diff --git a/comfy/utils.py b/comfy/utils.py
index 1bc35df7..78f8314f 100644
--- a/comfy/utils.py
+++ b/comfy/utils.py
@@ -713,7 +713,9 @@ def common_upscale(samples, width, height, upscale_method, crop):
             return torch.nn.functional.interpolate(s, size=(height, width), mode=upscale_method)
 
 def get_tiled_scale_steps(width, height, tile_x, tile_y, overlap):
-    return math.ceil((height / (tile_y - overlap))) * math.ceil((width / (tile_x - overlap)))
+    rows = 1 if height <= tile_y else math.ceil((height - overlap) / (tile_y - overlap))
+    cols = 1 if width <= tile_x else math.ceil((width - overlap) / (tile_x - overlap))
+    return rows * cols
 
 @torch.inference_mode()
 def tiled_scale_multidim(samples, function, tile=(64, 64), overlap = 8, upscale_amount = 4, out_channels = 3, output_device="cpu", pbar = None):
@@ -722,10 +724,20 @@ def tiled_scale_multidim(samples, function, tile=(64, 64), overlap = 8, upscale_
 
     for b in range(samples.shape[0]):
         s = samples[b:b+1]
+
+        # handle entire input fitting in a single tile
+        if all(s.shape[d+2] <= tile[d] for d in range(dims)):
+            output[b:b+1] = function(s).to(output_device)
+            if pbar is not None:
+                pbar.update(1)
+            continue
+
         out = torch.zeros([s.shape[0], out_channels] + list(map(lambda a: round(a * upscale_amount), s.shape[2:])), device=output_device)
         out_div = torch.zeros([s.shape[0], out_channels] + list(map(lambda a: round(a * upscale_amount), s.shape[2:])), device=output_device)
 
-        for it in itertools.product(*map(lambda a: range(0, a[0], a[1] - overlap), zip(s.shape[2:], tile))):
+        positions = [range(0, s.shape[d+2], tile[d] - overlap) if s.shape[d+2] > tile[d] else [0] for d in range(dims)]
+
+        for it in itertools.product(*positions):
             s_in = s
             upscaled = []
 
@@ -734,15 +746,16 @@ def tiled_scale_multidim(samples, function, tile=(64, 64), overlap = 8, upscale_
                 l = min(tile[d], s.shape[d + 2] - pos)
                 s_in = s_in.narrow(d + 2, pos, l)
                 upscaled.append(round(pos * upscale_amount))
+
             ps = function(s_in).to(output_device)
             mask = torch.ones_like(ps)
             feather = round(overlap * upscale_amount)
+
             for t in range(feather):
                 for d in range(2, dims + 2):
-                    m = mask.narrow(d, t, 1)
-                    m *= ((1.0/feather) * (t + 1))
-                    m = mask.narrow(d, mask.shape[d] -1 -t, 1)
-                    m *= ((1.0/feather) * (t + 1))
+                    a = (t + 1) / feather
+                    mask.narrow(d, t, 1).mul_(a)
+                    mask.narrow(d, mask.shape[d] - 1 - t, 1).mul_(a)
 
             o = out
             o_d = out_div
@@ -750,8 +763,8 @@ def tiled_scale_multidim(samples, function, tile=(64, 64), overlap = 8, upscale_
                 o = o.narrow(d + 2, upscaled[d], mask.shape[d + 2])
                 o_d = o_d.narrow(d + 2, upscaled[d], mask.shape[d + 2])
 
-            o += ps * mask
-            o_d += mask
+            o.add_(ps * mask)
+            o_d.add_(mask)
 
             if pbar is not None:
                 pbar.update(1)