diff --git a/app/src/main/java/info/nightscout/androidaps/data/Profile.java b/app/src/main/java/info/nightscout/androidaps/data/Profile.java
index 8d78ca19b6..0595c2f84d 100644
--- a/app/src/main/java/info/nightscout/androidaps/data/Profile.java
+++ b/app/src/main/java/info/nightscout/androidaps/data/Profile.java
@@ -23,6 +23,7 @@ import info.nightscout.androidaps.plugins.Overview.notifications.Notification;
 import info.nightscout.utils.DateUtil;
 import info.nightscout.utils.DecimalFormatter;
 import info.nightscout.utils.FabricPrivacy;
+import info.nightscout.utils.MidnightTime;
 
 public class Profile {
     private static Logger log = LoggerFactory.getLogger(Profile.class);
@@ -381,7 +382,7 @@ public class Profile {
     }
 
     public double getIsf() {
-        return getIsfTimeFromMidnight(secondsFromMidnight(System.currentTimeMillis()));
+        return getIsfTimeFromMidnight(secondsFromMidnight());
     }
 
     public double getIsf(long time) {
@@ -401,7 +402,7 @@ public class Profile {
     }
 
     public double getIc() {
-        return getIcTimeFromMidnight(secondsFromMidnight(System.currentTimeMillis()));
+        return getIcTimeFromMidnight(secondsFromMidnight());
     }
 
     public double getIc(long time) {
@@ -421,7 +422,7 @@ public class Profile {
     }
 
     public double getBasal() {
-        return getBasalTimeFromMidnight(secondsFromMidnight(System.currentTimeMillis()));
+        return getBasalTimeFromMidnight(secondsFromMidnight());
     }
 
     public double getBasal(long time) {
@@ -465,7 +466,7 @@ public class Profile {
     }
 
     public double getTarget() {
-        return getTarget(secondsFromMidnight(System.currentTimeMillis()));
+        return getTarget(secondsFromMidnight());
     }
 
     protected double getTarget(int timeAsSeconds) {
@@ -473,7 +474,7 @@ public class Profile {
     }
 
     public double getTargetLow() {
-        return getTargetLowTimeFromMidnight(secondsFromMidnight(System.currentTimeMillis()));
+        return getTargetLowTimeFromMidnight(secondsFromMidnight());
     }
 
     public double getTargetLow(long time) {
@@ -487,7 +488,7 @@ public class Profile {
     }
 
     public double getTargetHigh() {
-        return getTargetHighTimeFromMidnight(secondsFromMidnight(System.currentTimeMillis()));
+        return getTargetHighTimeFromMidnight(secondsFromMidnight());
     }
 
     public double getTargetHigh(long time) {
@@ -518,24 +519,13 @@ public class Profile {
     }
 
     public static int secondsFromMidnight() {
-        Calendar c = Calendar.getInstance();
-        long now = c.getTimeInMillis();
-        c.set(Calendar.HOUR_OF_DAY, 0);
-        c.set(Calendar.MINUTE, 0);
-        c.set(Calendar.SECOND, 0);
-        c.set(Calendar.MILLISECOND, 0);
-        long passed = now - c.getTimeInMillis();
+        long passed = DateUtil.now() - MidnightTime.calc();
         return (int) (passed / 1000);
     }
 
     public static int secondsFromMidnight(long date) {
-        Calendar c = Calendar.getInstance();
-        c.setTimeInMillis(date);
-        c.set(Calendar.HOUR_OF_DAY, 0);
-        c.set(Calendar.MINUTE, 0);
-        c.set(Calendar.SECOND, 0);
-        c.set(Calendar.MILLISECOND, 0);
-        long passed = date - c.getTimeInMillis();
+        long midnight = MidnightTime.calc(date);
+        long passed = date - midnight;
         return (int) (passed / 1000);
     }
 
diff --git a/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobOref1Thread.java b/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobOref1Thread.java
index 049fb031bc..172a6bbc47 100644
--- a/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobOref1Thread.java
+++ b/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobOref1Thread.java
@@ -38,6 +38,8 @@ import info.nightscout.androidaps.plugins.Treatments.TreatmentsPlugin;
 import info.nightscout.utils.DateUtil;
 import info.nightscout.utils.DecimalFormatter;
 import info.nightscout.utils.FabricPrivacy;
+import info.nightscout.utils.MidnightTime;
+import info.nightscout.utils.Profiler;
 import info.nightscout.utils.SP;
 
 import static info.nightscout.utils.DateUtil.now;
@@ -75,6 +77,7 @@ public class IobCobOref1Thread extends Thread {
 
     @Override
     public final void run() {
+        long start = DateUtil.now();
         mWakeLock.acquire();
         try {
             if (L.isEnabled(L.AUTOSENS))
@@ -393,8 +396,11 @@ public class IobCobOref1Thread extends Thread {
         } finally {
             mWakeLock.release();
             MainApp.bus().post(new EventIobCalculationProgress(""));
-            if (L.isEnabled(L.AUTOSENS))
+            if (L.isEnabled(L.AUTOSENS)) {
                 log.debug("AUTOSENSDATA thread ended: " + from);
+                log.debug("Midnights: " + MidnightTime.log());
+            }
+            Profiler.log(log, "IobCobOref1Thread", start);
         }
     }
 
diff --git a/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobThread.java b/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobThread.java
index 7229532446..aa1f09592e 100644
--- a/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobThread.java
+++ b/app/src/main/java/info/nightscout/androidaps/plugins/IobCobCalculator/IobCobThread.java
@@ -38,6 +38,8 @@ import info.nightscout.androidaps.plugins.Treatments.TreatmentsPlugin;
 import info.nightscout.utils.DateUtil;
 import info.nightscout.utils.DecimalFormatter;
 import info.nightscout.utils.FabricPrivacy;
+import info.nightscout.utils.MidnightTime;
+import info.nightscout.utils.Profiler;
 import info.nightscout.utils.SP;
 
 import static info.nightscout.utils.DateUtil.now;
@@ -74,6 +76,7 @@ public class IobCobThread extends Thread {
 
     @Override
     public final void run() {
+        long start = DateUtil.now();
         mWakeLock.acquire();
         try {
             if (L.isEnabled(L.AUTOSENS))
@@ -320,8 +323,11 @@ public class IobCobThread extends Thread {
         } finally {
             mWakeLock.release();
             MainApp.bus().post(new EventIobCalculationProgress(""));
-            if (L.isEnabled(L.AUTOSENS))
+            if (L.isEnabled(L.AUTOSENS)) {
                 log.debug("AUTOSENSDATA thread ended: " + from);
+                log.debug("Midnights: " + MidnightTime.log());
+            }
+            Profiler.log(log, "IobCobThread", start);
         }
     }
 
diff --git a/app/src/main/java/info/nightscout/utils/MidnightTime.java b/app/src/main/java/info/nightscout/utils/MidnightTime.java
new file mode 100644
index 0000000000..523fe13826
--- /dev/null
+++ b/app/src/main/java/info/nightscout/utils/MidnightTime.java
@@ -0,0 +1,43 @@
+package info.nightscout.utils;
+
+import android.util.LongSparseArray;
+
+import java.util.Calendar;
+
+public class MidnightTime {
+    private static LongSparseArray times = new LongSparseArray();
+
+    private static long hits = 0;
+    private static long misses = 0;
+
+    public static long calc() {
+        Calendar c = Calendar.getInstance();
+        c.set(Calendar.HOUR_OF_DAY, 0);
+        c.set(Calendar.MINUTE, 0);
+        c.set(Calendar.SECOND, 0);
+        c.set(Calendar.MILLISECOND, 0);
+        return c.getTimeInMillis();
+    }
+
+    public static long calc(long time) {
+        Long m = (Long) times.get(time);
+        if (m != null) {
+            ++hits;
+            return m;
+        }
+        Calendar c = Calendar.getInstance();
+        c.setTimeInMillis(time);
+        c.set(Calendar.HOUR_OF_DAY, 0);
+        c.set(Calendar.MINUTE, 0);
+        c.set(Calendar.SECOND, 0);
+        c.set(Calendar.MILLISECOND, 0);
+        m = c.getTimeInMillis();
+        times.append(time, m);
+        ++misses;
+        return m;
+    }
+
+    public static String log() {
+        return "Hits: " + hits + " misses: " + misses + " stored: " + times.size();
+    }
+}