diff --git a/fs/accounting/stats.go b/fs/accounting/stats.go
index b029cb590..f808e1fdf 100644
--- a/fs/accounting/stats.go
+++ b/fs/accounting/stats.go
@@ -229,6 +229,11 @@ func (s *StatsInfo) totalDuration() time.Duration {
 	return s.oldDuration + timeRanges.total()
 }
 
+const (
+	etaMaxSeconds = (1<<63 - 1) / int64(time.Second)           // Largest possible ETA as number of seconds
+	etaMax        = time.Duration(etaMaxSeconds) * time.Second // Largest possible ETA, which is in second precision, representing "292y24w3d23h47m16s"
+)
+
 // eta returns the ETA of the current operation,
 // rounded to full seconds.
 // If the ETA cannot be determined 'ok' returns false.
@@ -240,11 +245,17 @@ func eta(size, total int64, rate float64) (eta time.Duration, ok bool) {
 	if remaining < 0 {
 		return 0, false
 	}
-	seconds := float64(remaining) / rate
+	seconds := int64(float64(remaining) / rate)
 	if seconds < 0 {
-		seconds = 0
+		// Got Int64 overflow
+		eta = etaMax
+	} else if seconds >= etaMaxSeconds {
+		// Would get Int64 overflow if converting from seconds to Duration (nanoseconds)
+		eta = etaMax
+	} else {
+		eta = time.Duration(seconds) * time.Second
 	}
-	return time.Second * time.Duration(seconds), true
+	return eta, true
 }
 
 // etaString returns the ETA of the current operation,
@@ -255,6 +266,9 @@ func etaString(done, total int64, rate float64) string {
 	if !ok {
 		return "-"
 	}
+	if d == etaMax {
+		return "-"
+	}
 	return fs.Duration(d).ReadableString()
 }
 
diff --git a/fs/accounting/stats_test.go b/fs/accounting/stats_test.go
index c22f0031b..b1a3cbb2a 100644
--- a/fs/accounting/stats_test.go
+++ b/fs/accounting/stats_test.go
@@ -31,6 +31,9 @@ func TestETA(t *testing.T) {
 		{size: 0, total: 1.5 * 86400, rate: 1.0, wantETA: 1.5 * 86400 * time.Second, wantOK: true, wantString: "1d12h"},
 		{size: 0, total: 95000, rate: 1.0, wantETA: 95000 * time.Second, wantOK: true, wantString: "1d2h23m20s"},
 		// Standard Duration String Cases
+		{size: 0, total: 1, rate: 2.0, wantETA: 0, wantOK: true, wantString: "0s"},
+		{size: 0, total: 1, rate: 1.0, wantETA: time.Second, wantOK: true, wantString: "1s"},
+		{size: 0, total: 1, rate: 0.5, wantETA: 2 * time.Second, wantOK: true, wantString: "2s"},
 		{size: 0, total: 100, rate: 1.0, wantETA: 100 * time.Second, wantOK: true, wantString: "1m40s"},
 		{size: 50, total: 100, rate: 1.0, wantETA: 50 * time.Second, wantOK: true, wantString: "50s"},
 		{size: 100, total: 100, rate: 1.0, wantETA: 0 * time.Second, wantOK: true, wantString: "0s"},
@@ -41,10 +44,15 @@ func TestETA(t *testing.T) {
 		{size: 10, total: 20, rate: 0.0, wantETA: 0, wantOK: false, wantString: "-"},
 		{size: 10, total: 20, rate: -1.0, wantETA: 0, wantOK: false, wantString: "-"},
 		{size: 0, total: 0, rate: 1.0, wantETA: 0, wantOK: false, wantString: "-"},
+		// Extreme Cases
+		{size: 0, total: (1 << 63) - 1, rate: 1.0, wantETA: (time.Duration((1<<63)-1) / time.Second) * time.Second, wantOK: true, wantString: "-"},
+		{size: 0, total: ((1 << 63) - 1) / int64(time.Second), rate: 1.0, wantETA: (time.Duration((1<<63)-1) / time.Second) * time.Second, wantOK: true, wantString: "-"},
+		{size: 0, total: ((1<<63)-1)/int64(time.Second) - 1, rate: 1.0, wantETA: (time.Duration((1<<63)-1)/time.Second - 1) * time.Second, wantOK: true, wantString: "292y24w3d23h47m15s"},
+		{size: 0, total: ((1<<63)-1)/int64(time.Second) - 1, rate: 0.1, wantETA: (time.Duration((1<<63)-1) / time.Second) * time.Second, wantOK: true, wantString: "-"},
 	} {
 		t.Run(fmt.Sprintf("size=%d/total=%d/rate=%f", test.size, test.total, test.rate), func(t *testing.T) {
 			gotETA, gotOK := eta(test.size, test.total, test.rate)
-			assert.Equal(t, test.wantETA, gotETA)
+			assert.Equal(t, int64(test.wantETA), int64(gotETA))
 			assert.Equal(t, test.wantOK, gotOK)
 			gotString := etaString(test.size, test.total, test.rate)
 			assert.Equal(t, test.wantString, gotString)