diff --git a/Library/Homebrew/dev-cmd/contributions.rb b/Library/Homebrew/dev-cmd/contributions.rb
index 639807ce88..993f22bfd4 100755
--- a/Library/Homebrew/dev-cmd/contributions.rb
+++ b/Library/Homebrew/dev-cmd/contributions.rb
@@ -19,11 +19,11 @@ module Homebrew
   sig { returns(CLI::Parser) }
   def contributions_args
     Homebrew::CLI::Parser.new do
-      usage_banner "`contributions` <email|name> [<--repositories>`=`] [<--csv>]"
+      usage_banner "`contributions` <email|username> [<--repositories>`=`] [<--csv>]"
       description <<~EOS
         Contributions to Homebrew repos for a user.
 
-        The first argument is a name (e.g. "BrewTestBot") or an email address (e.g. "brewtestbot@brew.sh").
+        The first argument is a GitHub username (e.g. "BrewTestBot") or an email address (e.g. "brewtestbot@brew.sh").
       EOS
 
       comma_array "--repositories",
@@ -65,13 +65,20 @@ module Homebrew
       end
 
       repo_path = find_repo_path_for_repo(repo)
+      tap = Tap.fetch("homebrew", repo)
       unless repo_path.exist?
         opoo "Repository #{repo} not yet tapped! Tapping it now..."
-        Tap.fetch("homebrew", repo).install
+        tap.install
+      end
+
+      repo_full_name = if repo == "brew"
+        "homebrew/brew"
+      else
+        tap.full_name
       end
 
       results[repo] = {
-        commits:       git_log_author_cmd(T.must(repo_path), args),
+        commits:       GitHub.repo_commit_count_for_user(repo_full_name, args.named.first),
         coauthorships: git_log_trailers_cmd(T.must(repo_path), "Co-authored-by", args),
         signoffs:      git_log_trailers_cmd(T.must(repo_path), "Signed-off-by", args),
       }
@@ -127,15 +134,6 @@ module Homebrew
       .sum(&:sum) # 956
   end
 
-  sig { params(repo_path: Pathname, args: Homebrew::CLI::Args).returns(Integer) }
-  def git_log_author_cmd(repo_path, args)
-    cmd = ["git", "-C", repo_path, "log", "--oneline", "--author=#{args.named.first}"]
-    cmd << "--before=#{args.to}" if args.to
-    cmd << "--after=#{args.from}" if args.from
-
-    Utils.safe_popen_read(*cmd).lines.count
-  end
-
   sig { params(repo_path: Pathname, trailer: String, args: Homebrew::CLI::Args).returns(Integer) }
   def git_log_trailers_cmd(repo_path, trailer, args)
     cmd = ["git", "-C", repo_path, "log", "--oneline"]
diff --git a/Library/Homebrew/utils/github.rb b/Library/Homebrew/utils/github.rb
index 7222a0b641..e4fc791c4c 100644
--- a/Library/Homebrew/utils/github.rb
+++ b/Library/Homebrew/utils/github.rb
@@ -699,4 +699,14 @@ module GitHub
 
     output[/^Status: (200)/, 1] != "200"
   end
+
+  def repo_commit_count_for_user(nwo, user)
+    return if Homebrew::EnvConfig.no_github_api?
+
+    commits = 0
+    API.paginate_rest("#{API_URL}/repos/#{nwo}/commits", additional_query_params: "author=#{user}") do |result|
+      commits += result.length
+    end
+    commits
+  end
 end
diff --git a/Library/Homebrew/utils/github/api.rb b/Library/Homebrew/utils/github/api.rb
index 610b8ba0a8..2dd8bfe408 100644
--- a/Library/Homebrew/utils/github/api.rb
+++ b/Library/Homebrew/utils/github/api.rb
@@ -253,9 +253,9 @@ module GitHub
       end
     end
 
-    def paginate_rest(url, per_page: 100)
+    def paginate_rest(url, additional_query_params: nil, per_page: 100)
       (1..API_MAX_PAGES).each do |page|
-        result = API.open_rest("#{url}?per_page=#{per_page}&page=#{page}")
+        result = API.open_rest("#{url}?per_page=#{per_page}&page=#{page}&#{additional_query_params}")
         yield(result, page)
       end
     end