diff --git a/evoGUI.lua b/evoGUI.lua
index 72b9c6b..3ed5aec 100644
--- a/evoGUI.lua
+++ b/evoGUI.lua
@@ -14,6 +14,12 @@ if not evogui.on_click then evogui.on_click = {} end
 local EXPECTED_VERSION = "{{VERSION}}"
 
 
+function evogui.format_number(n) -- credit http://richard.warburton.it
+    local left,num,right = string.match(n,'^([^%d]*%d)(%d*)(.-)$')
+    return left..(num:reverse():gsub('(%d%d%d)','%1,'):reverse())..right
+end
+
+
 function evogui.update_gui()
     if not global.settings then global.settings = {} end
     if not global.settings.update_delay then global.settings.update_delay = 60 end
diff --git a/value_sensors/kill_count.lua b/value_sensors/kill_count.lua
index 5bf2715..f59515d 100644
--- a/value_sensors/kill_count.lua
+++ b/value_sensors/kill_count.lua
@@ -67,17 +67,17 @@ function sensor:update_ui(owner)
 
     local biter_kills = {"sensor.kill_count.biter_fragment_single"}
     if biter_count ~= 1 then
-        biter_kills = {"sensor.kill_count.biter_fragment_multiple", biter_count}
+        biter_kills = {"sensor.kill_count.biter_fragment_multiple", evogui.format_number(biter_count)}
     end
 
     local spawner_kills = {"sensor.kill_count.spawner_fragment_single"}
     if spawner_count ~= 1 then
-        spawner_kills = {"sensor.kill_count.spawner_fragment_multiple", spawner_count}
+        spawner_kills = {"sensor.kill_count.spawner_fragment_multiple", evogui.format_number(spawner_count)}
     end
 
     local other_kills = {"sensor.kill_count.other_fragment_single"}
     if other_count ~= 1 then
-        other_kills = {"sensor.kill_count.other_fragment_multiple", other_count}
+        other_kills = {"sensor.kill_count.other_fragment_multiple", evogui.format_number(other_count)}
     end
 
     owner[self.name].caption = {self.format_key, biter_kills, spawner_kills, other_kills}