diff --git a/bench/bench.go b/bench/bench.go
index 5e31508..99c1c24 100644
--- a/bench/bench.go
+++ b/bench/bench.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"sort"
 	"time"
 
 	"github.com/lightpanda-io/perf-fmt/git"
@@ -90,6 +91,11 @@ func (a *Append) Append(
 
 	allres = append(allres, outres)
 
+	// reorder slice
+	sort.Slice(allres, func(i, j int) bool {
+		return allres[i].Time.Before(allres[j].Time)
+	})
+
 	// encode output
 	enc := json.NewEncoder(out)
 	if err := enc.Encode(allres); err != nil {
diff --git a/wpt/wpt.go b/wpt/wpt.go
index 4b0464d..bda086b 100644
--- a/wpt/wpt.go
+++ b/wpt/wpt.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"sort"
 	"time"
 
 	"github.com/lightpanda-io/perf-fmt/git"
@@ -85,6 +86,11 @@ func (a *Append) Append(
 
 	allres = append(allres, outres)
 
+	// reorder slice
+	sort.Slice(allres, func(i, j int) bool {
+		return allres[i].Time.Before(allres[j].Time)
+	})
+
 	// encode output
 	enc := json.NewEncoder(out)
 	if err := enc.Encode(allres); err != nil {