diff --git a/src/image_prediction/encoder/encoders/hash_encoder.py b/src/image_prediction/encoder/encoders/hash_encoder.py
index c21bacd..0266a84 100644
--- a/src/image_prediction/encoder/encoders/hash_encoder.py
+++ b/src/image_prediction/encoder/encoders/hash_encoder.py
@@ -13,7 +13,7 @@ class HashEncoder(Encoder):
         yield from self.encode(images)
 
 
-def hash_image(image: Image.Image):
+def hash_image(image: Image.Image) -> str:
     """See: https://stackoverflow.com/a/49692185/3578468"""
     image = image.resize((10, 10), Image.ANTIALIAS)
     image = image.convert("L")
@@ -21,4 +21,6 @@ def hash_image(image: Image.Image):
     avg_pixel = sum(pixel_data) / len(pixel_data)
     bits = "".join(["1" if (px >= avg_pixel) else "0" for px in pixel_data])
     hex_representation = str(hex(int(bits, 2)))[2:][::-1].upper()
-    return hex_representation
+    # Note: For each 4 leading zeros, the hex representation will be shorter by one character.
+    # To ensure that all hashes have the same length, we pad the hex representation with zeros (also see RED-3813).
+    return hex_representation.zfill(25)
diff --git a/test/data.dvc b/test/data.dvc
index c7040fe..b7fe73d 100644
--- a/test/data.dvc
+++ b/test/data.dvc
@@ -1,5 +1,5 @@
 outs:
-- md5: 4b0fec291ce0661b3efbbd8b80f4f514.dir
-  size: 107332
-  nfiles: 4
+- md5: 11f42db1ef57bcac9547792c5506583c.dir
+  size: 1118031
+  nfiles: 5
   path: data
diff --git a/test/unit_tests/encoder_test.py b/test/unit_tests/encoder_test.py
index 5102aca..5524197 100644
--- a/test/unit_tests/encoder_test.py
+++ b/test/unit_tests/encoder_test.py
@@ -1,12 +1,15 @@
 import random
 from itertools import starmap
 from operator import __eq__
+from pathlib import Path
 
 import pytest
 from PIL.Image import Image
 from funcy import compose, first
 
-from image_prediction.encoder.encoders.hash_encoder import HashEncoder, hash_image
+from image_prediction.encoder.encoders.hash_encoder import HashEncoder
+from image_prediction.encoder.encoders.hash_encoder import hash_image
+from image_prediction.image_extractor.extractors.parsable import ParsablePDFImageExtractor
 from image_prediction.utils.generic import lift
 
 
@@ -29,3 +32,17 @@ def test_hash_encoder(images, hashed_images, base_patch_image):
     hashed_resized = compose(first, encoder, lift(resize))([base_patch_image])
     hashed = hash_image(base_patch_image)
     assert close(hashed_resized, hashed)
+
+
+def test_all_hashes_have_length_of_twentyfive():
+    """See RED-3814: all hashes should have 25 characters."""
+    pdf_path = Path(__file__).parents[1] / "data" / "similarImages2.pdf"
+    pdf_bytes = pdf_path.read_bytes()
+    image_extractor = ParsablePDFImageExtractor()
+    image_metadata_pairs = list(image_extractor.extract(pdf_bytes))
+    images = [image for image, _ in image_metadata_pairs]
+
+    hash_encoder = HashEncoder()
+    hashes = list(hash_encoder.encode(images))
+
+    assert all(len(h) == 25 for h in hashes)