diff --git a/app/src/main/java/uk/org/openseizuredetector/FragmentCommon.java b/app/src/main/java/uk/org/openseizuredetector/FragmentCommon.java
index 3fefb1d..57c0785 100644
--- a/app/src/main/java/uk/org/openseizuredetector/FragmentCommon.java
+++ b/app/src/main/java/uk/org/openseizuredetector/FragmentCommon.java
@@ -93,6 +93,13 @@ public class FragmentCommon extends FragmentOsdBaseClass {
                 tv.setBackgroundColor(okColour);
                 tv.setTextColor(okTextColour);
 
+                tv = (TextView) mRootView.findViewById(R.id.data_time_tv);
+                tv.setText("Time =" + mConnection.mSdServer.mSdData.dataTime.format("%H:%M:%S")
+                        + "  (" + String.format("%.1f s)",mConnection.mSdServer.mSdData.timeDiff));
+                tv.setBackgroundColor(okColour);
+                tv.setTextColor(okTextColour);
+
+
                 tv = (TextView) mRootView.findViewById(R.id.alarmTv);
                 if ((mConnection.mSdServer.mSdData.alarmState == 0)
                         && !mConnection.mSdServer.mSdData.alarmStanding
diff --git a/app/src/main/java/uk/org/openseizuredetector/SdData.java b/app/src/main/java/uk/org/openseizuredetector/SdData.java
index ac41a10..8eaf1ed 100644
--- a/app/src/main/java/uk/org/openseizuredetector/SdData.java
+++ b/app/src/main/java/uk/org/openseizuredetector/SdData.java
@@ -105,6 +105,7 @@ public class SdData implements Parcelable {
 
     /* Analysis results */
     public Time dataTime = null;
+    public float timeDiff = 0f;
     public long alarmState;
     public String alarmCause = "";
     public boolean alarmStanding = false;
@@ -136,6 +137,7 @@ public class SdData implements Parcelable {
         rawData = new double[N_RAW_DATA];
         rawData3D = new double[N_RAW_DATA * 3];
         dataTime = new Time(Time.getCurrentTimezone());
+        timeDiff = 0f;
     }
 
     /*
@@ -153,6 +155,10 @@ public class SdData implements Parcelable {
             //cal.setTime(sdf.parse(jo.optString("dataTimeStr")));
             //dataTime = cal.getTime();
             // FIXME - this doesn't work!!!
+            Time tnow = new Time();
+            tnow.setToNow();
+            timeDiff = (tnow.toMillis(false)
+                    - dataTime.toMillis(false))/1000f;
             dataTime.setToNow();
             Log.v(TAG, "fromJSON(): dataTime = " + dataTime.toString());
             maxVal = jo.optInt("maxVal");
diff --git a/app/src/main/java/uk/org/openseizuredetector/SdDataSource.java b/app/src/main/java/uk/org/openseizuredetector/SdDataSource.java
index c9c8073..971e98b 100644
--- a/app/src/main/java/uk/org/openseizuredetector/SdDataSource.java
+++ b/app/src/main/java/uk/org/openseizuredetector/SdDataSource.java
@@ -504,6 +504,12 @@ public abstract class SdDataSource {
             mDataStatusTime.setToNow();
             mSdData.specPower = (long) specPower / ACCEL_SCALE_FACTOR;
             mSdData.roiPower = (long) roiPower / ACCEL_SCALE_FACTOR;
+            Time tnow = new Time();
+            tnow.setToNow();
+            mSdData.timeDiff = (tnow.toMillis(false)
+                    - mSdData.dataTime.toMillis(false))/1000f;
+            mSdData.dataTime.setToNow();
+
             mSdData.dataTime.setToNow();
             mSdData.maxVal = 0;   // not used
             mSdData.maxFreq = 0;  // not used
diff --git a/app/src/main/res/layout/fragment_common.xml b/app/src/main/res/layout/fragment_common.xml
index 4556bc4..54ef7b0 100644
--- a/app/src/main/res/layout/fragment_common.xml
+++ b/app/src/main/res/layout/fragment_common.xml
@@ -25,6 +25,12 @@
             android:layout_height="wrap_content"
             android:text="---" />
 
+        <TextView
+            android:id="@+id/data_time_tv"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="---" />
+
         <LinearLayout
             android:id="@+id/statusLayout"
             android:layout_width="fill_parent"