diff --git a/pyscf/pbc/tools/pbc.py b/pyscf/pbc/tools/pbc.py
index 397a0d9a28..d67521e45b 100644
--- a/pyscf/pbc/tools/pbc.py
+++ b/pyscf/pbc/tools/pbc.py
@@ -465,9 +465,17 @@ def madelung(cell, kpts):
         return 2*cell.omega/np.pi**0.5-np.einsum('i,i,i->', ZSI.conj(), ZSI, coulG*weights).real
 
 
-def get_monkhorst_pack_size(cell, kpts):
-    skpts = cell.get_scaled_kpts(kpts).round(decimals=6)
-    Nk = np.array([len(np.unique(ki)) for ki in skpts.T])
+def get_monkhorst_pack_size(cell, kpts, tol=1e-5):
+    kpts = np.reshape(kpts, (-1,3))
+    min_tol = tol
+    assert kpts.shape[0] < 1/min_tol
+    if kpts.shape[0] == 1:
+        Nk = np.array([1,1,1])
+    else:
+        tol = max(10**(-int(-np.log10(1/kpts.shape[0]))-2), min_tol)
+        skpts = cell.get_scaled_kpts(kpts)
+        Nk = np.array([np.count_nonzero(abs(ski[1:]-ski[:-1]) > tol) + 1
+                       for ski in np.sort(skpts.T)])
     return Nk