diff --git a/app/models/ingredient.rb b/app/models/ingredient.rb
index ac0dcbc..661fa93 100644
--- a/app/models/ingredient.rb
+++ b/app/models/ingredient.rb
@@ -49,25 +49,7 @@ class Ingredient < ActiveRecord::Base
     self.kcal = food.kcal
     self.fiber = food.fiber
     self.sugar = food.sugar
-    self.density = calculate_density(food.gram_weight_1, food.gram_weight_desc_1) || calculate_density(food.gram_weight_2, food.gram_weight_desc_2)
-  end
-
-  def calculate_density(grams, description)
-    return nil if grams.blank? || description.blank?
-
-    begin
-      value_unit = UnitConversion.parse(description)
-      if value_unit.volume?
-        density_value = grams.to_d / value_unit.raw_value
-        density_units = "g/#{value_unit.unit.unit}"
-        density = UnitConversion.parse(density_value, density_units)
-        return density.convert('oz/cup').to_s
-      else
-        return nil
-      end
-    rescue UnitConversion::UnparseableUnitError
-      return nil
-    end
+    self.density = food.density_best_guess
   end
 
 end
diff --git a/app/models/usda_food.rb b/app/models/usda_food.rb
index 824406e..41b32d1 100644
--- a/app/models/usda_food.rb
+++ b/app/models/usda_food.rb
@@ -14,9 +14,8 @@ class UsdaFood < ActiveRecord::Base
   end
 
   def density_best_guess
-    usda_food_weights.each do |w|
-
-    end
+    density = usda_food_weights.map { |w| w.calculate_density }.compact.first
+    density.nil? ? nil : density.to_s
   end
 
 end
\ No newline at end of file
diff --git a/app/models/usda_food_weight.rb b/app/models/usda_food_weight.rb
index fdd05d0..8ef4b0a 100644
--- a/app/models/usda_food_weight.rb
+++ b/app/models/usda_food_weight.rb
@@ -20,4 +20,4 @@ class UsdaFoodWeight < ActiveRecord::Base
     end
   end
 
-end
\ No newline at end of file
+end
diff --git a/lib/unit_conversion/constants.rb b/lib/unit_conversion/constants.rb
index ea15492..7202bfd 100644
--- a/lib/unit_conversion/constants.rb
+++ b/lib/unit_conversion/constants.rb
@@ -15,11 +15,12 @@ module UnitConversion
       '[qt_us]': %w(quart quarts qt),
       '[gal_us]': %w(gallon gallons ga),
       '[foz_us]': %w(foz floz),
+      '[in_i]': %w(inch inches in)
   }
 
   METRIC_UNIT_ALIASES = {
       g: %w(gram grams),
-      kg: %w(kilograms kilogram),
+      kg: %w(kilogram kilograms),
 
       ml: %w(milliliter milliliters),
       cl: %w(centiliter centiliters),
diff --git a/lib/unit_conversion/parsed_unit.rb b/lib/unit_conversion/parsed_unit.rb
index 0dd000f..64c9028 100644
--- a/lib/unit_conversion/parsed_unit.rb
+++ b/lib/unit_conversion/parsed_unit.rb
@@ -56,6 +56,9 @@ module UnitConversion
       # fluid ounce is the only known unit with a space; fix it up before the following replacement
       unit_description = unit_description.gsub(/fl oz/i, 'floz')
 
+      # if a cubic unit is found, map it to unit3 (ex 'cubic inches' is converted to 'inches3')
+      unit_description = unit_description.gsub(/cubic\s+(\w+)/i, '\13')
+
       unit_description.downcase.gsub(/[a-z_\[\]]+/) do |match|
         UNIT_ALIAS_MAP[match] || match
       end
diff --git a/spec/lib/unit_conversion/parsed_unit_spec.rb b/spec/lib/unit_conversion/parsed_unit_spec.rb
index 2af76b0..fd0a3fb 100644
--- a/spec/lib/unit_conversion/parsed_unit_spec.rb
+++ b/spec/lib/unit_conversion/parsed_unit_spec.rb
@@ -12,7 +12,10 @@ RSpec.describe UnitConversion::ParsedUnit do
         'Grams' => 'g',
         'Tbsp' => '[tbs_us]',
         '[tbs_us]' => '[tbs_us]',
-        '[oz_av]' => '[oz_av]'
+        '[oz_av]' => '[oz_av]',
+        'cubic inch' => '[in_i]3',
+        'in3' => '[in_i]3'
+
     }
 
     data.each do |input, output|
diff --git a/spec/lib/unit_conversion/value_unit_spec.rb b/spec/lib/unit_conversion/value_unit_spec.rb
index 046c264..6189f8a 100644
--- a/spec/lib/unit_conversion/value_unit_spec.rb
+++ b/spec/lib/unit_conversion/value_unit_spec.rb
@@ -44,6 +44,14 @@ RSpec.describe UnitConversion::ValueUnit do
     it 'Converts parsed objects' do
       check_vu(UnitConversion::ValueUnit.for(UnitConversion::ParsedNumber.new('5'), UnitConversion::ParsedUnit.new('cups')), 5, 'cup')
     end
+
+    it 'converts multi word units' do
+      check_vu(UnitConversion::ValueUnit.for('2 cubic inches'), 2, 'inch3')
+    end
+
+    it 'understands cubic inches to be volume' do
+      expect(UnitConversion::ValueUnit.for('2 cubic inches').volume?).to be_truthy
+    end
   end
 
 end
\ No newline at end of file