diff --git a/internal/executor/sandbox/executor.go b/internal/executor/sandbox/executor.go
index 3c94326..c037bec 100644
--- a/internal/executor/sandbox/executor.go
+++ b/internal/executor/sandbox/executor.go
@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"log/slog"
 	"maps"
+	"math"
+	"time"
 
 	"github.com/criyle/go-judge/pb"
 	"github.com/joint-online-judge/JOJ3/internal/stage"
@@ -43,7 +45,7 @@ func (e *Sandbox) Run(ctx context.Context, cmds []stage.Cmd) ([]stage.ExecutorRe
 	pbReq := &pb.Request{}
 	pbReq.SetCmd(pbCmds)
 	slog.Debug("sandbox execute", "pbReq size", proto.Size(pbReq))
-	callCtx, cancel := context.WithTimeout(ctx, e.timeout)
+	callCtx, cancel := context.WithTimeout(ctx, execRPCTimeout(cmds))
 	defer cancel()
 	pbRet, err := e.execClient.Exec(callCtx, pbReq)
 	if err != nil {
@@ -64,7 +66,7 @@ func (e *Sandbox) Cleanup(ctx context.Context) error {
 	for k, fileID := range e.cachedMap {
 		req := &pb.FileID{}
 		req.SetFileID(fileID)
-		callCtx, cancel := context.WithTimeout(ctx, e.timeout)
+		callCtx, cancel := context.WithTimeout(ctx, rpcTimeoutMargin)
 		_, err := e.execClient.FileDelete(callCtx, req)
 		cancel()
 		if err != nil {
@@ -80,3 +82,29 @@ func (e *Sandbox) Cleanup(ctx context.Context) error {
 	}
 	return cleanupErr
 }
+
+func execRPCTimeout(cmds []stage.Cmd) time.Duration {
+	var maxLimit uint64
+	for _, cmd := range cmds {
+		limit := cmd.ClockLimit
+		if limit == 0 {
+			// Match the local executor's default wall-clock allowance when only a
+			// CPU limit is specified.
+			if cmd.CPULimit > math.MaxUint64/2 {
+				limit = math.MaxUint64
+			} else {
+				limit = cmd.CPULimit * 2
+			}
+		}
+		if limit > maxLimit {
+			maxLimit = limit
+		}
+	}
+
+	margin := uint64(rpcTimeoutMargin)
+	if maxLimit > uint64(math.MaxInt64)-margin {
+		return time.Duration(math.MaxInt64)
+	}
+	// The bound above guarantees the conversion fits in time.Duration.
+	return time.Duration(maxLimit + margin) // #nosec G115
+}
diff --git a/internal/executor/sandbox/executor_test.go b/internal/executor/sandbox/executor_test.go
new file mode 100644
index 0000000..0a164aa
--- /dev/null
+++ b/internal/executor/sandbox/executor_test.go
@@ -0,0 +1,42 @@
+package sandbox
+
+import (
+	"math"
+	"testing"
+	"time"
+
+	"github.com/joint-online-judge/JOJ3/internal/stage"
+)
+
+func TestExecRPCTimeout(t *testing.T) {
+	tests := []struct {
+		name string
+		cmds []stage.Cmd
+		want time.Duration
+	}{
+		{name: "margin only", want: rpcTimeoutMargin},
+		{
+			name: "largest clock limit",
+			cmds: []stage.Cmd{{ClockLimit: uint64(time.Minute)}, {ClockLimit: uint64(2 * time.Minute)}},
+			want: 2*time.Minute + rpcTimeoutMargin,
+		},
+		{
+			name: "cpu limit fallback",
+			cmds: []stage.Cmd{{CPULimit: uint64(time.Minute)}},
+			want: 2*time.Minute + rpcTimeoutMargin,
+		},
+		{
+			name: "duration overflow",
+			cmds: []stage.Cmd{{ClockLimit: math.MaxUint64}},
+			want: time.Duration(math.MaxInt64),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := execRPCTimeout(tt.cmds); got != tt.want {
+				t.Fatalf("execRPCTimeout() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
diff --git a/internal/executor/sandbox/meta.go b/internal/executor/sandbox/meta.go
index f327eec..0fe91c8 100644
--- a/internal/executor/sandbox/meta.go
+++ b/internal/executor/sandbox/meta.go
@@ -19,15 +19,15 @@ type Sandbox struct {
 	cachedMap         map[string]string
 	execClient        pb.ExecutorClient
 	conn              *grpc.ClientConn
-	timeout           time.Duration
 }
 
+const rpcTimeoutMargin = 30 * time.Second
+
 func init() {
 	stage.RegisterExecutor(name, &Sandbox{
 		execServer: "localhost:5051",
 		token:      "",
 		cachedMap:  make(map[string]string),
-		timeout:    30 * time.Second,
 	})
 }
 
@@ -37,6 +37,5 @@ func InitWithConf(execServer, token string) {
 		execServer: execServer,
 		token:      token,
 		cachedMap:  make(map[string]string),
-		timeout:    30 * time.Second,
 	})
 }