diff --git a/test/s3vectors/s3vectors_test.py b/test/s3vectors/s3vectors_test.py
index e8138e7e35..53ce40c4dd 100644
--- a/test/s3vectors/s3vectors_test.py
+++ b/test/s3vectors/s3vectors_test.py
@@ -58,7 +58,7 @@ def test_vector_lifecycle(vectors):
     assert [h["key"] for h in hits] == ["a", "c"]
     distances = {h["key"]: h["distance"] for h in hits}
     assert distances["a"] == pytest.approx(0.0, abs=1e-6)
-    assert distances["c"] == pytest.approx(0.02, abs=1e-4)
+    assert distances["c"] == pytest.approx(0.02 ** 0.5, abs=1e-4)
     assert all(h["metadata"]["color"] == "red" for h in hits)
 
     vectors.delete_vectors(vectorBucketName=BUCKET, indexName=INDEX, keys=["b"])
@@ -223,6 +223,13 @@ def test_filter_arrays(vectors, index):
     assert matches({"$nin": [1, "2.5"]}) == ["flag", "scalar", "space"]
 
 
+def test_euclidean_distance(vectors, index):
+    vectors.put_vectors(**index, vectors=[{"key": "p", "data": {"float32": [3, 4, 0, 0]}}])
+    result = vectors.query_vectors(**index, queryVector={"float32": [0, 0, 0, 0]}, topK=1, returnDistance=True)
+    assert result["distanceMetric"] == "euclidean"
+    assert result["vectors"][0]["distance"] == pytest.approx(5.0)
+
+
 def test_cosine_metric(vectors):
     bucket = "cosine-" + uuid.uuid4().hex[:16]
     vectors.create_vector_bucket(vectorBucketName=bucket)
diff --git a/weed/s3api/s3vectors/distance_metric_test.go b/weed/s3api/s3vectors/distance_metric_test.go
index e3a149778e..502216bb8c 100644
--- a/weed/s3api/s3vectors/distance_metric_test.go
+++ b/weed/s3api/s3vectors/distance_metric_test.go
@@ -3,6 +3,7 @@ package s3vectors
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"testing"
 
@@ -86,3 +87,54 @@ func TestIndexFromRecordLowercasesMetric(t *testing.T) {
 		}
 	}
 }
+
+type distancesFake struct {
+	*fakeVectors
+	distances []float32
+}
+
+func (f distancesFake) QueryVectors(ctx context.Context, req *vector_pb.QueryVectorsRequest, opts ...grpc.CallOption) (*vector_pb.QueryVectorsResponse, error) {
+	resp := &vector_pb.QueryVectorsResponse{}
+	for i, d := range f.distances {
+		resp.Vectors = append(resp.Vectors, &vector_pb.QueryResult{Key: fmt.Sprint(i), Distance: d})
+	}
+	return resp, nil
+}
+
+// The engine returns Lance's squared L2 distance; a euclidean index reports
+// its square root, the other metrics their engine value.
+func TestQueryVectorsReportsEuclideanDistance(t *testing.T) {
+	for metric, want := range map[string][]float32{
+		"euclidean":  {5, 0.5, 0},
+		"cosine":     {25, 0.25, -1e-7},
+		"dotproduct": {25, 0.25, -1e-7},
+	} {
+		fs := s3tablestest.Start(t)
+		engine := distancesFake{newFakeVectors(0), []float32{25, 0.25, -1e-7}}
+		s := NewServer(s3tables.NewManagerClient(fs.Client), allowAllAuth{}, engine)
+		if w := postJSON(t, s.handleCreateVectorBucket, &CreateVectorBucketRequest{VectorBucketName: "vec-bucket"}); w.Code != http.StatusOK {
+			t.Fatalf("create bucket: %d %s", w.Code, w.Body.String())
+		}
+		if w := postJSON(t, s.handleCreateIndex, &CreateIndexRequest{
+			VectorBucketName: "vec-bucket", IndexName: "idx", DataType: "float32", Dimension: 2, DistanceMetric: metric,
+		}); w.Code != http.StatusOK {
+			t.Fatalf("create index: %d %s", w.Code, w.Body.String())
+		}
+		w := postJSON(t, s.handleQueryVectors, &QueryVectorsRequest{
+			VectorBucketName: "vec-bucket", IndexName: "idx",
+			QueryVector: &QueryVector{Float32: []float32{1, 0}}, TopK: 3, ReturnDistance: true,
+		})
+		var query QueryVectorsResponse
+		if err := json.Unmarshal(w.Body.Bytes(), &query); err != nil || len(query.Vectors) != len(want) {
+			t.Fatalf("%s QueryVectors: %d %s", metric, w.Code, w.Body.String())
+		}
+		for i, v := range query.Vectors {
+			if v.Distance == nil {
+				t.Fatalf("%s hit %d has no distance", metric, i)
+			}
+			if *v.Distance != want[i] {
+				t.Fatalf("%s hit %d distance %v, want %v", metric, i, *v.Distance, want[i])
+			}
+		}
+	}
+}
diff --git a/weed/s3api/s3vectors/handlers.go b/weed/s3api/s3vectors/handlers.go
index 2dbe75eab3..593e4237ce 100644
--- a/weed/s3api/s3vectors/handlers.go
+++ b/weed/s3api/s3vectors/handlers.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"math"
 	"net/http"
 	"strconv"
 	"strings"
@@ -1938,7 +1939,12 @@ func (s *Server) handleQueryVectors(w http.ResponseWriter, r *http.Request) {
 	for _, v := range resp.Vectors {
 		o := &QueryOutputVector{Key: v.Key}
 		if req.ReturnDistance {
-			o.Distance = &v.Distance
+			d := v.Distance
+			if metric == "euclidean" {
+				// Lance's L2 distance is the square of the Euclidean distance.
+				d = float32(math.Sqrt(math.Max(0, float64(d))))
+			}
+			o.Distance = &d
 		}
 		if req.ReturnMetadata {
 			o.Metadata = structToMap(v.Metadata)