diff --git a/docs/content/docs/1.getting-started/3.migration/1.v4.md b/docs/content/docs/1.getting-started/3.migration/1.v4.md
index b7a9c58e15..9e2db6e09e 100644
--- a/docs/content/docs/1.getting-started/3.migration/1.v4.md
+++ b/docs/content/docs/1.getting-started/3.migration/1.v4.md
@@ -352,3 +352,24 @@ For more details on AI SDK v5 changes, review the **official AI SDK v5 migration
 ::tip{to="https://github.com/nuxt/ui/pull/4698" target="_blank"}
 View all changes from AI SDK v4 to v5 **in the upgrade PR** for a detailed migration reference.
 ::
+
+### Updated `modelModifiers` for `UInput` and `UTextarea`
+
+The `modelModifiers` shape used by `UInput` and `UTextarea` has changed in v4:
+
+- The `nullify` modifier was renamed to `nullable` (it converts empty/blank values to `null`).
+- A new `optional` modifier was added (it converts empty/blank values to `undefined`).
+
+Examples:
+
+```diff
+- <UInput v-model.nullify="value" />
++ <UInput v-model.nullable="value" />
+```
+
+```diff
+- <UTextarea v-model="value" :model-modifiers="{ nullify: true }" />
++ <UTextarea v-model="value" :model-modifiers="{ nullable: true }" />
+```
+
+Use `nullable` when you want empty values as `null`, and `optional` when you prefer `undefined` for absent values.
diff --git a/src/runtime/components/Input.vue b/src/runtime/components/Input.vue
index 43d57ae382..35bcbc1706 100644
--- a/src/runtime/components/Input.vue
+++ b/src/runtime/components/Input.vue
@@ -4,6 +4,7 @@ import type { AppConfig } from '@nuxt/schema'
 import theme from '#build/ui/input'
 import type { UseComponentIconsProps } from '../composables/useComponentIcons'
 import type { AvatarProps } from '../types'
+import type { ModelModifiers } from '../types/input'
 import type { AcceptableValue } from '../types/utils'
 import type { ComponentConfig } from '../types/tv'
 
@@ -41,13 +42,7 @@ export interface InputProps<T extends AcceptableValue = AcceptableValue> extends
   highlight?: boolean
   modelValue?: T
   defaultValue?: T
-  modelModifiers?: {
-    string?: boolean
-    number?: boolean
-    trim?: boolean
-    lazy?: boolean
-    nullify?: boolean
-  }
+  modelModifiers?: ModelModifiers
   class?: any
   ui?: Input['slots']
 }
@@ -113,7 +108,7 @@ const ui = computed(() => tv({ extend: tv(theme), ...(appConfig.ui?.input || {})
 const inputRef = ref<HTMLInputElement | null>(null)
 
 // Custom function to handle the v-model properties
-function updateInput(value: string | null) {
+function updateInput(value: string | null | undefined) {
   if (props.modelModifiers?.trim) {
     value = value?.trim() ?? null
   }
@@ -122,10 +117,14 @@ function updateInput(value: string | null) {
     value = looseToNumber(value)
   }
 
-  if (props.modelModifiers?.nullify) {
+  if (props.modelModifiers?.nullable) {
     value ||= null
   }
 
+  if (props.modelModifiers?.optional) {
+    value ||= undefined
+  }
+
   modelValue.value = value as T
   emitFormInput()
 }
diff --git a/src/runtime/components/InputNumber.vue b/src/runtime/components/InputNumber.vue
index ec790ff163..4fc119a2c9 100644
--- a/src/runtime/components/InputNumber.vue
+++ b/src/runtime/components/InputNumber.vue
@@ -3,6 +3,7 @@ import type { NumberFieldRootProps } from 'reka-ui'
 import type { AppConfig } from '@nuxt/schema'
 import theme from '#build/ui/input-number'
 import type { ButtonProps, IconProps } from '../types'
+import type { ModelModifiers } from '../types/input'
 import type { ComponentConfig } from '../types/tv'
 
 type InputNumber = ComponentConfig<typeof theme, AppConfig, 'inputNumber'>
@@ -53,6 +54,9 @@ export interface InputNumberProps extends Pick<NumberFieldRootProps, 'modelValue
   decrementDisabled?: boolean
   autofocus?: boolean
   autofocusDelay?: number
+  modelValue?: number
+  defaultValue?: number
+  modelModifiers?: Pick<ModelModifiers, 'optional'>
   /**
    * The locale to use for formatting and parsing numbers.
    * @defaultValue UApp.locale.code
@@ -77,7 +81,7 @@ export interface InputNumberSlots {
 <script setup lang="ts">
 import { onMounted, ref, computed } from 'vue'
 import { NumberFieldRoot, NumberFieldInput, NumberFieldDecrement, NumberFieldIncrement, useForwardPropsEmits } from 'reka-ui'
-import { reactivePick } from '@vueuse/core'
+import { reactivePick, useVModel } from '@vueuse/core'
 import { useAppConfig } from '#imports'
 import { useFieldGroup } from '../composables/useFieldGroup'
 import { useFormField } from '../composables/useFormField'
@@ -95,10 +99,12 @@ const props = withDefaults(defineProps<InputNumberProps>(), {
 const emits = defineEmits<InputNumberEmits>()
 defineSlots<InputNumberSlots>()
 
+const modelValue = useVModel<InputNumberProps, 'modelValue', 'update:modelValue'>(props, 'modelValue', emits, { defaultValue: props.defaultValue })
+
 const { t, code: codeLocale } = useLocale()
 const appConfig = useAppConfig() as InputNumber['AppConfig']
 
-const rootProps = useForwardPropsEmits(reactivePick(props, 'as', 'modelValue', 'defaultValue', 'min', 'max', 'step', 'stepSnapping', 'formatOptions', 'disableWheelChange', 'invertWheelChange', 'readonly'), emits)
+const rootProps = useForwardPropsEmits(reactivePick(props, 'as', 'defaultValue', 'min', 'max', 'step', 'stepSnapping', 'formatOptions', 'disableWheelChange', 'invertWheelChange', 'readonly'), emits)
 
 const { emitFormBlur, emitFormFocus, emitFormChange, emitFormInput, id, color, size: formGroupSize, name, highlight, disabled, ariaAttrs } = useFormField<InputNumberProps>(props)
 const { orientation, size: fieldGroupSize } = useFieldGroup<InputNumberProps>(props)
@@ -120,7 +126,11 @@ const decrementIcon = computed(() => props.decrementIcon || (props.orientation =
 
 const inputRef = ref<InstanceType<typeof NumberFieldInput> | null>(null)
 
-function onUpdate(value: number) {
+function onUpdate(value: number | undefined) {
+  if (props.modelModifiers?.optional) {
+    value = value ?? undefined
+  }
+
   // @ts-expect-error - 'target' does not exist in type 'EventInit'
   const event = new Event('change', { target: { value } })
   emits('change', event)
@@ -155,6 +165,7 @@ defineExpose({
   <NumberFieldRoot
     v-bind="rootProps"
     :id="id"
+    :model-value="modelValue"
     :class="ui.root({ class: [props.ui?.root, props.class] })"
     :name="name"
     :disabled="disabled"
diff --git a/src/runtime/components/Textarea.vue b/src/runtime/components/Textarea.vue
index 7e9d4efb87..d65f8cd5fe 100644
--- a/src/runtime/components/Textarea.vue
+++ b/src/runtime/components/Textarea.vue
@@ -3,6 +3,7 @@ import type { AppConfig } from '@nuxt/schema'
 import theme from '#build/ui/textarea'
 import type { UseComponentIconsProps } from '../composables/useComponentIcons'
 import type { AvatarProps } from '../types'
+import type { ModelModifiers } from '../types/input'
 import type { ComponentConfig } from '../types/tv'
 
 type Textarea = ComponentConfig<typeof theme, AppConfig, 'textarea'>
@@ -43,13 +44,7 @@ export interface TextareaProps<T extends TextareaValue = TextareaValue> extends
   highlight?: boolean
   modelValue?: T
   defaultValue?: T
-  modelModifiers?: {
-    string?: boolean
-    number?: boolean
-    trim?: boolean
-    lazy?: boolean
-    nullify?: boolean
-  }
+  modelModifiers?: ModelModifiers
   class?: any
   ui?: Textarea['slots']
 }
@@ -111,7 +106,7 @@ const ui = computed(() => tv({ extend: tv(theme), ...(appConfig.ui?.textarea ||
 const textareaRef = ref<HTMLTextAreaElement | null>(null)
 
 // Custom function to handle the v-model properties
-function updateInput(value: string | null) {
+function updateInput(value: string | null | undefined) {
   if (props.modelModifiers?.trim) {
     value = value?.trim() ?? null
   }
@@ -120,10 +115,14 @@ function updateInput(value: string | null) {
     value = looseToNumber(value)
   }
 
-  if (props.modelModifiers?.nullify) {
+  if (props.modelModifiers?.nullable) {
     value ||= null
   }
 
+  if (props.modelModifiers?.optional) {
+    value ||= undefined
+  }
+
   modelValue.value = value as T
   emitFormInput()
 }
diff --git a/src/runtime/types/input.ts b/src/runtime/types/input.ts
new file mode 100644
index 0000000000..55430140cf
--- /dev/null
+++ b/src/runtime/types/input.ts
@@ -0,0 +1,8 @@
+export interface ModelModifiers {
+  string?: boolean
+  number?: boolean
+  trim?: boolean
+  lazy?: boolean
+  nullable?: boolean
+  optional?: boolean
+}
diff --git a/test/components/Input.spec.ts b/test/components/Input.spec.ts
index 0824767977..76cace4db9 100644
--- a/test/components/Input.spec.ts
+++ b/test/components/Input.spec.ts
@@ -54,7 +54,8 @@ describe('Input', () => {
     ['with .trim modifier', { props: { modelModifiers: { trim: true } } }, { input: 'input  ', expected: 'input' }],
     ['with .number modifier', { props: { modelModifiers: { number: true } } }, { input: '42', expected: 42 }],
     ['with .lazy modifier', { props: { modelModifiers: { lazy: true } } }, { input: 'input', expected: 'input' }],
-    ['with .nullify modifier', { props: { modelModifiers: { nullify: true } } }, { input: '', expected: null }]
+    ['with .nullable modifier', { props: { modelModifiers: { nullable: true } } }, { input: '', expected: null }],
+    ['with .optional modifier', { props: { modelModifiers: { optional: true } } }, { input: '', expected: undefined }]
   ])('%s works', async (_nameOrHtml: string, options: { props?: any, slots?: any }, spec: { input: any, expected: any }) => {
     const wrapper = mount(Input, {
       ...options
diff --git a/test/components/InputNumber.spec.ts b/test/components/InputNumber.spec.ts
index f1287910a1..f7a8e229a8 100644
--- a/test/components/InputNumber.spec.ts
+++ b/test/components/InputNumber.spec.ts
@@ -29,6 +29,7 @@ describe('InputNumber', () => {
     ['with as', { props: { as: 'section' } }],
     ['with class', { props: { class: 'absolute' } }],
     ['with ui', { props: { ui: { base: 'rounded-full' } } }],
+    ['with .optional modifier', { props: { modelModifiers: { optional: true } } }, { input: '', expected: undefined }],
     // Slots
     ['with increment slot', { slots: { increment: () => '+' } }],
     ['with decrement slot', { slots: { decrement: () => '-' } }]
diff --git a/test/components/Textarea.spec.ts b/test/components/Textarea.spec.ts
index a57a7470e6..abe0eb3aae 100644
--- a/test/components/Textarea.spec.ts
+++ b/test/components/Textarea.spec.ts
@@ -53,7 +53,8 @@ describe('Textarea', () => {
     ['with .trim modifier', { props: { modelModifiers: { trim: true } } }, { input: 'input  ', expected: 'input' }],
     ['with .number modifier', { props: { modelModifiers: { number: true } } }, { input: '42', expected: 42 }],
     ['with .lazy modifier', { props: { modelModifiers: { lazy: true } } }, { input: 'input', expected: 'input' }],
-    ['with .nullify modifier', { props: { modelModifiers: { nullify: true } } }, { input: '', expected: null }]
+    ['with .nullable modifier', { props: { modelModifiers: { nullable: true } } }, { input: '', expected: null }],
+    ['with .optional modifier', { props: { modelModifiers: { optional: true } } }, { input: '', expected: undefined }]
   ])('%s works', async (_nameOrHtml: string, options: { props?: any, slots?: any }, spec: { input: any, expected: any }) => {
     const wrapper = mount(Textarea, {
       ...options
diff --git a/test/components/__snapshots__/InputNumber-vue.spec.ts.snap b/test/components/__snapshots__/InputNumber-vue.spec.ts.snap
index 6cd1d6bbf3..f49d7f68ae 100644
--- a/test/components/__snapshots__/InputNumber-vue.spec.ts.snap
+++ b/test/components/__snapshots__/InputNumber-vue.spec.ts.snap
@@ -1,5 +1,19 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
+exports[`InputNumber > renders with .optional modifier correctly 1`] = `
+"<div class="relative inline-flex items-center" role="group"><input role="spinbutton" type="text" tabindex="0" inputmode="decimal" autocomplete="off" autocorrect="off" spellcheck="false" aria-roledescription="Number field" class="w-full rounded-md border-0 placeholder:text-dimmed focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented text-center focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary px-9" value="">
+  <div class="absolute flex items-center inset-y-0 end-0 pe-1"><button type="button" tabindex="-1" aria-label="Increment" class="rounded-md font-medium inline-flex items-center disabled:cursor-not-allowed aria-disabled:cursor-not-allowed disabled:opacity-75 aria-disabled:opacity-75 transition-colors text-sm gap-1.5 text-primary hover:text-primary/75 active:text-primary/75 disabled:text-primary aria-disabled:text-primary focus:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary p-1.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 size-5"></svg>
+      <!--v-if-->
+      <!--v-if-->
+    </button></div>
+  <div class="absolute flex items-center inset-y-0 start-0 ps-1"><button type="button" tabindex="-1" aria-label="Decrement" class="rounded-md font-medium inline-flex items-center disabled:cursor-not-allowed aria-disabled:cursor-not-allowed disabled:opacity-75 aria-disabled:opacity-75 transition-colors text-sm gap-1.5 text-primary hover:text-primary/75 active:text-primary/75 disabled:text-primary aria-disabled:text-primary focus:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary p-1.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 size-5"></svg>
+      <!--v-if-->
+      <!--v-if-->
+    </button></div>
+  <!--v-if-->
+</div>"
+`;
+
 exports[`InputNumber > renders with ariaLabel correctly 1`] = `
 "<div class="relative inline-flex items-center" role="group"><input role="spinbutton" type="text" tabindex="0" inputmode="decimal" autocomplete="off" autocorrect="off" spellcheck="false" aria-roledescription="Number field" aria-label="Aria label" class="w-full rounded-md border-0 placeholder:text-dimmed focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented text-center focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary px-9" value="">
   <div class="absolute flex items-center inset-y-0 end-0 pe-1"><button type="button" tabindex="-1" aria-label="Increment" class="rounded-md font-medium inline-flex items-center disabled:cursor-not-allowed aria-disabled:cursor-not-allowed disabled:opacity-75 aria-disabled:opacity-75 transition-colors text-sm gap-1.5 text-primary hover:text-primary/75 active:text-primary/75 disabled:text-primary aria-disabled:text-primary focus:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary p-1.5"><svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" aria-hidden="true" role="img" width="1em" height="1em" viewBox="0 0 16 16" class="shrink-0 size-5"></svg>
diff --git a/test/components/__snapshots__/InputNumber.spec.ts.snap b/test/components/__snapshots__/InputNumber.spec.ts.snap
index b75b05d722..5e287de339 100644
--- a/test/components/__snapshots__/InputNumber.spec.ts.snap
+++ b/test/components/__snapshots__/InputNumber.spec.ts.snap
@@ -1,5 +1,19 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
+exports[`InputNumber > renders with .optional modifier correctly 1`] = `
+"<div class="relative inline-flex items-center" role="group"><input role="spinbutton" type="text" tabindex="0" inputmode="decimal" autocomplete="off" autocorrect="off" spellcheck="false" aria-roledescription="Number field" class="w-full rounded-md border-0 placeholder:text-dimmed focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented text-center focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary px-9" value="">
+  <div class="absolute flex items-center inset-y-0 end-0 pe-1"><button type="button" tabindex="-1" aria-label="Increment" class="rounded-md font-medium inline-flex items-center disabled:cursor-not-allowed aria-disabled:cursor-not-allowed disabled:opacity-75 aria-disabled:opacity-75 transition-colors text-sm gap-1.5 text-primary hover:text-primary/75 active:text-primary/75 disabled:text-primary aria-disabled:text-primary focus:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary p-1.5"><span class="iconify i-lucide:plus shrink-0 size-5" aria-hidden="true"></span>
+      <!--v-if-->
+      <!--v-if-->
+    </button></div>
+  <div class="absolute flex items-center inset-y-0 start-0 ps-1"><button type="button" tabindex="-1" aria-label="Decrement" class="rounded-md font-medium inline-flex items-center disabled:cursor-not-allowed aria-disabled:cursor-not-allowed disabled:opacity-75 aria-disabled:opacity-75 transition-colors text-sm gap-1.5 text-primary hover:text-primary/75 active:text-primary/75 disabled:text-primary aria-disabled:text-primary focus:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary p-1.5"><span class="iconify i-lucide:minus shrink-0 size-5" aria-hidden="true"></span>
+      <!--v-if-->
+      <!--v-if-->
+    </button></div>
+  <!--v-if-->
+</div>"
+`;
+
 exports[`InputNumber > renders with ariaLabel correctly 1`] = `
 "<div class="relative inline-flex items-center" role="group"><input role="spinbutton" type="text" tabindex="0" inputmode="decimal" autocomplete="off" autocorrect="off" spellcheck="false" aria-roledescription="Number field" aria-label="Aria label" class="w-full rounded-md border-0 placeholder:text-dimmed focus:outline-none disabled:cursor-not-allowed disabled:opacity-75 transition-colors py-1.5 text-sm gap-1.5 text-highlighted bg-default ring ring-inset ring-accented text-center focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary px-9" value="">
   <div class="absolute flex items-center inset-y-0 end-0 pe-1"><button type="button" tabindex="-1" aria-label="Increment" class="rounded-md font-medium inline-flex items-center disabled:cursor-not-allowed aria-disabled:cursor-not-allowed disabled:opacity-75 aria-disabled:opacity-75 transition-colors text-sm gap-1.5 text-primary hover:text-primary/75 active:text-primary/75 disabled:text-primary aria-disabled:text-primary focus:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-primary p-1.5"><span class="iconify i-lucide:plus shrink-0 size-5" aria-hidden="true"></span>