diff --git a/units/src/locktime/relative.rs b/units/src/locktime/relative.rs
index 5edafe01e..ca2fbe8af 100644
--- a/units/src/locktime/relative.rs
+++ b/units/src/locktime/relative.rs
@@ -307,6 +307,13 @@ mod tests {
         assert_eq!(NumberOf512Seconds::from_512_second_intervals(1).to_seconds(), 512);
     }
 
+    #[test]
+    fn from_512_second_intervals_roundtrip() {
+        let intervals = 100_u16;
+        let locktime = NumberOf512Seconds::from_512_second_intervals(intervals);
+        assert_eq!(locktime.to_512_second_intervals(), intervals);
+    }
+    
     #[test]
     fn from_seconds_ceil_success() {
         let actual = NumberOf512Seconds::from_seconds_ceil(100).unwrap();