diff --git a/geomagio/residual/Calculation.py b/geomagio/residual/Calculation.py
index 55a40d314c1ac7a795564e55a77aceaf4401ea47..84b3051f02712b15afd95e0e48ff8d73af651e9c 100644
--- a/geomagio/residual/Calculation.py
+++ b/geomagio/residual/Calculation.py
@@ -59,7 +59,7 @@ def calculate(reading: Reading, adjust_reference: bool = True) -> Reading:
         h_baseline=absoluteH.baseline,
         measurements=reading.measurements,
         reference=reference,
-        shift=reading.absolutes[0].shift,
+        shift=reading.absolutes[0].shift if reading.absolutes else 0,
     )
 
     d_computed = calculate_D_computed(