diff --git a/src/jsonpak/private/bitabs.nim b/src/jsonpak/private/bitabs.nim
index adb9983..611d4cb 100644
--- a/src/jsonpak/private/bitabs.nim
+++ b/src/jsonpak/private/bitabs.nim
@@ -18,7 +18,7 @@ type
 
 proc slotsNeeded(count: Natural): int {.inline.} =
   # Make sure to synchronize with `mustRehash`
-  result = nextPowerOfTwo(count * 3 div 2 + 4)
+  result = nextPowerOfTwo(count div 2 + count + 4)
 
 proc initBiTable*[T](initialSize = defaultInitialSize): BiTable[T] =
   BiTable[T](vals: @[], keys: newSeq[Key](slotsNeeded(initialSize)))
@@ -39,7 +39,7 @@ proc len*[T](t: BiTable[T]): int = t.vals.len
 
 proc mustRehash(length, counter: int): bool {.inline.} =
   assert(length > counter)
-  result = (length * 2 < counter * 3) or (length - counter < 4)
+  result = (length < (counter + counter div 2)) or (length - counter < 4)
 
 const
   idStart = 1
diff --git a/tests/tparser.nim b/tests/tparser.nim
index 7eecdff..892da79 100644
--- a/tests/tparser.nim
+++ b/tests/tparser.nim
@@ -21,7 +21,7 @@ proc main =
     for data in items(invalid):
       try:
         discard parseJson(data)
-        assert false, "Expected PathError"
+        assert false, "Expected JsonParsingError"
       except JsonParsingError:
         assert true