diff --git a/api/api_v1/endpoints/query.py b/api/api_v1/endpoints/query.py
index a172374..c9bc587 100644
--- a/api/api_v1/endpoints/query.py
+++ b/api/api_v1/endpoints/query.py
@@ -168,9 +168,9 @@ async def event_model(
             df = pd.concat([df, pd.DataFrame(concat_data, columns=df.columns)])
             df.sort_values('date', inplace=True)
             if len(df) >= 2:
-                q['chain_ratio'] = round((df.iloc[-1, 1] - df.iloc[-2, 1]) * 100 / df.iloc[-2, 1], 2)
+                q['chain_ratio'] = division((df.iloc[-1, 1] - df.iloc[-2, 1]) * 100 , df.iloc[-2, 1], 2)
             if len(df) >= 8:
-                q['wow'] = round((df.iloc[-1, 1] - df.iloc[-8, 1]) * 100 / df.iloc[-8, 1], 2)
+                q['wow'] = division((df.iloc[-1, 1] - df.iloc[-8, 1]) * 100 / df.iloc[-8, 1], 2) or 0
             q['values'].append(df['values'].to_list())
             q['sum'].append(int(df['values'].sum()))
         if item['time_particle'] in ('P1D', 'P1W'):
diff --git a/common/compute.py b/common/compute.py
index 05a5aa6..38e7bd5 100644
--- a/common/compute.py
+++ b/common/compute.py
@@ -1,7 +1,10 @@
+import numpy as np
 def division(a, b, n=2):
     res = 0
     try:
         res = round(a / b, n)
+        if np.isnan(res):
+            res = 0
     except ZeroDivisionError:
         pass
     return res