
 
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug)]
 pub struct HistogramWindow {
     pub heatmap: Vec<HeatmapRect>,
     pub min_density: f64,
     pub max_density: f64,
+    pub y_axis: RangeInclusive<f64>,
 }
 
 #[derive(Clone, Debug, Default)]
@@ -62,12 +63,15 @@ impl UnsummarisedHistogramWindow {
 
         let mut min_density = f64::INFINITY;
         let mut max_density = f64::NEG_INFINITY;
+        let mut min_val = f64::INFINITY;
+        let mut max_val = f64::NEG_INFINITY;
 
         for (xa, xb, hist) in self.map.iter() {
-            let min_val = hist.min();
-            let max_val = hist.max();
+            let min_this_slice = hist.min();
+            min_val = min_val.min(min_this_slice as f64);
+            max_val = max_val.max(hist.max() as f64);
 
-            let mut prev = min_val;
+            let mut prev = min_this_slice;
             for q in (1..=10).map(|i| i as f64 * 0.1) {
                 // TODO improve this. It's going to be a bit off because of the way that
                 // numbers can be 'equivalent' etc ...
@@ -95,17 +99,21 @@ impl UnsummarisedHistogramWindow {
             //debug!("hist min {:?} max {:?}", hist.min(), hist.max());
         }
 
+        let y_axis = min_val..=max_val;
+        debug!("yaxis {:?}", y_axis);
         HistogramWindow {
             heatmap,
             min_density,
             max_density,
+            y_axis,
         }
     }
 }
 
-#[derive(Clone, Debug, Default)]
+#[derive(Clone, Debug)]
 pub struct ScalarWindow {
-    points: Vec<(UnixTimestampMilliseconds, f64)>,
+    pub points: Vec<(UnixTimestampMilliseconds, f64)>,
+    pub y_axis: RangeInclusive<f64>,
 }
 
 pub struct MetricsLogReadingRequester {
@@ -392,12 +400,22 @@ impl<R: Read + Seek> MetricsLogReaderManager<R> {
                         histograms.insert(*metric_id, Default::default());
                     }
                     MetricKind::Gauge => {
-                        metrics_window.gauges.insert(*metric_id, Default::default());
+                        metrics_window.gauges.insert(
+                            *metric_id,
+                            ScalarWindow {
+                                points: vec![],
+                                y_axis: 0.0..=0.0,
+                            },
+                        );
                     }
                     MetricKind::Counter => {
-                        metrics_window
-                            .counters
-                            .insert(*metric_id, Default::default());
+                        metrics_window.counters.insert(
+                            *metric_id,
+                            ScalarWindow {
+                                points: vec![],
+                                y_axis: 0.0..=0.0,
+                            },
+                        );
                     }
                 }
             }
@@ -707,7 +725,18 @@ impl Graph {
 
             // This range is reversed because screen coordinates go down, but we'd like them to go
             // up since this is more of a mathematical graph.
-            let y_axis = 300.0..=0.0;
+            let y_axis = if let Some(histogram) = current_window.histograms.get(&metric_id) {
+                histogram.y_axis.clone().into_inner()
+            } else if let Some(scalar) = current_window
+                .counters
+                .get(&metric_id)
+                .or_else(|| current_window.gauges.get(&metric_id))
+            {
+                scalar.y_axis.clone().into_inner()
+            } else {
+                (0.0, 10.0)
+            };
+            let y_axis = (y_axis.1)..=(y_axis.0);
 
             // let display_transform =
             //     emath::RectTransform::from_to(Rect::from_x_y_ranges(x_axis, y_axis), display_rect);