diff --git a/src/lib.rs b/src/lib.rs
index 28a0314a..8e5af543 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -208,10 +208,10 @@ fn manysearch<P: AsRef<Path>>(
     };
     let thrd = std::thread::spawn(move || {
         let mut writer = BufWriter::new(out);
-        writeln!(&mut writer, "query,query_md5,match,match_md5,containment").unwrap();
-        for (query, query_md5, m, m_md5, overlap) in recv.into_iter() {
-            writeln!(&mut writer, "\"{}\",{},\"{}\",{},{}",
-                     query, query_md5, m, m_md5, overlap).ok();
+        writeln!(&mut writer, "query_name,query_md5,match_name,match_md5,containment,jaccard,intersect_hashes").unwrap();
+        for (query, query_md5, m, m_md5, cont, jaccard, overlap) in recv.into_iter() {
+            writeln!(&mut writer, "\"{}\",{},\"{}\",{},{},{},{}",
+                     query, query_md5, m, m_md5, cont, jaccard, overlap).ok();
         }
     });
 
@@ -241,14 +241,21 @@ fn manysearch<P: AsRef<Path>>(
                     // search for matches & save containment.
                     for q in queries.iter() {
                         let overlap = q.minhash.count_common(&search_sm.minhash, false).unwrap() as f64;
-                        let size = q.minhash.size() as f64;
+                        let query_size = q.minhash.size() as f64;
 
-                        let containment = overlap / size;
+                        let mut merged = q.minhash.clone();
+                        merged.merge(&search_sm.minhash).ok();
+                        let total_size = merged.size() as f64;
+
+                        let containment = overlap / query_size;
+                        let jaccard = overlap / total_size;
                         if containment > threshold {
                             results.push((q.name.clone(),
                                           q.md5sum.clone(),
                                           search_sm.name.clone(),
                                           search_sm.md5sum.clone(),
+                                          containment,
+                                          jaccard,
                                           overlap))
                         }
                     }
diff --git a/src/python/tests/test-data/1.combined.sig.gz b/src/python/tests/test-data/1.combined.sig.gz
index 0d039fa7..97d0e1cd 100644
Binary files a/src/python/tests/test-data/1.combined.sig.gz and b/src/python/tests/test-data/1.combined.sig.gz differ
diff --git a/src/python/tests/test_search.py b/src/python/tests/test_search.py
index 6526948a..17fe36e7 100644
--- a/src/python/tests/test_search.py
+++ b/src/python/tests/test_search.py
@@ -45,6 +45,35 @@ def test_simple(runtmp):
     df = pandas.read_csv(output)
     assert len(df) == 5
 
+    dd = df.to_dict(orient='index')
+    print(dd)
+
+    for idx, row in dd.items():
+        # identical?
+        if row['query_md5'] == row['match_md5']:
+            assert row['match_name'] == row['query_name']
+            assert float(row['containment'] == 1.0)
+            assert float(row['jaccard'] == 1.0)
+        else:
+            # confirm hand-checked numbers
+            q = row['query_name'].split()[0]
+            m = row['match_name'].split()[0]
+            jaccard = float(row['jaccard'])
+            cont = float(row['containment'])
+            intersect_hashes = int(row['intersect_hashes'])
+
+            jaccard = round(jaccard, 4)
+            cont = round(cont, 4)
+            print(q, m, f"{jaccard:.04}", f"{cont:.04}")
+
+            if q == 'NC_011665.1' and m == 'NC_009661.1':
+                assert jaccard == 0.3207
+                assert cont == 0.4828
+
+            if q == 'NC_009661.1' and m == 'NC_011665.1':
+                assert jaccard == 0.3207
+                assert cont == 0.4885
+
 
 def test_simple_threshold(runtmp):
     # test with a simple threshold => only 3 results