diff --git a/comfy/ldm/cogvideo/vae.py b/comfy/ldm/cogvideo/vae.py
index fe97f362c..dd63522b1 100644
--- a/comfy/ldm/cogvideo/vae.py
+++ b/comfy/ldm/cogvideo/vae.py
@@ -453,13 +453,13 @@ class AutoencoderKLCogVideoX(nn.Module):
     def encode(self, x):
         t = x.shape[2]
         frame_batch = self.num_sample_frames_batch_size
-        num_batches = max(t // frame_batch, 1)
+        # ceil so remainder frames get their own chunk instead of inflating the first one
+        num_batches = max(-(-t // frame_batch), 1)
         conv_cache = None
         enc = []
         for i in range(num_batches):
-            remaining = t % frame_batch
-            start = frame_batch * i + (0 if i == 0 else remaining)
-            end = frame_batch * (i + 1) + remaining
+            start = i * frame_batch
+            end = min((i + 1) * frame_batch, t)
             chunk, conv_cache = self.encoder(x[:, :, start:end], conv_cache=conv_cache)
             enc.append(chunk.to(x.device))
         enc = torch.cat(enc, dim=2)