diff --git a/hibernate-core/src/main/java/org/hibernate/dialect/function/IntegralTimestampaddFunction.java b/hibernate-core/src/main/java/org/hibernate/dialect/function/IntegralTimestampaddFunction.java
index 154990cbf7..919f119eae 100644
--- a/hibernate-core/src/main/java/org/hibernate/dialect/function/IntegralTimestampaddFunction.java
+++ b/hibernate-core/src/main/java/org/hibernate/dialect/function/IntegralTimestampaddFunction.java
@@ -103,7 +103,7 @@ public class IntegralTimestampaddFunction
 
 	private Expression convertedArgument(DurationUnit field, TemporalUnit unit, Expression magnitude) {
 		final BasicValuedMapping expressionType = (BasicValuedMapping) magnitude.getExpressionType();
-		final String conversionFactor = field.getUnit().conversionFactor( unit, dialect );
+		final String conversionFactor = field.getUnit().conversionFactorFull( unit, dialect );
 		return conversionFactor.isEmpty()
 				? magnitude
 				: new BinaryArithmeticExpression(
diff --git a/hibernate-core/src/main/java/org/hibernate/query/sqm/TemporalUnit.java b/hibernate-core/src/main/java/org/hibernate/query/sqm/TemporalUnit.java
index d47c16d04c..b5aca3a272 100644
--- a/hibernate-core/src/main/java/org/hibernate/query/sqm/TemporalUnit.java
+++ b/hibernate-core/src/main/java/org/hibernate/query/sqm/TemporalUnit.java
@@ -197,6 +197,33 @@ public enum TemporalUnit {
 		}
 	}
 
+	public String conversionFactorFull(TemporalUnit unit, Dialect dialect) {
+
+		if ( unit == this ) {
+			//same unit, nothing to do
+			return "";
+		}
+
+		if ( unit.normalized() != normalized() ) {
+			throw new SemanticException("Illegal unit conversion " + this + " to " + unit);
+		}
+
+		long from = normalizationFactor( dialect );
+		long to = unit.normalizationFactor( dialect );
+		if ( from == to ) {
+			// the units represent the same amount of time
+			return "";
+		}
+		else {
+			// if from < to, then this unit represents a
+			// smaller amount of time than the given unit
+			// we are converting to (so we're going to
+			// need to use division)
+			return (from < to ? "/" : "*")
+					+ (from < to ? to / from : from / to);
+		}
+	}
+
 	/**
 	 * The conversion factor required to convert this
 	 * unit to its {@link #normalized()} unit.