diff --git a/src/components/simulation-chart.tsx b/src/components/simulation-chart.tsx
index 94eee0a..f886f01 100644
--- a/src/components/simulation-chart.tsx
+++ b/src/components/simulation-chart.tsx
@@ -274,7 +274,7 @@ const SimulationChart = React.memo(({
         // User set yAxisMax explicitly
         // Add padding to dataMax and use the higher of manual or (dataMax + padding)
         const range = dataMax - dataMin;
-        const padding = range * 0.1;
+        const padding = range * 0.05;
         const dataMaxWithPadding = dataMax + padding;
         // Use manual max only if it's higher than dataMax + padding
         domainMax = Math.max(numMax, dataMaxWithPadding);
@@ -283,9 +283,9 @@ const SimulationChart = React.memo(({
         domainMax = numMax;
       }
     } else if (dataMax !== -Infinity) { // data exists
-      // Auto mode: add 10% padding above
+      // Auto mode: add 5% padding above
       const range = dataMax - dataMin;
-      const padding = range * 0.1;
+      const padding = range * 0.05;
       domainMax = dataMax + padding;
     } else { // no data
       domainMax = 100;
@@ -544,7 +544,7 @@ const SimulationChart = React.memo(({
               domain={yAxisDomain as any}
               axisLine={{ stroke: isDarkTheme ? '#ccc' : '#666' }}
               tick={<YAxisTick />}
-              allowDecimals={true}
+              allowDecimals={false}
               allowDataOverflow={false}
             />
             <RechartsTooltip