diff --git a/train.py b/train.py
index f1c1581e..4bcdaf3c 100755
--- a/train.py
+++ b/train.py
@@ -761,7 +761,7 @@ def validate(model, loader, loss_fn, args, amp_autocast=suppress, log_suffix='')
                 target = target[0:target.size(0):reduce_factor]
 
             loss = loss_fn(output, target)
-            acc1, acc5 = accuracy(output, target, topk=(1, 5))
+            acc1, acc5 = accuracy(output, target, topk=(1, min(5, model.num_classes)))
 
             if args.distributed:
                 reduced_loss = reduce_tensor(loss.data, args.world_size)