diff --git a/README.md b/README.md
index 062d795..7d05bad 100644
--- a/README.md
+++ b/README.md
@@ -37,20 +37,27 @@ The first crawl asks for the Telegram login code once, then stores the session i
 
 ## Compare two crawls
 
-Compare membership changes for one group between two saved crawls:
+Compare membership changes for one group between two saved crawls with the
+git-diff-style terminal output:
 
 ```bash
 python compare.py <group_id> <time1> <time2>
 ```
 
-If `time1` and `time2` are omitted, the command compares the latest two crawls for that group:
+If `time1` and `time2` are omitted, the command compares the latest two crawls
+for that group:
 
 ```bash
 python compare.py <group_id>
 ```
 
-The output uses a git-diff-style view: removed members are prefixed with `-`,
-added members are prefixed with `+`, and the hunk header shows member counts.
+For a WinMerge-style side-by-side table, use:
+
+```bash
+python compareui.py <group_id> <time1> <time2>
+```
+
+It accepts the same optional `time1 time2` arguments as `compare.py`.
 
 ## Configuration
 
diff --git a/compareui.py b/compareui.py
new file mode 100644
index 0000000..464bfe6
--- /dev/null
+++ b/compareui.py
@@ -0,0 +1,143 @@
+import sys
+
+from compare import parse_args
+
+RESET = '\033[0m'
+YELLOW_BG = '\033[43m'
+BLACK = '\033[30m'
+DIVIDER = ' | '
+
+
+def main():
+    args = parse_args()
+
+    from common import diff_group_members, get_group_export, latest_two_group_exports
+
+    if args.times:
+        before_time, after_time = args.times
+        before_record = get_group_export(args.group_id, before_time)
+        after_record = get_group_export(args.group_id, after_time)
+        if before_record is None:
+            print(f'export not found for group {args.group_id} at {before_time}', file=sys.stderr)
+            return 1
+        if after_record is None:
+            print(f'export not found for group {args.group_id} at {after_time}', file=sys.stderr)
+            return 1
+    else:
+        before_record, after_record = latest_two_group_exports(args.group_id)
+        if before_record is None or after_record is None:
+            print(f'need at least 2 exports for group {args.group_id}', file=sys.stderr)
+            return 1
+
+    added, removed = diff_group_members(before_record, after_record)
+    print_compare_ui(args.group_id, before_record, after_record, added, removed)
+    return 0
+
+
+def print_compare_ui(group_id, before_record, after_record, added, removed):
+    title = after_record.get('title') or before_record.get('title') or ''
+    before_members = before_record.get('members', [])
+    after_members = after_record.get('members', [])
+    before_time = before_record.get('time')
+    after_time = after_record.get('time')
+    label = f'{title} ({group_id})' if title else str(group_id)
+
+    rows = side_by_side_rows(removed, added)
+    widths = table_widths(rows)
+    left_width = side_width(widths)
+    right_width = left_width
+
+    print(f'compare --telegram-group "{label}"')
+    print(
+        f'old: {before_time} ({len(before_members)} members)'.ljust(left_width)
+        + DIVIDER
+        + f'new: {after_time} ({len(after_members)} members)'.ljust(right_width)
+    )
+    print(
+        f'removed: {len(removed)}'.ljust(left_width)
+        + DIVIDER
+        + f'added: {len(added)}'.ljust(right_width)
+    )
+    print()
+    print(format_table_header(widths))
+    print(format_separator(widths))
+
+    for row in rows:
+        print(highlight(format_table_row(row, widths)))
+
+    if not added and not removed:
+        print('no membership changes.')
+
+
+def highlight(text):
+    if not sys.stdout.isatty():
+        return text
+    return f'{YELLOW_BG}{BLACK}{text}{RESET}'
+
+
+def side_by_side_rows(removed, added):
+    rows = []
+    max_count = max(len(removed), len(added))
+    for index in range(max_count):
+        left = member_columns(removed[index]) if index < len(removed) else empty_columns()
+        right = member_columns(added[index]) if index < len(added) else empty_columns()
+        rows.append((left, right))
+    return rows
+
+
+def member_columns(member):
+    username = member.get('username')
+    full_name = ' '.join(
+        part for part in [member.get('first_name'), member.get('last_name')]
+        if part
+    )
+    return [
+        str(member.get('id')),
+        f'@{username}' if username else '',
+        full_name,
+    ]
+
+
+def empty_columns():
+    return ['', '', '']
+
+
+def table_widths(rows):
+    widths = [2, 8, 4]
+    for left, right in rows:
+        for columns in (left, right):
+            for index, value in enumerate(columns):
+                widths[index] = max(widths[index], len(value))
+    return widths
+
+
+def side_width(widths):
+    return sum(widths) + 4
+
+
+def format_table_header(widths):
+    labels = ['ID', 'Username', 'Name']
+    left = format_columns(labels, widths)
+    right = format_columns(labels, widths)
+    return f'{left}{DIVIDER}{right}'
+
+
+def format_separator(widths):
+    return f'{"-" * side_width(widths)}-+-{"-" * side_width(widths)}'
+
+
+def format_table_row(row, widths):
+    left, right = row
+    return f'{format_columns(left, widths)}{DIVIDER}{format_columns(right, widths)}'
+
+
+def format_columns(columns, widths):
+    return (
+        f'{columns[0]:<{widths[0]}}  '
+        f'{columns[1]:<{widths[1]}}  '
+        f'{columns[2]:<{widths[2]}}'
+    )
+
+
+if __name__ == '__main__':
+    raise SystemExit(main())