diff --git a/app/assets/javascripts/admin/addon/components/file-size-input.gjs b/app/assets/javascripts/admin/addon/components/file-size-input.gjs
new file mode 100644
index 00000000000..77df855b90c
--- /dev/null
+++ b/app/assets/javascripts/admin/addon/components/file-size-input.gjs
@@ -0,0 +1,150 @@
+import Component from "@glimmer/component";
+import { tracked } from "@glimmer/tracking";
+import { on } from "@ember/modifier";
+import { action } from "@ember/object";
+import didInsert from "@ember/render-modifiers/modifiers/did-insert";
+import didUpdate from "@ember/render-modifiers/modifiers/did-update";
+import TextField from "discourse/components/text-field";
+import { allowOnlyNumericInput } from "discourse/lib/utilities";
+import I18n from "discourse-i18n";
+import ComboBox from "select-kit/components/combo-box";
+
+const UNIT_KB = "kb";
+const UNIT_MB = "mb";
+const UNIT_GB = "gb";
+
+export default class FileSizeInput extends Component {
+  @tracked fileSizeUnit;
+  @tracked sizeValue;
+  @tracked pendingSizeValue;
+  @tracked pendingFileSizeUnit;
+
+  constructor(owner, args) {
+    super(owner, args);
+    this.originalSizeKB = this.args.sizeValueKB;
+    this.sizeValue = this.args.sizeValueKB;
+
+    this._defaultUnit();
+  }
+
+  _defaultUnit() {
+    this.fileSizeUnit = UNIT_KB;
+    if (this.originalSizeKB <= 1024) {
+      this.onFileSizeUnitChange(UNIT_KB);
+    } else if (
+      this.originalSizeKB > 1024 &&
+      this.originalSizeKB <= 1024 * 1024
+    ) {
+      this.onFileSizeUnitChange(UNIT_MB);
+    } else if (this.originalSizeKB > 1024 * 1024) {
+      this.onFileSizeUnitChange(UNIT_GB);
+    }
+  }
+
+  @action
+  keyDown(event) {
+    allowOnlyNumericInput(event);
+  }
+
+  get dropdownOptions() {
+    return [
+      { label: I18n.t("number.human.storage_units.units.kb"), value: UNIT_KB },
+      { label: I18n.t("number.human.storage_units.units.mb"), value: UNIT_MB },
+      { label: I18n.t("number.human.storage_units.units.gb"), value: UNIT_GB },
+    ];
+  }
+
+  @action
+  handleFileSizeChange(value) {
+    if (value !== "") {
+      this.pendingSizeValue = value;
+      this._onFileSizeChange(value);
+    }
+  }
+
+  _onFileSizeChange(newSize) {
+    let fileSizeKB;
+    switch (this.fileSizeUnit) {
+      case "kb":
+        fileSizeKB = newSize;
+        break;
+      case "mb":
+        fileSizeKB = newSize * 1024;
+        break;
+      case "gb":
+        fileSizeKB = newSize * 1024 * 1024;
+        break;
+    }
+    if (fileSizeKB > this.args.max) {
+      this.args.updateValidationMessage(
+        I18n.t("file_size_input.error.size_too_large", {
+          provided_file_size: I18n.toHumanSize(fileSizeKB * 1024),
+          max_file_size: I18n.toHumanSize(this.args.max * 1024),
+        })
+      );
+      // Removes the green save checkmark button
+      this.args.onChangeSize(this.originalSizeKB);
+    } else {
+      this.args.onChangeSize(fileSizeKB);
+      this.args.updateValidationMessage(null);
+    }
+  }
+
+  @action
+  onFileSizeUnitChange(newUnit) {
+    if (this.fileSizeUnit === "kb" && newUnit === "kb") {
+      this.pendingSizeValue = this.sizeValue;
+    }
+    if (this.fileSizeUnit === "kb" && newUnit === "mb") {
+      this.pendingSizeValue = this.sizeValue / 1024;
+    }
+    if (this.fileSizeUnit === "kb" && newUnit === "gb") {
+      this.pendingSizeValue = this.sizeValue / 1024 / 1024;
+    }
+    if (this.fileSizeUnit === "mb" && newUnit === "kb") {
+      this.pendingSizeValue = this.sizeValue * 1024;
+    }
+    if (this.fileSizeUnit === "mb" && newUnit === "gb") {
+      this.pendingSizeValue = this.sizeValue / 1024;
+    }
+    if (this.fileSizeUnit === "gb" && newUnit === "mb") {
+      this.pendingSizeValue = this.sizeValue * 1024;
+    }
+    if (this.fileSizeUnit === "gb" && newUnit === "kb") {
+      this.pendingSizeValue = this.sizeValue * 1024 * 1024;
+    }
+    this.pendingFileSizeUnit = newUnit;
+  }
+
+  @action
+  applySizeValueChanges() {
+    this.sizeValue = this.pendingSizeValue;
+  }
+
+  @action
+  applyUnitChanges() {
+    this.fileSizeUnit = this.pendingFileSizeUnit;
+  }
+
+  <template>
+    <div class="file-size-picker">
+      <TextField
+        class="file-size-input"
+        @value={{this.sizeValue}}
+        @onChange={{this.handleFileSizeChange}}
+        {{on "keydown" this.keyDown}}
+        {{didInsert this.applySizeValueChanges}}
+        {{didUpdate this.applySizeValueChanges this.pendingSizeValue}}
+      />
+      <ComboBox
+        class="file-size-unit-selector"
+        @valueProperty="value"
+        @content={{this.dropdownOptions}}
+        @value={{this.fileSizeUnit}}
+        @onChange={{this.onFileSizeUnitChange}}
+        {{didInsert this.applyUnitChanges}}
+        {{didUpdate this.applyUnitChanges this.pendingFileSizeUnit}}
+      />
+    </div>
+  </template>
+}
diff --git a/app/assets/javascripts/admin/addon/components/site-settings/file-size-restriction.gjs b/app/assets/javascripts/admin/addon/components/site-settings/file-size-restriction.gjs
new file mode 100644
index 00000000000..9ec64ed6eff
--- /dev/null
+++ b/app/assets/javascripts/admin/addon/components/site-settings/file-size-restriction.gjs
@@ -0,0 +1,34 @@
+import Component from "@glimmer/component";
+import { tracked } from "@glimmer/tracking";
+import { fn } from "@ember/helper";
+import { action } from "@ember/object";
+import { htmlSafe } from "@ember/template";
+import FileSizeInput from "admin/components/file-size-input";
+import SettingValidationMessage from "admin/components/setting-validation-message";
+
+export default class FileSizeRestriction extends Component {
+  @tracked _validationMessage = this.args.validationMessage;
+
+  @action
+  updateValidationMessage(message) {
+    this._validationMessage = message;
+  }
+
+  get validationMessage() {
+    return this._validationMessage ?? this.args.validationMessage;
+  }
+
+  <template>
+    <FileSizeInput
+      @sizeValueKB={{@value}}
+      @onChangeSize={{fn (mut @value)}}
+      @updateValidationMessage={{this.updateValidationMessage}}
+      @min={{if @setting.min @setting.min null}}
+      @max={{if @setting.max @setting.max null}}
+      @message={{this.validationMessage}}
+    />
+
+    <SettingValidationMessage @message={{this.validationMessage}} />
+    <div class="desc">{{htmlSafe @setting.description}}</div>
+  </template>
+}
diff --git a/app/assets/javascripts/admin/addon/mixins/setting-component.js b/app/assets/javascripts/admin/addon/mixins/setting-component.js
index ab24c65993f..bb7b8e66317 100644
--- a/app/assets/javascripts/admin/addon/mixins/setting-component.js
+++ b/app/assets/javascripts/admin/addon/mixins/setting-component.js
@@ -33,6 +33,7 @@ const CUSTOM_TYPES = [
   "simple_list",
   "emoji_list",
   "named_list",
+  "file_size_restriction",
 ];
 
 const AUTO_REFRESH_ON_SAVE = ["logo", "logo_small", "large_icon"];
diff --git a/app/assets/javascripts/discourse/app/components/number-field.js b/app/assets/javascripts/discourse/app/components/number-field.js
index 38838358ef8..c5236ca169a 100644
--- a/app/assets/javascripts/discourse/app/components/number-field.js
+++ b/app/assets/javascripts/discourse/app/components/number-field.js
@@ -1,36 +1,13 @@
 import TextField from "discourse/components/text-field";
+import { allowOnlyNumericInput } from "discourse/lib/utilities";
 import discourseComputed from "discourse-common/utils/decorators";
 import I18n from "discourse-i18n";
 
-const ALLOWED_KEYS = [
-  "Enter",
-  "Backspace",
-  "Tab",
-  "Delete",
-  "ArrowLeft",
-  "ArrowUp",
-  "ArrowRight",
-  "ArrowDown",
-  "0",
-  "1",
-  "2",
-  "3",
-  "4",
-  "5",
-  "6",
-  "7",
-  "8",
-  "9",
-];
-
 export default TextField.extend({
   classNameBindings: ["invalid"],
 
   keyDown: function (event) {
-    return (
-      ALLOWED_KEYS.includes(event.key) ||
-      (event.key === "-" && this._minNumber && this._minNumber < 0)
-    );
+    allowOnlyNumericInput(event, this._minNumber && this._minNumber < 0);
   },
 
   get _minNumber() {
diff --git a/app/assets/javascripts/discourse/app/lib/utilities.js b/app/assets/javascripts/discourse/app/lib/utilities.js
index 1b5903f045b..f666147a2a1 100644
--- a/app/assets/javascripts/discourse/app/lib/utilities.js
+++ b/app/assets/javascripts/discourse/app/lib/utilities.js
@@ -693,3 +693,34 @@ export function tokenRange(tokens, start, end) {
 
   return contents;
 }
+
+export function allowOnlyNumericInput(event, allowNegative = false) {
+  const ALLOWED_KEYS = [
+    "Enter",
+    "Backspace",
+    "Tab",
+    "Delete",
+    "ArrowLeft",
+    "ArrowUp",
+    "ArrowRight",
+    "ArrowDown",
+    "0",
+    "1",
+    "2",
+    "3",
+    "4",
+    "5",
+    "6",
+    "7",
+    "8",
+    "9",
+  ];
+
+  if (!ALLOWED_KEYS.includes(event.key)) {
+    if (allowNegative && event.key === "-") {
+      return;
+    } else {
+      event.preventDefault();
+    }
+  }
+}
diff --git a/app/assets/javascripts/discourse/tests/integration/components/file-size-input-test.js b/app/assets/javascripts/discourse/tests/integration/components/file-size-input-test.js
new file mode 100644
index 00000000000..1305c3e9d91
--- /dev/null
+++ b/app/assets/javascripts/discourse/tests/integration/components/file-size-input-test.js
@@ -0,0 +1,128 @@
+import { click, fillIn, render } from "@ember/test-helpers";
+import { hbs } from "ember-cli-htmlbars";
+import { module, test } from "qunit";
+import { setupRenderingTest } from "discourse/tests/helpers/component-test";
+import selectKit from "discourse/tests/helpers/select-kit-helper";
+
+module("Integration | Component | file-size-input", function (hooks) {
+  setupRenderingTest(hooks);
+
+  test("file size unit selector kb", async function (assert) {
+    this.set("value", 1024);
+    this.set("max", 4096);
+    this.set("onChangeSize", () => {});
+    this.set("updateValidationMessage", () => {});
+
+    await render(hbs`
+      <FileSizeInput
+        @sizeValueKB={{readonly this.value}}
+        class="file-size-input-test"
+        @onChangeSize={{this.onChangeSize}}
+        @updateValidationMessage={{this.updateValidationMessage}}
+        @max=4096
+        @message=""
+      />
+    `);
+
+    assert.dom(".file-size-input").hasValue("1024", "value is present");
+  });
+
+  test("file size unit selector", async function (assert) {
+    this.set("value", 4096);
+    this.set("max", 8192);
+    this.set("onChangeSize", () => {});
+    this.set("updateValidationMessage", () => {});
+
+    await render(hbs`
+      <FileSizeInput
+        @sizeValueKB={{readonly this.value}}
+        class="file-size-input-test"
+        @onChangeSize={{this.onChangeSize}}
+        @updateValidationMessage={{this.updateValidationMessage}}
+        @max=4096
+        @message=""
+      />
+    `);
+
+    await click(".file-size-unit-selector");
+
+    await selectKit(".file-size-unit-selector").expand();
+    await selectKit(".file-size-unit-selector").selectRowByValue("kb");
+
+    assert
+      .dom(".file-size-input")
+      .hasValue("4096", "value is change when then unit is changed");
+
+    await click(".file-size-unit-selector");
+
+    await selectKit(".file-size-unit-selector").expand();
+    await selectKit(".file-size-unit-selector").selectRowByValue("mb");
+
+    assert
+      .dom(".file-size-input")
+      .hasValue("4", "value is changed when the unit is changed");
+
+    await click(".file-size-unit-selector");
+
+    await selectKit(".file-size-unit-selector").expand();
+    await selectKit(".file-size-unit-selector").selectRowByValue("gb");
+
+    // TODO: Implement rounding or limit to X digits.
+    assert
+      .dom(".file-size-input")
+      .hasValue(
+        "0.00390625",
+        "value is changed when the unit is changed to gb"
+      );
+
+    await click(".file-size-unit-selector");
+
+    await selectKit(".file-size-unit-selector").expand();
+    await selectKit(".file-size-unit-selector").selectRowByValue("mb");
+
+    assert
+      .dom(".file-size-input")
+      .hasValue(
+        "4",
+        "value is changed backed to original size with no decimal places"
+      );
+  });
+
+  test("file size input error message", async function (assert) {
+    this.set("value", 4096);
+    this.set("max", 8192);
+    this.set("onChangeSize", () => {});
+
+    let updateValidationMessage = (message) => {
+      this.set("message", message);
+    };
+    this.set("updateValidationMessage", updateValidationMessage);
+
+    await render(hbs`
+      <FileSizeInput
+        @sizeValueKB={{readonly this.value}}
+        class="file-size-input-test"
+        @onChangeSize={{this.onChangeSize}}
+        @updateValidationMessage={{this.updateValidationMessage}}
+        @max={{this.max}}
+        @message={{this.message}}
+      />
+    `);
+
+    await fillIn(".file-size-input", 12);
+
+    assert.strictEqual(
+      this.message,
+      "12 MB is greater than the max allowed 8 MB",
+      "A message is showed when the input is greater than the max"
+    );
+
+    await fillIn(".file-size-input", 4);
+
+    assert.strictEqual(
+      this.message,
+      null,
+      "The message is cleared when the input is less than the max"
+    );
+  });
+});
diff --git a/app/assets/stylesheets/common/components/_index.scss b/app/assets/stylesheets/common/components/_index.scss
index 2b232752df9..c59c6645d37 100644
--- a/app/assets/stylesheets/common/components/_index.scss
+++ b/app/assets/stylesheets/common/components/_index.scss
@@ -14,6 +14,7 @@
 @import "date-picker";
 @import "date-time-input-range";
 @import "date-time-input";
+@import "file-size-input";
 @import "footer-nav";
 @import "form-template-field";
 @import "group-member-dropdown";
diff --git a/app/assets/stylesheets/common/components/file-size-input.scss b/app/assets/stylesheets/common/components/file-size-input.scss
new file mode 100644
index 00000000000..00cb90587f4
--- /dev/null
+++ b/app/assets/stylesheets/common/components/file-size-input.scss
@@ -0,0 +1,15 @@
+.file-size-picker {
+  display: flex;
+
+  .file-size-input {
+    flex: 1;
+  }
+
+  .file-size-unit-selector {
+    flex: 0 0 8em;
+  }
+
+  .select-kit .select-kit-header {
+    border-left: 0;
+  }
+}
diff --git a/app/controllers/admin/site_settings_controller.rb b/app/controllers/admin/site_settings_controller.rb
index fe75884edc2..ba3054abde3 100644
--- a/app/controllers/admin/site_settings_controller.rb
+++ b/app/controllers/admin/site_settings_controller.rb
@@ -34,6 +34,8 @@ class Admin::SiteSettingsController < Admin::AdminController
     case SiteSetting.type_supervisor.get_type(id)
     when :integer
       value = value.tr("^-0-9", "")
+    when :file_size_restriction
+      value = value.tr("^-0-9", "")
     when :uploaded_image_list
       value = Upload.get_from_urls(value.split("|")).to_a
     end
diff --git a/config/locales/client.en.yml b/config/locales/client.en.yml
index ba25786bfcb..6457cb9a1c2 100644
--- a/config/locales/client.en.yml
+++ b/config/locales/client.en.yml
@@ -2348,6 +2348,10 @@ en:
       from: From
       to: To
 
+    file_size_input:
+      error:
+        size_too_large: "%{provided_file_size} is greater than the max allowed %{max_file_size}"
+
     emoji_picker:
       filter_placeholder: Search for emoji
       smileys_&_emotion: Smileys and Emotion
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 859c64510b3..664f1ea7581 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -2017,8 +2017,8 @@ en:
     default_dark_mode_color_scheme_id: "The color scheme used when in dark mode."
     dark_mode_none: "None"
 
-    max_image_size_kb: "The maximum image upload size in kB. This must be configured in nginx (client_max_body_size) / apache or proxy as well. Images larger than this and smaller than client_max_body_size will be resized to fit on upload."
-    max_attachment_size_kb: "The maximum attachment files upload size in kB. This must be configured in nginx (client_max_body_size) / apache or proxy as well."
+    max_image_size_kb: "The maximum image upload size. This must be configured in nginx (client_max_body_size) / apache or proxy as well. Images larger than this and smaller than client_max_body_size will be resized to fit on upload."
+    max_attachment_size_kb: "The maximum attachment files upload size. This must be configured in nginx (client_max_body_size) / apache or proxy as well."
     authorized_extensions: "A list of file extensions allowed for upload (use '*' to enable all file types)"
     authorized_extensions_for_staff: "A list of file extensions allowed for upload for staff users in addition to the list defined in the `authorized_extensions` site setting. (use '*' to enable all file types)"
     theme_authorized_extensions: "A list of file extensions allowed for theme uploads (use '*' to enable all file types)"
@@ -2125,7 +2125,7 @@ en:
     always_show_trimmed_content: "Always show trimmed part of incoming emails. WARNING: might reveal email addresses."
     trim_incoming_emails: "Trim part of the incoming emails that isn't relevant."
     private_email: "Don't include content from posts or topics in email title or email body. NOTE: also disables digest emails."
-    email_total_attachment_size_limit_kb: "Max total size of files attached to outgoing emails in kB. Set to 0 to disable sending of attachments."
+    email_total_attachment_size_limit_kb: "Max total size of files attached to outgoing emails. Set to 0 to disable sending of attachments."
     post_excerpts_in_emails: "In notification emails, always send excerpts instead of full posts"
     raw_email_max_length: "How many characters should be stored for incoming email."
     raw_rejected_email_max_length: "How many characters should be stored for rejected incoming email."
diff --git a/config/site_settings.yml b/config/site_settings.yml
index 1d19b5ab8fd..fd6a3746f1f 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -1396,6 +1396,7 @@ email:
   email_total_attachment_size_limit_kb:
     default: 0
     max: 51200
+    type: file_size_restriction
   post_excerpts_in_emails: false
   raw_email_max_length: 220000
   raw_rejected_email_max_length: 4000
@@ -1416,10 +1417,12 @@ files:
     client: true
     default: 4096
     max: 102400
+    type: file_size_restriction
   max_attachment_size_kb:
     client: true
     default: 4096
     max: 1024000
+    type: file_size_restriction
   max_image_megapixels:
     default: 40
     min: 5
@@ -1428,6 +1431,7 @@ files:
     hidden: true
     default: 50000
     max: 1024000
+    type: file_size_restriction
   theme_authorized_extensions:
     default: "wasm|jpg|jpeg|png|woff|woff2|svg|eot|ttf|otf|gif|webp|avif|js"
     type: list
@@ -1490,6 +1494,7 @@ files:
     default: 1024
     min: 1
     max: 10240
+    type: file_size_restriction
   secure_uploads_pm_only:
     default: false
     hidden: true
diff --git a/lib/site_settings/type_supervisor.rb b/lib/site_settings/type_supervisor.rb
index 938fda2bf30..151a0c0ec92 100644
--- a/lib/site_settings/type_supervisor.rb
+++ b/lib/site_settings/type_supervisor.rb
@@ -55,6 +55,7 @@ class SiteSettings::TypeSupervisor
         emoji_list: 24,
         html_deprecated: 25,
         tag_group_list: 26,
+        file_size_restriction: 27,
       )
   end
 
@@ -180,7 +181,7 @@ class SiteSettings::TypeSupervisor
       end
     end
 
-    if type == :integer
+    if type == :integer || type == :file_size_restriction
       result[:min] = @validators[name].dig(:opts, :min) if @validators[name].dig(
         :opts,
         :min,
@@ -304,6 +305,8 @@ class SiteSettings::TypeSupervisor
       GroupSettingValidator
     when self.class.types[:integer]
       IntegerSettingValidator
+    when self.class.types[:file_size_restriction]
+      IntegerSettingValidator
     when self.class.types[:regex]
       RegexSettingValidator
     when self.class.types[:string], self.class.types[:list], self.class.types[:enum]
diff --git a/spec/lib/shrink_uploaded_image_spec.rb b/spec/lib/shrink_uploaded_image_spec.rb
index 08a533cef85..58b5522a69d 100644
--- a/spec/lib/shrink_uploaded_image_spec.rb
+++ b/spec/lib/shrink_uploaded_image_spec.rb
@@ -86,7 +86,7 @@ RSpec.describe ShrinkUploadedImage do
     it "returns false when the upload is above the size limit" do
       post = Fabricate(:post, raw: "<img src='#{upload.url}'>")
       post.link_post_uploads
-      SiteSetting.max_image_size_kb = 0.001 # 1 byte
+      SiteSetting.max_image_size_kb = 0
 
       result =
         ShrinkUploadedImage.new(
diff --git a/spec/tasks/uploads_spec.rb b/spec/tasks/uploads_spec.rb
index f2470377deb..2b251b22ae6 100644
--- a/spec/tasks/uploads_spec.rb
+++ b/spec/tasks/uploads_spec.rb
@@ -240,7 +240,7 @@ RSpec.describe "tasks/uploads" do
 
     it "updates attributes of uploads that are over the size limit" do
       upload.update!(thumbnail_height: 0)
-      SiteSetting.max_image_size_kb = 0.001 # 1 byte
+      SiteSetting.max_image_size_kb = 1
 
       expect { invoke_task }.to change { upload.reload.thumbnail_height }.to(200)
     end