diff --git a/s-pipes-core/src/main/java/cz/cvut/spipes/function/time/Duration.java b/s-pipes-core/src/main/java/cz/cvut/spipes/function/time/Duration.java
new file mode 100644
index 00000000..76946d4a
--- /dev/null
+++ b/s-pipes-core/src/main/java/cz/cvut/spipes/function/time/Duration.java
@@ -0,0 +1,52 @@
+package cz.cvut.spipes.function.time;
+
+import cz.cvut.spipes.constants.KBSS_TIMEF;
+import cz.cvut.spipes.function.ValueFunction;
+import org.apache.jena.datatypes.xsd.XSDDatatype;
+import org.apache.jena.graph.Node;
+import org.apache.jena.graph.NodeFactory;
+import org.apache.jena.sparql.expr.NodeValue;
+import org.apache.jena.sparql.function.FunctionEnv;
+import org.topbraid.spin.arq.AbstractFunction2;
+
+import javax.xml.bind.DatatypeConverter;
+import java.util.Calendar;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Computes difference between two xsd:dateTime values in milliseconds and returns xsd:long datatype
+ */
+public class Duration extends AbstractFunction2 implements ValueFunction {
+
+    private static final String TYPE_IRI = KBSS_TIMEF.getURI() + "add-days";
+
+    @Override
+    public String getTypeURI() {
+        return TYPE_IRI;
+    }
+
+    @Override
+    protected NodeValue exec(Node t2, Node t1, FunctionEnv functionEnv) {
+        Calendar start = parseNodeToCalendar(t1);
+        Calendar end = parseNodeToCalendar(t2);
+
+        long duration = end.getTimeInMillis()-start.getTimeInMillis();
+        Node node = NodeFactory.createLiteralByValue(duration, XSDDatatype.XSDlong);
+        return NodeValue.makeNode(node);
+    }
+
+    private Calendar parseNodeToCalendar(Node x){
+        return DatatypeConverter.parseDateTime(extractDateTimePart(x.getLiteral().toString()));
+    }
+
+    private static String extractDateTimePart(String rdfLiteral) {
+        String dateTimePattern = "^(.*?)(?:\\^\\^.*|$)";
+        Pattern pattern = Pattern.compile(dateTimePattern);
+        Matcher matcher = pattern.matcher(rdfLiteral);
+
+        if (matcher.find())return matcher.group(1);
+        return null;
+    }
+
+}
diff --git a/s-pipes-core/src/test/java/cz/cvut/spipes/function/time/DurationTest.java b/s-pipes-core/src/test/java/cz/cvut/spipes/function/time/DurationTest.java
new file mode 100644
index 00000000..82dff2f6
--- /dev/null
+++ b/s-pipes-core/src/test/java/cz/cvut/spipes/function/time/DurationTest.java
@@ -0,0 +1,60 @@
+package cz.cvut.spipes.function.time;
+
+import org.apache.jena.datatypes.RDFDatatype;
+import org.apache.jena.datatypes.xsd.XSDDatatype;
+import org.apache.jena.graph.Node;
+import org.apache.jena.sparql.expr.NodeValue;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class DurationTest {
+
+    @Test
+    public void execSimple() {
+
+        Duration duration = new Duration();
+        Node t1 = getDateTimeNode("2023-08-21T13:00:00.100").asNode();
+        Node t2 = getDateTimeNode("2023-08-21T13:00:00.250").asNode();
+
+        NodeValue durationInMS = duration.exec(t2,t1,null);
+        long expected = 150;
+        assertEquals(expected,durationInMS.getInteger().intValue());
+    }
+
+    @Test
+    public void execT2IsEarlierThenT1() {
+
+        Duration duration = new Duration();
+        Node t1 = getDateTimeNode("2023-08-21T13:20:00").asNode();
+        Node t2 = getDateTimeNode("2023-08-21T13:00:00").asNode();
+
+        NodeValue durationInMS = duration.exec(t2,t1,null);
+        long expected = -1200000;
+        assertEquals(expected,durationInMS.getInteger().intValue());
+    }
+
+    @Test
+    public void execTimeZoneFormat() {
+
+        Duration duration = new Duration();
+        Node t1 = getDateTimeNode("2023-08-21T15:30:00.100-05:00").asNode();
+        Node t2 = getDateTimeNode("2023-08-21T14:30:05.600-06:00").asNode();
+
+        NodeValue durationInMS = duration.exec(t2,t1,null);
+        long expected = 5500;
+        assertEquals(expected,durationInMS.getInteger().intValue());
+    }
+
+    private NodeValue getDateTimeNode(String dateTime){
+        return getNode(dateTime, XSDDatatype.XSDdateTime);
+    }
+
+    private NodeValue getNode(String time, RDFDatatype datatype) {
+        return NodeValue.makeNode(
+                time,
+                null,
+                datatype.getURI()
+        );
+    }
+}
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