diff --git a/ui/build/config.go b/ui/build/config.go
index 1dd948c..077a4d1 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -35,10 +35,10 @@
 )
 
 const (
-	envConfigDir  = "vendor/google/tools/soong_config"
-	jsonSuffix    = "json"
+	envConfigDir = "vendor/google/tools/soong_config"
+	jsonSuffix   = "json"
 
-	configFetcher = "vendor/google/tools/soong/expconfigfetcher"
+	configFetcher         = "vendor/google/tools/soong/expconfigfetcher"
 	envConfigFetchTimeout = 10 * time.Second
 )
 
@@ -62,6 +62,7 @@
 	jsonModuleGraph bool
 	bp2build        bool
 	queryview       bool
+	reportMkMetrics bool // Collect and report mk2bp migration progress metrics.
 	soongDocs       bool
 	skipConfig      bool
 	skipKati        bool
@@ -155,7 +156,7 @@
 	}
 
 	configExists := false
-	outConfigFilePath := filepath.Join(config.OutDir(), envConfigName + jsonSuffix)
+	outConfigFilePath := filepath.Join(config.OutDir(), envConfigName+jsonSuffix)
 	if _, err := os.Stat(outConfigFilePath); err == nil {
 		configExists = true
 	}
@@ -711,6 +712,8 @@
 			c.skipConfig = true
 		} else if arg == "--skip-soong-tests" {
 			c.skipSoongTests = true
+		} else if arg == "--mk-metrics" {
+			c.reportMkMetrics = true
 		} else if len(arg) > 0 && arg[0] == '-' {
 			parseArgNum := func(def int) int {
 				if len(arg) > 2 {
@@ -1381,6 +1384,11 @@
 	return filepath.Join(c.LogsDir(), "bazel_metrics")
 }
 
+// MkFileMetrics returns the file path for make-related metrics.
+func (c *configImpl) MkMetrics() string {
+	return filepath.Join(c.LogsDir(), "mk_metrics.pb")
+}
+
 func (c *configImpl) SetEmptyNinjaFile(v bool) {
 	c.emptyNinjaFile = v
 }
diff --git a/ui/build/finder.go b/ui/build/finder.go
index 68efe21..262de3d 100644
--- a/ui/build/finder.go
+++ b/ui/build/finder.go
@@ -138,6 +138,17 @@
 		ctx.Fatalf("Could not export module list: %v", err)
 	}
 
+	// Gate collecting/reporting mk metrics on builds that specifically request
+	// it, as identifying the total number of mk files adds 4-5ms onto null
+	// builds.
+	if config.reportMkMetrics {
+		androidMksTotal := f.FindNamedAt(".", "Android.mk")
+
+		ctx.Metrics.SetToplevelMakefiles(len(androidMks))
+		ctx.Metrics.SetTotalMakefiles(len(androidMksTotal))
+		ctx.Metrics.DumpMkMetrics(config.MkMetrics())
+	}
+
 	// Stop searching a subdirectory recursively after finding a CleanSpec.mk.
 	cleanSpecs := f.FindFirstNamedAt(".", "CleanSpec.mk")
 	err = dumpListToFile(ctx, config, cleanSpecs, filepath.Join(dumpDir, "CleanSpec.mk.list"))