diff --git a/netam/common.py b/netam/common.py
index 0250aa83..c50200a3 100644
--- a/netam/common.py
+++ b/netam/common.py
@@ -3,6 +3,9 @@
 import itertools
 import resource
 import subprocess
+from tqdm import tqdm
+from functools import wraps
+from itertools import islice
 
 import numpy as np
 import torch
@@ -380,3 +383,58 @@ def encode_sequences(sequences, encoder):
         torch.stack(masks),
         torch.stack(wt_base_modifiers),
     )
+
+
+# from https://docs.python.org/3.11/library/itertools.html#itertools-recipes
+# avoiding walrus:
+def chunked(iterable, n):
+    "Chunk data into lists of length n. The last chunk may be shorter."
+    it = iter(iterable)
+    while True:
+        chunk = list(islice(it, n))
+        if not chunk:
+            return
+        yield chunk
+
+
+def chunk_method(default_chunk_size=2048, progress_bar_name=None):
+    """Decorator to chunk the input to a method.
+
+    Expects that all positional arguments are iterables of the same length,
+    and that outputs are tuples of tensors whose first dimension
+    corresponds to the first dimension of the input iterables.
+
+    If method returns just one item, it must not be a tuple.
+
+    Chunking is done along the first dimension of all inputs.
+
+    Args:
+        default_chunk_size: The default chunk size. The decorated method can
+            also automatically accept a `default_chunk_size` keyword argument.
+        progress_bar_name: The name of the progress bar. If None, no progress bar is shown.
+    """
+
+    def decorator(method):
+        @wraps(method)
+        def wrapper(self, *args, **kwargs):
+            if "chunk_size" in kwargs:
+                chunk_size = kwargs.pop("chunk_size")
+            else:
+                chunk_size = default_chunk_size
+            results = []
+            if progress_bar_name is None:
+                progargs = {"disable": True}
+            else:
+                progargs = {"desc": progress_bar_name}
+            bar = tqdm(total=len(args[0]), delay=2.0, **progargs)
+            for chunked_args in zip(*(chunked(arg, chunk_size) for arg in args)):
+                bar.update(len(chunked_args[0]))
+                results.append(method(self, *chunked_args, **kwargs))
+            if isinstance(results[0], tuple):
+                return tuple(torch.cat(tensors) for tensors in zip(*results))
+            else:
+                return torch.cat(results)
+
+        return wrapper
+
+    return decorator
diff --git a/netam/framework.py b/netam/framework.py
index be7cf500..ad4748e2 100644
--- a/netam/framework.py
+++ b/netam/framework.py
@@ -143,7 +143,9 @@ def export_branch_lengths(self, out_csv_path):
         )
 
     def load_branch_lengths(self, in_csv_path):
-        self.branch_lengths = pd.read_csv(in_csv_path)["branch_length"].values
+        self.branch_lengths = torch.Tensor(
+            pd.read_csv(in_csv_path)["branch_length"].values
+        )
 
     def __repr__(self):
         return f"{self.__class__.__name__}(Size: {len(self)}) on {self.branch_lengths.device}"
@@ -252,6 +254,11 @@ def __init__(self, encoder, model, training_hyperparameters={}):
         self.training_hyperparameters = training_hyperparameters
 
     def __call__(self, sequences):
+        """Evaluate the model on a list of sequences."""
+        if isinstance(sequences, str):
+            raise ValueError(
+                "Expected a list of sequences for call on crepe, but got a single string instead."
+            )
         return self.model.evaluate_sequences(sequences, encoder=self.encoder)
 
     @property
diff --git a/netam/models.py b/netam/models.py
index e5b13673..93293b8e 100644
--- a/netam/models.py
+++ b/netam/models.py
@@ -17,6 +17,7 @@
     generate_kmers,
     aa_mask_tensor_of,
     encode_sequences,
+    chunk_method,
 )
 
 warnings.filterwarnings(
@@ -64,7 +65,8 @@ def unfreeze(self):
         for param in self.parameters():
             param.requires_grad = True
 
-    def evaluate_sequences(self, sequences, encoder=None):
+    @chunk_method(progress_bar_name="Evaluating model")
+    def evaluate_sequences(self, sequences, encoder=None, chunk_size=2048):
         if encoder is None:
             raise ValueError("An encoder must be provided.")
         encoded_parents, masks, wt_base_modifiers = encode_sequences(sequences, encoder)