diff --git a/check.go b/check.go
index cdc22f5..1586436 100644
--- a/check.go
+++ b/check.go
@@ -94,8 +94,7 @@ func check(files []string) chan error {
 
 	results := []<-chan error{}
 
-	workers := 32
-	for w := 0; w < workers; w++ {
+	for w := 0; w < *ngo; w++ {
 		results = append(results, compute(jobs))
 	}
 
diff --git a/main.go b/main.go
index c261dd5..6bd0464 100644
--- a/main.go
+++ b/main.go
@@ -9,10 +9,12 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"runtime"
 )
 
 var algo = flag.String("a", "sha1", "algorithm to use")
 var mode = flag.Bool("c", false, "check")
+var ngo = flag.Int("n", runtime.NumCPU(), "number of goroutines")
 
 func main() {
 	flag.Parse()