diff --git a/app/src/main/java/net/pokeranalytics/android/calculus/Calculator.kt b/app/src/main/java/net/pokeranalytics/android/calculus/Calculator.kt
index 863ba2e3..c1a9ae52 100644
--- a/app/src/main/java/net/pokeranalytics/android/calculus/Calculator.kt
+++ b/app/src/main/java/net/pokeranalytics/android/calculus/Calculator.kt
@@ -177,20 +177,23 @@ class Calculator {
 
                 ))
 
+            val bbPer100Hands = bbSum / totalHands * 100
+
             // Standard Deviation
             if (options.shouldComputeStandardDeviation()) {
 
+                // Session
                 var stdSum: Double = 0.0
                 var stdBBper100HandsSum: Double = 0.0
-                sessions.forEach { s ->
-                    stdSum += Math.pow(s.value - average, 2.0)
-                    stdBBper100HandsSum += Math.pow(s.bbPer100Hands - hourlyRate, 2.0)
+                sessions.forEach { session ->
+                    stdSum += Math.pow(session.value - average, 2.0)
+                    stdBBper100HandsSum += Math.pow(session.bbPer100Hands - bbPer100Hands, 2.0)
                 }
                 val standardDeviation: Double = Math.sqrt(stdSum / sessions.size)
-                val standardDeviationBBper100Hands: Double = Math.sqrt(stdBBper100HandsSum / sessionSets.size)
+                val standardDeviationBBper100Hands: Double = Math.sqrt(stdBBper100HandsSum / sessions.size)
 
+                // Session Set
                 var hourlyStdSum: Double = 0.0
-
                 sessionSets.forEach { sg ->
                     hourlyStdSum += Math.pow(sg.hourlyRate - hourlyRate, 2.0)
                 }
diff --git a/app/src/main/java/net/pokeranalytics/android/calculus/Computable.kt b/app/src/main/java/net/pokeranalytics/android/calculus/Computable.kt
index 0f01a82a..d4aabc47 100644
--- a/app/src/main/java/net/pokeranalytics/android/calculus/Computable.kt
+++ b/app/src/main/java/net/pokeranalytics/android/calculus/Computable.kt
@@ -18,6 +18,8 @@ interface SessionInterface : Summable {
     var bbNetResult: Double
     var bigBlindSessionCount: Int // 0 or 1
     var buyin: Double
+    var bbPer100Hands: Double
+
 }
 
 /**
diff --git a/app/src/main/java/net/pokeranalytics/android/model/realm/Session.kt b/app/src/main/java/net/pokeranalytics/android/model/realm/Session.kt
index 95b2025b..298dc3dd 100644
--- a/app/src/main/java/net/pokeranalytics/android/model/realm/Session.kt
+++ b/app/src/main/java/net/pokeranalytics/android/model/realm/Session.kt
@@ -240,7 +240,7 @@ open class Session : RealmObject(), SessionInterface, Savable,
 		}
 
 	@Ignore
-	var bbPer100Hands: Double = 0.0
+	override var bbPer100Hands: Double = 0.0
 		get() {
 			return this.bbNetResult / this.estimatedHands * 100.0
 		}