diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index f4ba0f2f29..5f19ce4671 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -120,6 +120,11 @@ module Homebrew
           [:switch, "--overwrite", {
             description: "Delete files that already exist in the prefix while linking.",
           }],
+          [:switch, "--ask", {
+            description: "Ask for confirmation before downloading and installing formulae. " \
+                         "Print bottles and dependencies download size and install size.",
+            env:         :ask,
+          }],
         ].each do |args|
           options = args.pop
           send(*args, **options)
@@ -302,6 +307,8 @@ module Homebrew
         Install.perform_preinstall_checks_once
         Install.check_cc_argv(args.cc)
 
+        Install.ask(formulae, args: args) if args.ask?
+
         Install.install_formulae(
           installed_formulae,
           build_bottle:               args.build_bottle?,
diff --git a/Library/Homebrew/cmd/reinstall.rb b/Library/Homebrew/cmd/reinstall.rb
index cadda01cbe..3c767f0619 100644
--- a/Library/Homebrew/cmd/reinstall.rb
+++ b/Library/Homebrew/cmd/reinstall.rb
@@ -63,6 +63,11 @@ module Homebrew
           [:switch, "-g", "--git", {
             description: "Create a Git repository, useful for creating patches to the software.",
           }],
+          [:switch, "--ask", {
+            description: "Ask for confirmation before downloading and upgrading formulae. " \
+                         "Print bottles and dependencies download size, install and net install size.",
+            env:         :ask,
+          }],
         ].each do |args|
           options = args.pop
           send(*args, **options)
@@ -126,6 +131,9 @@ module Homebrew
         unless formulae.empty?
           Install.perform_preinstall_checks_once
 
+          # If asking the user is enabled, show dependency and size information.
+          Install.ask(formulae, args: args) if args.ask?
+
           formulae.each do |formula|
             if formula.pinned?
               onoe "#{formula.full_name} is pinned. You must unpin it to reinstall."
diff --git a/Library/Homebrew/cmd/upgrade.rb b/Library/Homebrew/cmd/upgrade.rb
index 6ab70581ac..b48ace323d 100644
--- a/Library/Homebrew/cmd/upgrade.rb
+++ b/Library/Homebrew/cmd/upgrade.rb
@@ -71,6 +71,11 @@ module Homebrew
           [:switch, "--overwrite", {
             description: "Delete files that already exist in the prefix while linking.",
           }],
+          [:switch, "--ask", {
+            description: "Ask for confirmation before downloading and upgrading formulae. " \
+                         "Print bottles and dependencies download size, install and net install size.",
+            env:         :ask,
+          }],
         ].each do |args|
           options = args.pop
           send(*args, **options)
@@ -211,11 +216,14 @@ module Homebrew
               "#{f.full_specified_name} #{f.pkg_version}"
             end
           end
-          puts formulae_upgrades.join("\n")
+          puts formulae_upgrades.join("\n") unless args.ask?
         end
 
         Install.perform_preinstall_checks_once
 
+        # Main block: if asking the user is enabled, show dependency and size information.
+        Install.ask(formulae_to_install, args: args) if args.ask?
+
         Upgrade.upgrade_formulae(
           formulae_to_install,
           flags:                      args.flags_only,
diff --git a/Library/Homebrew/env_config.rb b/Library/Homebrew/env_config.rb
index d44acc84b8..213a0fdae8 100644
--- a/Library/Homebrew/env_config.rb
+++ b/Library/Homebrew/env_config.rb
@@ -48,6 +48,11 @@ module Homebrew
                      "trying any other/default URLs.",
         boolean:     true,
       },
+      HOMEBREW_ASK:                              {
+        description: "If set, pass `--ask`to all formulae `brew install`, `brew upgrade` and `brew reinstall` " \
+                     "commands.",
+        boolean:     true,
+      },
       HOMEBREW_AUTO_UPDATE_SECS:                 {
         description:  "Run `brew update` once every `$HOMEBREW_AUTO_UPDATE_SECS` seconds before some commands, " \
                       "e.g. `brew install`, `brew upgrade` and `brew tap`. Alternatively, " \
diff --git a/Library/Homebrew/extend/kernel.rb b/Library/Homebrew/extend/kernel.rb
index 94bcf520c0..7d21851fd0 100644
--- a/Library/Homebrew/extend/kernel.rb
+++ b/Library/Homebrew/extend/kernel.rb
@@ -459,13 +459,13 @@ module Kernel
   end
 
   def disk_usage_readable(size_in_bytes)
-    if size_in_bytes >= 1_073_741_824
+    if size_in_bytes.abs >= 1_073_741_824
       size = size_in_bytes.to_f / 1_073_741_824
       unit = "GB"
-    elsif size_in_bytes >= 1_048_576
+    elsif size_in_bytes.abs >= 1_048_576
       size = size_in_bytes.to_f / 1_048_576
       unit = "MB"
-    elsif size_in_bytes >= 1_024
+    elsif size_in_bytes.abs >= 1_024
       size = size_in_bytes.to_f / 1_024
       unit = "KB"
     else
diff --git a/Library/Homebrew/install.rb b/Library/Homebrew/install.rb
index 80c3c54069..1f14cbd211 100644
--- a/Library/Homebrew/install.rb
+++ b/Library/Homebrew/install.rb
@@ -327,6 +327,22 @@ module Homebrew
         puts formula_names.join(" ")
       end
 
+      # If asking the user is enabled, show dependency and size information.
+      def ask(formulae, args:)
+        ohai "Looking for bottles..."
+
+        sized_formulae = compute_sized_formulae(formulae, args: args)
+        sizes = compute_total_sizes(sized_formulae, debug: args.debug?)
+
+        puts "#{::Utils.pluralize("Formula", sized_formulae.count, plural: "e")} \
+(#{sized_formulae.count}): #{sized_formulae.join(", ")}\n\n"
+        puts "Download Size: #{disk_usage_readable(sizes[:download])}"
+        puts "Install Size:  #{disk_usage_readable(sizes[:installed])}"
+        puts "Net Install Size: #{disk_usage_readable(sizes[:net])}" if sizes[:net] != 0
+
+        ask_input
+      end
+
       private
 
       def perform_preinstall_checks(all_fatal: false)
@@ -363,6 +379,86 @@ module Homebrew
 
         Upgrade.install_formula(formula_installer, upgrade:)
       end
+
+      def ask_input
+        ohai "Do you want to proceed with the installation? [Y/y/yes/N/n]"
+        accepted_inputs = %w[y yes]
+        declined_inputs = %w[n no]
+        loop do
+          result = $stdin.gets
+          return unless result
+
+          result = result.chomp.strip.downcase
+          if accepted_inputs.include?(result)
+            break
+          elsif declined_inputs.include?(result)
+            exit 1
+          else
+            puts "Invalid input. Please enter 'Y', 'y', or 'yes' to proceed, or 'N' to abort."
+          end
+        end
+      end
+
+      # Build a unique list of formulae to size by including:
+      # 1. The original formulae to install.
+      # 2. Their outdated dependents (subject to pruning criteria).
+      # 3. Optionally, any installed formula that depends on one of these and is outdated.
+      def compute_sized_formulae(formulae, args:)
+        sized_formulae = formulae.flat_map do |formula|
+          # Always include the formula itself.
+          formula_list = [formula]
+
+          deps = args.build_from_source? ? formula.deps.build : formula.deps.required
+
+          outdated_dependents = deps.map(&:to_formula).reject(&:pinned?).select do |dep|
+            dep.installed_kegs.empty? || (dep.bottled? && dep.outdated?)
+          end
+          deps.map(&:to_formula).each do |f|
+            outdated_dependents.concat(f.recursive_dependencies.map(&:to_formula).reject(&:pinned?).select do |dep|
+              dep.installed_kegs.empty? || (dep.bottled? && dep.outdated?)
+            end)
+          end
+          formula_list.concat(outdated_dependents)
+
+          formula_list
+        end
+
+        # Add any installed formula that depends on one of the sized formulae and is outdated.
+        unless Homebrew::EnvConfig.no_installed_dependents_check?
+          sized_formulae.concat(Formula.installed.select do |installed_formula|
+            installed_formula.bottled? && installed_formula.outdated? &&
+              installed_formula.deps.required.map(&:to_formula).intersect?(sized_formulae)
+          end)
+        end
+
+        sized_formulae.uniq(&:to_s).compact
+      end
+
+      # Compute the total sizes (download, installed, and net) for the given formulae.
+      def compute_total_sizes(sized_formulae, debug: false)
+        total_download_size  = 0
+        total_installed_size = 0
+        total_net_size       = 0
+
+        sized_formulae.select(&:bottle).each do |formula|
+          bottle = formula.bottle
+          # Fetch additional bottle metadata (if necessary).
+          bottle.fetch_tab(quiet: !debug)
+
+          total_download_size  += bottle.bottle_size.to_i if bottle.bottle_size
+          total_installed_size += bottle.installed_size.to_i if bottle.installed_size
+
+          # Sum disk usage for all installed kegs of the formula.
+          next if formula.installed_kegs.none?
+
+          kegs_dep_size = formula.installed_kegs.sum { |keg| keg.disk_usage.to_i }
+          total_net_size += bottle.installed_size.to_i - kegs_dep_size if bottle.installed_size
+        end
+
+        { download:  total_download_size,
+          installed: total_installed_size,
+          net:       total_net_size }
+      end
     end
   end
 end
diff --git a/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/install_cmd.rbi b/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/install_cmd.rbi
index 2bd0d91e02..164120bae8 100644
--- a/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/install_cmd.rbi
+++ b/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/install_cmd.rbi
@@ -20,6 +20,9 @@ class Homebrew::Cmd::InstallCmd::Args < Homebrew::CLI::Args
   sig { returns(T.nilable(String)) }
   def appdir; end
 
+  sig { returns(T::Boolean) }
+  def ask?; end
+
   sig { returns(T.nilable(String)) }
   def audio_unit_plugindir; end
 
diff --git a/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/reinstall.rbi b/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/reinstall.rbi
index 10f9c8fb8f..beee25bbbe 100644
--- a/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/reinstall.rbi
+++ b/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/reinstall.rbi
@@ -17,6 +17,9 @@ class Homebrew::Cmd::Reinstall::Args < Homebrew::CLI::Args
   sig { returns(T.nilable(String)) }
   def appdir; end
 
+  sig { returns(T::Boolean) }
+  def ask?; end
+
   sig { returns(T.nilable(String)) }
   def audio_unit_plugindir; end
 
diff --git a/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/upgrade_cmd.rbi b/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/upgrade_cmd.rbi
index bc2ba6224b..3eb336f954 100644
--- a/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/upgrade_cmd.rbi
+++ b/Library/Homebrew/sorbet/rbi/dsl/homebrew/cmd/upgrade_cmd.rbi
@@ -14,6 +14,9 @@ class Homebrew::Cmd::UpgradeCmd::Args < Homebrew::CLI::Args
   sig { returns(T.nilable(String)) }
   def appdir; end
 
+  sig { returns(T::Boolean) }
+  def ask?; end
+
   sig { returns(T.nilable(String)) }
   def audio_unit_plugindir; end
 
diff --git a/Library/Homebrew/sorbet/rbi/dsl/homebrew/env_config.rbi b/Library/Homebrew/sorbet/rbi/dsl/homebrew/env_config.rbi
index 2e4bfabb92..80238758ce 100644
--- a/Library/Homebrew/sorbet/rbi/dsl/homebrew/env_config.rbi
+++ b/Library/Homebrew/sorbet/rbi/dsl/homebrew/env_config.rbi
@@ -28,6 +28,9 @@ module Homebrew::EnvConfig
     sig { returns(T::Boolean) }
     def artifact_domain_no_fallback?; end
 
+    sig { returns(T::Boolean) }
+    def ask?; end
+
     sig { returns(T.nilable(::String)) }
     def auto_update_secs; end
 
diff --git a/Library/Homebrew/test/cmd/install_spec.rb b/Library/Homebrew/test/cmd/install_spec.rb
index 4772947bf0..ef74f06cc3 100644
--- a/Library/Homebrew/test/cmd/install_spec.rb
+++ b/Library/Homebrew/test/cmd/install_spec.rb
@@ -4,6 +4,7 @@ require "cmd/install"
 require "cmd/shared_examples/args_parse"
 
 RSpec.describe Homebrew::Cmd::InstallCmd do
+  include FileUtils
   it_behaves_like "parseable arguments"
 
   it "installs formulae", :integration_test do
@@ -84,4 +85,44 @@ RSpec.describe Homebrew::Cmd::InstallCmd do
     expect(HOMEBREW_CELLAR/"testball1/0.1/bin/test.dSYM/Contents/Resources/DWARF/test").to be_a_file if OS.mac?
     expect(HOMEBREW_CACHE/"Sources/testball1").to be_a_directory
   end
+
+  it "installs with asking for user prompts without installed dependent checks", :integration_test do
+    setup_test_formula "testball1"
+
+    expect do
+      brew "install", "--ask", "testball1"
+    end.to output(/.*Formula\s*\(1\):\s*testball1.*/).to_stdout.and not_to_output.to_stderr
+
+    expect(HOMEBREW_CELLAR/"testball1/0.1/bin/test").to be_a_file
+  end
+
+  it "installs with asking for user prompts with installed dependent checks", :integration_test do
+    setup_test_formula "testball1", <<~RUBY
+      depends_on "testball5"
+      # should work as its not building but test doesnt pass if dependant
+      # depends_on "build" => :build
+      depends_on "installed"
+    RUBY
+    setup_test_formula "installed"
+    setup_test_formula "testball5", <<~RUBY
+      depends_on "testball4"
+    RUBY
+    setup_test_formula "testball4", ""
+    setup_test_formula "hiop"
+    setup_test_formula "build"
+
+    # Mock `Formula#any_version_installed?` by creating the tab in a plausible keg directory
+    keg_dir = HOMEBREW_CELLAR/"installed"/"1.0"
+    keg_dir.mkpath
+    touch keg_dir/AbstractTab::FILENAME
+
+    expect do
+      brew "install", "--ask", "testball1"
+    end.to output(/.*Formulae\s*\(3\):\s*testball1\s*,?\s*testball5\s*,?\s*testball4.*/).to_stdout
+                                                                                        .and not_to_output.to_stderr
+
+    expect(HOMEBREW_CELLAR/"testball1/0.1/bin/test").to be_a_file
+    expect(HOMEBREW_CELLAR/"testball4/0.1/bin/testball4").to be_a_file
+    expect(HOMEBREW_CELLAR/"testball5/0.1/bin/testball5").to be_a_file
+  end
 end
diff --git a/Library/Homebrew/test/cmd/reinstall_spec.rb b/Library/Homebrew/test/cmd/reinstall_spec.rb
index fd5690de26..77e55c994c 100644
--- a/Library/Homebrew/test/cmd/reinstall_spec.rb
+++ b/Library/Homebrew/test/cmd/reinstall_spec.rb
@@ -20,4 +20,18 @@ RSpec.describe Homebrew::Cmd::Reinstall do
 
     expect(foo_dir).to exist
   end
+
+  it "reinstalls a Formula with ask input", :integration_test do
+    install_test_formula "testball"
+    foo_dir = HOMEBREW_CELLAR/"testball/0.1/bin"
+    expect(foo_dir).to exist
+    FileUtils.rm_r(foo_dir)
+
+    expect { brew "reinstall", "--ask", "testball" }
+      .to output(/.*Formula\s*\(1\):\s*testball.*/).to_stdout
+                                                   .and not_to_output.to_stderr
+                                                                     .and be_a_success
+
+    expect(foo_dir).to exist
+  end
 end
diff --git a/Library/Homebrew/test/cmd/upgrade_spec.rb b/Library/Homebrew/test/cmd/upgrade_spec.rb
index 4e7953ee74..27b9fc7891 100644
--- a/Library/Homebrew/test/cmd/upgrade_spec.rb
+++ b/Library/Homebrew/test/cmd/upgrade_spec.rb
@@ -4,6 +4,7 @@ require "cmd/shared_examples/args_parse"
 require "cmd/upgrade"
 
 RSpec.describe Homebrew::Cmd::UpgradeCmd do
+  include FileUtils
   it_behaves_like "parseable arguments"
 
   it "upgrades a Formula and cleans up old versions", :integration_test do
@@ -15,4 +16,68 @@ RSpec.describe Homebrew::Cmd::UpgradeCmd do
     expect(HOMEBREW_CELLAR/"testball/0.1").to be_a_directory
     expect(HOMEBREW_CELLAR/"testball/0.0.1").not_to exist
   end
+
+  it "upgrades with asking for user prompts", :integration_test do
+    setup_test_formula "testball"
+    (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath
+
+    expect do
+      brew "upgrade", "--ask"
+    end.to output(/.*Formula\s*\(1\):\s*testball.*/).to_stdout.and not_to_output.to_stderr
+
+    expect(HOMEBREW_CELLAR/"testball/0.1").to be_a_directory
+    expect(HOMEBREW_CELLAR/"testball/0.0.1").not_to exist
+  end
+
+  it "upgrades with asking for user prompts with dependants checks", :integration_test do
+    setup_test_formula "testball", <<~RUBY
+      depends_on "testball5"
+      # should work as its not building but test doesnt pass if dependant
+      # depends_on "build" => :build
+      depends_on "installed"
+    RUBY
+    setup_test_formula "installed"
+    setup_test_formula "testball5", <<~RUBY
+      depends_on "testball4"
+    RUBY
+    setup_test_formula "testball4"
+    setup_test_formula "hiop"
+    setup_test_formula "build"
+
+    (HOMEBREW_CELLAR/"testball/0.0.1/foo").mkpath
+    (HOMEBREW_CELLAR/"testball5/0.0.1/foo").mkpath
+    (HOMEBREW_CELLAR/"testball4/0.0.1/foo").mkpath
+
+    keg_dir = HOMEBREW_CELLAR/"installed"/"1.0"
+    keg_dir.mkpath
+    touch keg_dir/AbstractTab::FILENAME
+
+    regex = /
+      Formulae\s*\(3\):\s*
+      (
+        testball|testball5|testball4
+      )
+      \s*,\s*
+      (?!\1)
+      (
+        testball|testball5|testball4
+      )
+      \s*,\s*
+      (?!\1|\2)
+      (
+        testball|testball5|testball4
+      )
+    /x
+    expect do
+      brew "upgrade", "--ask"
+    end.to output(regex)
+      .to_stdout.and not_to_output.to_stderr
+
+    expect(HOMEBREW_CELLAR/"testball/0.1").to be_a_directory
+    expect(HOMEBREW_CELLAR/"testball/0.0.1").not_to exist
+    expect(HOMEBREW_CELLAR/"testball5/0.1").to be_a_directory
+    expect(HOMEBREW_CELLAR/"testball5/0.0.1").not_to exist
+    expect(HOMEBREW_CELLAR/"testball4/0.1").to be_a_directory
+    expect(HOMEBREW_CELLAR/"testball4/0.0.1").not_to exist
+  end
 end
diff --git a/Library/Homebrew/test/support/fixtures/tarballs/testball4-0.1-linux.tbz b/Library/Homebrew/test/support/fixtures/tarballs/testball4-0.1-linux.tbz
new file mode 100644
index 0000000000..72957a4c13
Binary files /dev/null and b/Library/Homebrew/test/support/fixtures/tarballs/testball4-0.1-linux.tbz differ
diff --git a/Library/Homebrew/test/support/fixtures/tarballs/testball4-0.1.tbz b/Library/Homebrew/test/support/fixtures/tarballs/testball4-0.1.tbz
new file mode 100644
index 0000000000..c7c57aee5f
Binary files /dev/null and b/Library/Homebrew/test/support/fixtures/tarballs/testball4-0.1.tbz differ
diff --git a/Library/Homebrew/test/support/fixtures/tarballs/testball5-0.1-linux.tbz b/Library/Homebrew/test/support/fixtures/tarballs/testball5-0.1-linux.tbz
new file mode 100644
index 0000000000..4d35e20d2b
Binary files /dev/null and b/Library/Homebrew/test/support/fixtures/tarballs/testball5-0.1-linux.tbz differ
diff --git a/Library/Homebrew/test/support/fixtures/tarballs/testball5-0.1.tbz b/Library/Homebrew/test/support/fixtures/tarballs/testball5-0.1.tbz
new file mode 100644
index 0000000000..06def51fbd
Binary files /dev/null and b/Library/Homebrew/test/support/fixtures/tarballs/testball5-0.1.tbz differ
diff --git a/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb b/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
index 8c5c1740d2..f8f3b0f60a 100644
--- a/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
+++ b/Library/Homebrew/test/support/helper/spec/shared_context/integration_test.rb
@@ -134,13 +134,21 @@ RSpec.shared_context "integration test" do # rubocop:disable RSpec/ContextWordin
                          bottle_block: nil, tab_attributes: nil)
     case name
     when /^testball/
-      # Use a different tarball for testball2 to avoid lock errors when writing concurrency tests
-      prefix = (name == "testball2") ? "testball2" : "testball"
-      tarball = if OS.linux?
-        TEST_FIXTURE_DIR/"tarballs/#{prefix}-0.1-linux.tbz"
+      case name
+      when "testball4", "testball5"
+        prefix = name
+        program_name = name
+      when "testball2"
+        prefix = name
+        program_name = "test"
       else
-        TEST_FIXTURE_DIR/"tarballs/#{prefix}-0.1.tbz"
+        prefix = "testball"
+        program_name = "test"
       end
+
+      tarball_name = "#{prefix}-0.1#{"-linux" if OS.linux?}.tbz"
+      tarball = TEST_FIXTURE_DIR / "tarballs/#{tarball_name}"
+
       content = <<~RUBY
         desc "Some test"
         homepage "https://brew.sh/#{name}"
@@ -150,12 +158,12 @@ RSpec.shared_context "integration test" do # rubocop:disable RSpec/ContextWordin
         option "with-foo", "Build with foo"
         #{bottle_block}
         def install
-          (prefix/"foo"/"test").write("test") if build.with? "foo"
+          (prefix/"foo"/"#{program_name}").write("#{program_name}") if build.with? "foo"
           prefix.install Dir["*"]
-          (buildpath/"test.c").write \
-            "#include <stdio.h>\\nint main(){printf(\\"test\\");return 0;}"
+          (buildpath/"#{program_name}.c").write \
+            "#include <stdio.h>\\nint main(){printf(\\"#{program_name}\\");return 0;}"
           bin.mkpath
-          system ENV.cc, "test.c", "-o", bin/"test"
+          system ENV.cc, "#{program_name}.c", "-o", bin/"#{program_name}"
         end
 
         #{content}