diff --git a/libs/temporal/tempo.cc b/libs/temporal/tempo.cc
index d7874beb7a..09a922f52b 100644
--- a/libs/temporal/tempo.cc
+++ b/libs/temporal/tempo.cc
@@ -4768,6 +4768,20 @@ TempoMap::min_notes_per_minute() const
 	return npm;
 }
 
+timepos_t
+TempoMap::duration(TimeDomain td) const
+{
+	if (_points.empty()) {
+		return timepos_t::zero (td);
+	}
+
+	if (td == BeatTime) {
+		return timepos_t (_points.back().beats() + Beats (1, 0));
+	}
+
+	return timepos_t::from_superclock (_points.back().sclock() + 1);
+}
+
 #if 0
 void
 TempoMap::fix_legacy_session ()
diff --git a/libs/temporal/temporal/tempo.h b/libs/temporal/temporal/tempo.h
index 180c15da04..69d82c8c55 100644
--- a/libs/temporal/temporal/tempo.h
+++ b/libs/temporal/temporal/tempo.h
@@ -872,6 +872,8 @@ class /*LIBTEMPORAL_API*/ TempoMap : public PBD::StatefulDestructible
 	LIBTEMPORAL_API void shift (timepos_t const & at, BBT_Offset const & by);
 	LIBTEMPORAL_API void shift (timepos_t const & at, timecnt_t const & by);
 
+	LIBTEMPORAL_API timepos_t duration (TimeDomain) const;
+
   private:
 	template<typename TimeType, typename Comparator> TempoPoint const & _tempo_at (TimeType when, Comparator cmp) const {
 		assert (!_tempos.empty());