diff --git a/artiq/dashboard/datasets.py b/artiq/dashboard/datasets.py
index 97146bb33..f7c996849 100644
--- a/artiq/dashboard/datasets.py
+++ b/artiq/dashboard/datasets.py
@@ -81,8 +81,7 @@ class CreateEditDialog(QtWidgets.QDialog):
             t = value.dtype if value is np.ndarray else type(value)
             if scale != 1 and np.issubdtype(t, np.number):
                 # degenerates to float type
-                value_edit_string = self.value_to_edit_string(
-                        np.float64(value / scale))
+                value_edit_string = self.value_to_edit_string(value / scale)
             self.unit_widget.setText(metadata.get('unit', ''))
             self.scale_widget.setText(str(metadata.get('scale', '')))
             self.precision_widget.setText(str(metadata.get('precision', '')))
@@ -109,7 +108,7 @@ class CreateEditDialog(QtWidgets.QDialog):
         t = value.dtype if value is np.ndarray else type(value)
         if scale != 1 and np.issubdtype(t, np.number):
             # degenerates to float type
-            value = np.float64(value * scale)
+            value = float(value * scale)
         if self.key and self.key != key:
             asyncio.ensure_future(exc_to_warning(rename(self.key, key, value, metadata, persist, self.dataset_ctl)))
         else: