diff --git a/db/migrate/20200912190210_update_weight_calculators.rb b/db/migrate/20200912190210_update_weight_calculators.rb
new file mode 100644
index 0000000000..4ee5a0dfc0
--- /dev/null
+++ b/db/migrate/20200912190210_update_weight_calculators.rb
@@ -0,0 +1,10 @@
+class UpdateWeightCalculators < ActiveRecord::Migration
+  def change
+    Calculator::Weight.each { |calculator|
+      calculator.preferred_unit_from_list = 'kg'
+      calculator.preferred_per_unit = calculator.preferred_per_kg
+      calculator.preferences.delete(:preferred_per_kg)
+      calculator.save
+    }
+  end
+end