diff --git a/setup.py b/setup.py
index c587255f..348be5fa 100644
--- a/setup.py
+++ b/setup.py
@@ -30,7 +30,7 @@
 
 setup(
         name="pyqcs"
-        , version="2.6.1"
+        , version="2.6.2"
         , description="A quantum computing simulator."
         , long_description = open("README.rst").read()
         , ext_modules=[basic_gates
diff --git a/src/pyqcs/measurement.py b/src/pyqcs/measurement.py
index 1f75ba0e..13534b6c 100644
--- a/src/pyqcs/measurement.py
+++ b/src/pyqcs/measurement.py
@@ -139,8 +139,8 @@ def compute_amplitude(state, qbits, bitstr):
 
     check_bits = sum(1 << qbit for qbit in qbits)
     bit_mask = sum(1 << bit for bit,msk in zip(qbits, bitstr) if msk)
-    if(max(qbits) > state._nqbits):
-        raise ValueError(f"qbit {max(qbits)} out of range: {state._nqbits}")
+    if(max(qbits) > state._nbits):
+        raise ValueError(f"qbit {max(qbits)} out of range: {state._nbits}")
 
     amplitude = 0
     for i,v in enumerate(state._qm_state):
@@ -167,8 +167,8 @@ def compute_amplitudes(state, qbits, eps=1e-8, asint=True):
         qbits = [i for i in range(qbits.bit_length()) if qbits & (1 << i)]
     if(not isinstance(qbits, (list, tuple))):
         raise TypeError("qbits must be int, list, or tuple")
-    if(max(qbits) > state._nqbits):
-        raise ValueError(f"qbit {max(qbits)} out of range: {state._nqbits}")
+    if(max(qbits) > state._nbits):
+        raise ValueError(f"qbit {max(qbits)} out of range: {state._nbits}")
 
     single_qbit_outcomes = [0, 1]