diff --git a/app/Http/Controllers/JournalEntryController.php b/app/Http/Controllers/JournalEntryController.php
index 43df249..44b70d2 100644
--- a/app/Http/Controllers/JournalEntryController.php
+++ b/app/Http/Controllers/JournalEntryController.php
@@ -82,7 +82,7 @@ class JournalEntryController extends Controller
                 ) {
                     continue;
                 }
-                $ingredients[] = [
+                $ingredients[$key] = [
                     'date' => $old['date'][$key],
                     'meal' => $old['meal'][$key],
                     'amount' => $amount,
@@ -91,6 +91,18 @@ class JournalEntryController extends Controller
                     'type' => $old['type'][$key],
                     'name' => $old['name'][$key],
                 ];
+
+                // Add supported units for the ingredient.
+                $ingredient = NULL;
+                if ($ingredients[$key]['type'] === Food::class) {
+                    $ingredient = Food::whereId($ingredients[$key]['id'])->first();
+                }
+                elseif ($ingredients[$key]['type'] === Recipe::class) {
+                    $ingredient = Recipe::whereId($ingredients[$key]['id'])->first();
+                }
+                if ($ingredient) {
+                    $ingredients[$key]['units'] = $ingredient->units_supported;
+                }
             }
         }
 
diff --git a/app/JsonApi/Schemas/FoodSchema.php b/app/JsonApi/Schemas/FoodSchema.php
index 8fac8d9..9336d58 100644
--- a/app/JsonApi/Schemas/FoodSchema.php
+++ b/app/JsonApi/Schemas/FoodSchema.php
@@ -43,6 +43,7 @@ class FoodSchema extends SchemaProvider
             'servingUnit' => $resource->serving_unit,
             'servingUnitFormatted' => $resource->serving_unit_formatted,
             'servingWeight' => $resource->serving_weight,
+            'unitsSupported' => $resource->units_supported->pluck('value'),
             'createdAt' => $resource->created_at,
             'updatedAt' => $resource->updated_at,
             'showUrl' => route('foods.show', $resource),
diff --git a/app/JsonApi/Schemas/RecipeSchema.php b/app/JsonApi/Schemas/RecipeSchema.php
index 9dd75b6..b45b80e 100644
--- a/app/JsonApi/Schemas/RecipeSchema.php
+++ b/app/JsonApi/Schemas/RecipeSchema.php
@@ -36,6 +36,7 @@ class RecipeSchema extends SchemaProvider
             'servings' => $resource->servings,
             'weight' => $resource->weight,
             'serving_weight' => $resource->serving_weight,
+            'units_supported' => $resource->units_supported->pluck('label'),
             'caloriesPerServing' => $resource->caloriesPerServing(),
             'carbohydratesPerServing' => $resource->carbohydratesPerServing(),
             'cholesterolPerServing' => $resource->cholesterolPerServing(),
diff --git a/app/Models/Food.php b/app/Models/Food.php
index 618b2e7..8326d18 100644
--- a/app/Models/Food.php
+++ b/app/Models/Food.php
@@ -73,6 +73,7 @@ use Laravel\Scout\Searchable;
  * @mixin \Eloquent
  * @method static \Illuminate\Database\Eloquent\Builder|Food withUniqueSlugConstraints(\Illuminate\Database\Eloquent\Model $model, string $attribute, array $config, string $slug)
  * @method static \Database\Factories\FoodFactory factory(...$parameters)
+ * @property-read \Illuminate\Support\Collection $units_supported
  */
 final class Food extends Model
 {
@@ -129,7 +130,8 @@ final class Food extends Model
      */
     protected $appends = [
         'serving_size_formatted',
-        'serving_unit_formatted'
+        'serving_unit_formatted',
+        'units_supported',
     ];
 
     /**
diff --git a/app/Models/Recipe.php b/app/Models/Recipe.php
index 6184263..6821c20 100644
--- a/app/Models/Recipe.php
+++ b/app/Models/Recipe.php
@@ -77,6 +77,7 @@ use Spatie\MediaLibrary\MediaCollections\Models\Media;
  * @property-read Collection $ingredients_list
  * @property-read \Illuminate\Database\Eloquent\Collection|\App\Models\RecipeSeparator[] $separators
  * @property-read int|null $separators_count
+ * @property-read Collection $units_supported
  */
 final class Recipe extends Model implements HasMedia
 {
@@ -132,6 +133,7 @@ final class Recipe extends Model implements HasMedia
     protected $appends = [
         'serving_weight',
         'time_total',
+        'units_supported'
     ];
 
     /**
diff --git a/app/Models/Traits/Ingredient.php b/app/Models/Traits/Ingredient.php
index c3269b7..a81c339 100644
--- a/app/Models/Traits/Ingredient.php
+++ b/app/Models/Traits/Ingredient.php
@@ -3,8 +3,10 @@
 namespace App\Models\Traits;
 
 use App\Models\IngredientAmount;
-use Illuminate\Database\Eloquent\Collection;
+use App\Support\Nutrients;
+use Illuminate\Database\Eloquent\Collection as DatabaseCollection;
 use Illuminate\Database\Eloquent\Relations\MorphMany;
+use Illuminate\Support\Collection;
 use Illuminate\Support\Facades\DB;
 use Spatie\Tags\Tag;
 
@@ -40,7 +42,7 @@ trait Ingredient
      *
      * @see \Spatie\Tags\HasTags
      */
-    public static function getTagTotals(string $locale = null): Collection {
+    public static function getTagTotals(string $locale = null): DatabaseCollection {
         $locale = $locale ?? app()->getLocale();
         return Tag::query()->join('taggables', 'taggables.tag_id', '=', 'id')
             ->select(['id', 'name', DB::raw('count(*) as total')])
@@ -49,4 +51,20 @@ trait Ingredient
             ->orderBy("name->{$locale}")
             ->get();
     }
+
+    /**
+     * Get a collection of units supported by this ingredient.
+     */
+    public function getUnitsSupportedAttribute(): Collection {
+        $units = Nutrients::units();
+        $supported = $units->where('value', 'serving');
+        if (!empty($this->serving_unit)) {
+            $type = $units->where('value', $this->serving_unit)->pluck('type')->first();
+            $supported = $supported->merge($units->where('type', $type));
+        }
+        if (!empty($this->serving_weight)) {
+            $supported = $supported->merge($units->where('type', 'weight'));
+        }
+        return $supported->sortBy('label');
+    }
 }
diff --git a/app/Models/User.php b/app/Models/User.php
index 11a3248..ee23a60 100644
--- a/app/Models/User.php
+++ b/app/Models/User.php
@@ -38,6 +38,8 @@ use Illuminate\Support\Facades\Auth;
  * @property-read \Illuminate\Database\Eloquent\Collection|\App\Models\Goal[] $goals
  * @property-read int|null $goals_count
  * @method static \Database\Factories\UserFactory factory(...$parameters)
+ * @property-read \Illuminate\Database\Eloquent\Collection|\App\Models\JournalEntry[] $journalEntries
+ * @property-read int|null $journal_entries_count
  */
 final class User extends Authenticatable
 {
diff --git a/app/Support/Nutrients.php b/app/Support/Nutrients.php
index 6cc61c0..6237e71 100644
--- a/app/Support/Nutrients.php
+++ b/app/Support/Nutrients.php
@@ -16,6 +16,7 @@ class Nutrients
      * Each entry has two keys:
      *  - value: Machine name for the unit.
      *  - label: Human-readable name for the unit.
+     *  - type: Unit type -- matching types can be converted.
      *
      * @return \Illuminate\Support\Collection
      */
@@ -23,27 +24,33 @@ class Nutrients
         return new Collection([
             'cup' => [
                 'value' => 'cup',
-                'label' => 'cup'
+                'label' => 'cup',
+                'type' => 'volume',
             ],
             'gram' => [
                 'value' => 'gram',
-                'label' => 'gram'
+                'label' => 'gram',
+                'type' => 'weight',
             ],
             'oz' => [
                 'value' => 'oz',
-                'label' => 'oz'
+                'label' => 'oz',
+                'type' => 'weight',
             ],
             'serving' => [
                 'value' => 'serving',
-                'label' => 'serving'
+                'label' => 'serving',
+                'type' => 'division',
             ],
             'tbsp' => [
                 'value' => 'tbsp',
-                'label' => 'tbsp.'
+                'label' => 'tbsp.',
+                'type' => 'volume',
             ],
             'tsp' => [
                 'value' => 'tsp',
-                'label' => 'tsp.'
+                'label' => 'tsp.',
+                'type' => 'volume',
             ],
         ]);
     }
diff --git a/resources/views/journal-entries/partials/entry-item-input.blade.php b/resources/views/journal-entries/partials/entry-item-input.blade.php
index 1f79a26..bc120ee 100644
--- a/resources/views/journal-entries/partials/entry-item-input.blade.php
+++ b/resources/views/journal-entries/partials/entry-item-input.blade.php
@@ -46,7 +46,7 @@
                 <x-inputs.label for="ingredients[unit][]" value="Unit" class="md:hidden"/>
                 <x-inputs.select name="ingredients[unit][]"
                                  class="block w-full"
-                                 :options="$units"
+                                 :options="$units ?? []"
                                  :selectedValue="$unit ?? null">
                     <option value="">-- Unit --</option>
                 </x-inputs.select>
@@ -74,7 +74,20 @@
             window.addEventListener('ingredient-picked', (e) => {
                 const entryItem = e.target.closest('.entry-item');
                 const ingredient = e.detail.ingredient;
-                let servingSize, servingUnit;
+                let servingSize, servingUnit
+
+                // Restrict unit select list values to supported units.
+                const unitsSelectList = entryItem.querySelector(':scope select[name="ingredients[unit][]"]');
+                for (const [key, option] in unitsSelectList.options) {
+                    unitsSelectList.remove(key);
+                }
+                for (const key in ingredient.units_supported) {
+                    const unit = ingredient.units_supported[key];
+                    const option = document.createElement('option');
+                    option.value = unit.value;
+                    option.text = unit.label;
+                    unitsSelectList.add(option);
+                }
 
                 // Always set recipes to a default of 1 serving.
                 if (ingredient.type === 'App\\Models\\Recipe') {