diff --git a/server/backend/internal/scheduler/scheduler.go b/server/backend/internal/scheduler/scheduler.go
index ab052f3..dcf6efe 100644
--- a/server/backend/internal/scheduler/scheduler.go
+++ b/server/backend/internal/scheduler/scheduler.go
@@ -113,6 +113,35 @@ func desiredState(onTime, offTime, now string) string {
 	return "off"
 }
 
+// resolveDesiredState ermittelt den Soll-Zustand eines Screens unter Berücksichtigung
+// aller Prioritätsstufen:
+//  1. per-Screen override_on_until (höchste Priorität)
+//  2. globaler Override
+//  3. Wochenende (Sa/So)
+//  4. normaler Zeitplan
+//
+// Gibt ("", false) zurück wenn keine Automatisierung aktiv ist.
+func resolveDesiredState(sc store.ScreenSchedule, globalOverride *store.GlobalOverride, now time.Time) (desired string, shouldControl bool) {
+	// 1. Per-Screen-Override: überschreibt alles
+	if sc.OverrideOnUntil != nil && now.Before(*sc.OverrideOnUntil) {
+		return "on", true
+	}
+	// 2. Globaler Override
+	if globalOverride != nil && now.Before(globalOverride.Until) {
+		return globalOverride.Type, true
+	}
+	// 3. Wochenende: Zeitpläne werden ignoriert, Monitore bleiben aus
+	wd := now.Weekday()
+	if wd == time.Saturday || wd == time.Sunday {
+		return "off", true
+	}
+	// 4. Normaler Zeitplan
+	if !sc.ScheduleEnabled || (sc.PowerOnTime == "" && sc.PowerOffTime == "") {
+		return "", false
+	}
+	return desiredState(sc.PowerOnTime, sc.PowerOffTime, now.Format("15:04")), true
+}
+
 // check prüft alle aktiven Zeitpläne und sendet ggf. Befehle.
 func check(ctx context.Context, schedules *store.ScreenScheduleStore, screens ScreenSlugGetter, notifier DisplayCommander) {
 	// Uses process-local timezone — ensure TZ env var is set in the container (e.g. Europe/Berlin).
diff --git a/server/backend/internal/scheduler/scheduler_test.go b/server/backend/internal/scheduler/scheduler_test.go
new file mode 100644
index 0000000..ffb6066
--- /dev/null
+++ b/server/backend/internal/scheduler/scheduler_test.go
@@ -0,0 +1,129 @@
+package scheduler
+
+import (
+	"testing"
+	"time"
+
+	"git.az-it.net/az/morz-infoboard/server/backend/internal/store"
+)
+
+func ptrTime(t time.Time) *time.Time { return &t }
+
+func TestResolveDesiredState(t *testing.T) {
+	// Donnerstag 10:00 UTC
+	thu := time.Date(2026, 3, 26, 10, 0, 0, 0, time.UTC)
+	// Samstag 10:00 UTC
+	sat := time.Date(2026, 3, 28, 10, 0, 0, 0, time.UTC)
+
+	tests := []struct {
+		name        string
+		sc          store.ScreenSchedule
+		override    *store.GlobalOverride
+		now         time.Time
+		wantDesired string
+		wantControl bool
+	}{
+		{
+			name:        "per-screen override aktiv → on",
+			sc:          store.ScreenSchedule{OverrideOnUntil: ptrTime(thu.Add(time.Hour))},
+			now:         thu,
+			wantDesired: "on", wantControl: true,
+		},
+		{
+			name: "per-screen override abgelaufen → fällt durch zu Zeitplan",
+			sc: store.ScreenSchedule{
+				ScheduleEnabled: true,
+				PowerOnTime:     "09:00", PowerOffTime: "17:00",
+				OverrideOnUntil: ptrTime(thu.Add(-time.Hour)), // abgelaufen
+			},
+			now:         thu,
+			wantDesired: "on", wantControl: true, // Zeitplan: 09:00–17:00, jetzt 10:00
+		},
+		{
+			name: "per-screen override schlägt globalen Override off",
+			sc:   store.ScreenSchedule{OverrideOnUntil: ptrTime(thu.Add(time.Hour))},
+			override: &store.GlobalOverride{
+				Type:  "off",
+				Until: thu.Add(time.Hour),
+			},
+			now:         thu,
+			wantDesired: "on", wantControl: true,
+		},
+		{
+			name: "globaler Override off aktiv → off",
+			sc:   store.ScreenSchedule{ScheduleEnabled: true, PowerOnTime: "09:00", PowerOffTime: "17:00"},
+			override: &store.GlobalOverride{
+				Type:  "off",
+				Until: thu.Add(time.Hour),
+			},
+			now:         thu,
+			wantDesired: "off", wantControl: true,
+		},
+		{
+			name: "globaler Override on aktiv → on",
+			sc:   store.ScreenSchedule{},
+			override: &store.GlobalOverride{
+				Type:  "on",
+				Until: thu.Add(time.Hour),
+			},
+			now:         thu,
+			wantDesired: "on", wantControl: true,
+		},
+		{
+			name: "globaler Override abgelaufen → fällt durch",
+			sc:   store.ScreenSchedule{ScheduleEnabled: true, PowerOnTime: "09:00", PowerOffTime: "17:00"},
+			override: &store.GlobalOverride{
+				Type:  "off",
+				Until: thu.Add(-time.Hour), // abgelaufen
+			},
+			now:         thu,
+			wantDesired: "on", wantControl: true,
+		},
+		{
+			name:        "Wochenende → off",
+			sc:          store.ScreenSchedule{ScheduleEnabled: true, PowerOnTime: "09:00", PowerOffTime: "17:00"},
+			now:         sat,
+			wantDesired: "off", wantControl: true,
+		},
+		{
+			name:        "Wochenende + per-screen override → on",
+			sc:          store.ScreenSchedule{OverrideOnUntil: ptrTime(sat.Add(time.Hour))},
+			now:         sat,
+			wantDesired: "on", wantControl: true,
+		},
+		{
+			name:        "normaler Zeitplan: innerhalb → on",
+			sc:          store.ScreenSchedule{ScheduleEnabled: true, PowerOnTime: "09:00", PowerOffTime: "17:00"},
+			now:         thu, // 10:00
+			wantDesired: "on", wantControl: true,
+		},
+		{
+			name:        "normaler Zeitplan: außerhalb → off",
+			sc:          store.ScreenSchedule{ScheduleEnabled: true, PowerOnTime: "09:00", PowerOffTime: "17:00"},
+			now:         time.Date(2026, 3, 26, 8, 0, 0, 0, time.UTC), // 08:00
+			wantDesired: "off", wantControl: true,
+		},
+		{
+			name:        "kein Zeitplan, kein Override → keine Steuerung",
+			sc:          store.ScreenSchedule{},
+			now:         thu,
+			wantDesired: "", wantControl: false,
+		},
+		{
+			name:        "Zeitplan deaktiviert → keine Steuerung",
+			sc:          store.ScreenSchedule{ScheduleEnabled: false, PowerOnTime: "09:00", PowerOffTime: "17:00"},
+			now:         thu,
+			wantDesired: "", wantControl: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotDesired, gotControl := resolveDesiredState(tt.sc, tt.override, tt.now)
+			if gotDesired != tt.wantDesired || gotControl != tt.wantControl {
+				t.Errorf("resolveDesiredState() = (%q, %v), want (%q, %v)",
+					gotDesired, gotControl, tt.wantDesired, tt.wantControl)
+			}
+		})
+	}
+}