diff --git a/src/jack.h b/src/jack.h
index 90d4e51..0b06dd9 100644
--- a/src/jack.h
+++ b/src/jack.h
@@ -60,25 +60,35 @@ public:
 		return m_recording;
 	}
 
-	float LoopLength(int loop)
+	float LoopLength(int loop) const
 	{
 		return (float)m_loops[loop].Length() / m_sample_rate;
 	}
 
-	float LoopPosition(int loop)
+	float LoopPosition(int loop) const
 	{
 		return (float)m_loops[loop].Position() / m_sample_rate;
 	}
 
-	LoopState GetLoopState(int loop)
+	LoopState GetLoopState(int loop) const
 	{
 		return m_loops[loop].State();
 	}
 
-	bool LoopLooping(int loop)
+	bool LoopLooping(int loop) const
 	{
 		return m_loops[loop].Looping();
 	}
+
+	void SetTempo(int loop, float tempo)
+	{
+		m_loops[loop].SetTempo(tempo);
+	}
+
+	float GetTempo(int loop) const
+	{
+		return m_loops[loop].Tempo();
+	}
 };
 
 #endif /* JACK_H */
diff --git a/src/loop.cpp b/src/loop.cpp
index bbfa75c..77713ab 100644
--- a/src/loop.cpp
+++ b/src/loop.cpp
@@ -6,6 +6,7 @@ Loop::Loop()
 {
 	m_length = 0;
 	m_position = 0;
+	m_tempo = 1.0;
 	m_state = LS_IDLE;
 }
 
@@ -40,9 +41,9 @@ void Loop::PlayFrame(void *port_buffer, jack_nframes_t frame)
 		jack_midi_event_write(port_buffer, frame, event.buffer, event.size);
 	}
 
-	m_position++;
+	m_position += m_tempo;
 
-	if (m_position == m_length) {
+	if (m_position >= m_length) {
 		if (!m_loop) {
 			m_state = LS_IDLE;
 		}
diff --git a/src/loop.h b/src/loop.h
index e20c527..5ce84f8 100644
--- a/src/loop.h
+++ b/src/loop.h
@@ -23,9 +23,10 @@ typedef std::list<Event> EventList;
 class Loop {
 private:
 	jack_nframes_t m_length;   ///< Length of loop, in samples.
-	jack_nframes_t m_position; ///< Current position of loop, in samples.
+	float          m_position; ///< Current position of loop, in samples.
 	LoopState      m_state;
 	bool           m_loop;
+	float          m_tempo;
 
 	EventList           m_events;
 	EventList::iterator m_iterator;
@@ -55,14 +56,24 @@ public:
 		return m_state;
 	}
 
+	void SetTempo(float tempo)
+	{
+		m_tempo = tempo;
+	}
+
+	float Tempo() const
+	{
+		return m_tempo;
+	}
+
 	jack_nframes_t Length() const
 	{
-		return m_length;
+		return m_length / m_tempo;
 	}
 
 	jack_nframes_t Position() const
 	{
-		return m_position;
+		return m_position / m_tempo;
 	}
 
 	bool Looping() const
diff --git a/src/ui.cpp b/src/ui.cpp
index c387df6..fc93b84 100644
--- a/src/ui.cpp
+++ b/src/ui.cpp
@@ -154,7 +154,7 @@ bool UI::Run(Jack &j)
 		bkgdset(color_map[0]);
 		attrset(color_map[0]);
 
-		snprintf(buf, sizeof buf, " [ ] %2d: Position: %0.2f beats (%0.2fs) Length: %0.2f beats (%0.2fs)", i, m_bpm * j.LoopPosition(i) / 60.0, j.LoopPosition(i), m_bpm * j.LoopLength(i) / 60.0, j.LoopLength(i));
+		snprintf(buf, sizeof buf, " [ ] %2d: Position: %0.2f beats (%0.2fs) Length: %0.2f beats (%0.2fs) Tempo: %0.1f%%", i, m_bpm * j.LoopPosition(i) / 60.0, j.LoopPosition(i), m_bpm * j.LoopLength(i) / 60.0, j.LoopLength(i), j.GetTempo(i) * 100);
 		mvaddstr(i + y_offs, 0, buf);
 		clrtoeol();
 
@@ -282,6 +282,18 @@ bool UI::Run(Jack &j)
 			}
 			break;
 
+		case KEY_LEFT:
+			if (m_edit_mode == EM_LOOPS) {
+				j.SetTempo(m_loop, j.GetTempo(m_loop) - 0.001);
+			}
+			break;
+
+		case KEY_RIGHT:
+			if (m_edit_mode == EM_LOOPS) {
+				j.SetTempo(m_loop, j.GetTempo(m_loop) + 0.001);
+			}
+			break;
+
 		case KEY_BACKSPACE:
 			if (m_edit_mode == EM_BPM) {
 				m_bpm /= 10;