--- a/testing/mochitest/runtestsremote.py
+++ b/testing/mochitest/runtestsremote.py
@@ -796,18 +796,17 @@ def main(args):
         mp.read(options.robocopIni)
         robocop_tests = mp.active_tests(exists=False, **mozinfo.info)
         tests = []
         my_tests = tests
         for test in robocop_tests:
             tests.append(test['name'])
 
         if options.totalChunks:
-            tests_per_chunk = math.ceil(
-                len(tests) / (options.totalChunks * 1.0))
+            tests_per_chunk = float(len(tests)) / options.totalChunks
             start = int(round((options.thisChunk - 1) * tests_per_chunk))
             end = int(round(options.thisChunk * tests_per_chunk))
             if end > len(tests):
                 end = len(tests)
             my_tests = tests[start:end]
             log.info("Running tests %d-%d/%d" % (start + 1, end, len(tests)))
 
         options.extraPrefs.append('browser.search.suggest.enabled=true')