diff --git a/mage/args_test.go b/mage/args_test.go
index 6997df8..d8ef8ab 100644
--- a/mage/args_test.go
+++ b/mage/args_test.go
@@ -12,12 +12,12 @@ func TestArgs(t *testing.T) {
 		Dir:    "./testdata/args",
 		Stderr: stderr,
 		Stdout: stdout,
-		Args:   []string{"status", "say", "hi", "bob", "count", "5", "status", "wait", "5ms", "cough", "false"},
+		Args:   []string{"status", "say", "hi", "bob", "count", "5", "status", "wait", "5ms", "cough", "false", "doubleIt", "3.1"},
 	}
 	code := Invoke(inv)
 	if code != 0 {
 		t.Log(stderr.String())
-		t.Fatalf("expected 1, but got %v", code)
+		t.Fatalf("expected 0, but got %v", code)
 	}
 	actual := stdout.String()
 	expected := `status
@@ -26,6 +26,7 @@ saying hi bob
 status
 waiting 5ms
 not coughing
+3.1 * 2 = 6.2
 `
 	if actual != expected {
 		t.Fatalf("output is not expected:\n%q", actual)
@@ -101,6 +102,29 @@ func TestBadDurationArg(t *testing.T) {
 	}
 }
 
+func TestBadFloat64Arg(t *testing.T) {
+	stderr := &bytes.Buffer{}
+	stdout := &bytes.Buffer{}
+	inv := Invocation{
+		Dir:    "./testdata/args",
+		Stderr: stderr,
+		Stdout: stdout,
+		Args:   []string{"doubleIt", "abc123"},
+	}
+	code := Invoke(inv)
+	if code != 2 {
+		t.Log("stderr:", stderr)
+		t.Log("stdout:", stdout)
+		t.Fatalf("expected code 2, but got %v", code)
+	}
+	actual := stderr.String()
+	expected := "can't convert argument \"abc123\" to float64\n"
+
+	if actual != expected {
+		t.Fatalf("output is not expected:\n%q", actual)
+	}
+}
+
 func TestMissingArgs(t *testing.T) {
 	stderr := &bytes.Buffer{}
 	stdout := &bytes.Buffer{}
diff --git a/mage/testdata/args/magefile.go b/mage/testdata/args/magefile.go
index de0f262..b74483c 100644
--- a/mage/testdata/args/magefile.go
+++ b/mage/testdata/args/magefile.go
@@ -50,3 +50,7 @@ func Cough(ctx context.Context, b bool) error {
 func HasDep() {
 	mg.Deps(mg.F(Say, "hi", "Susan"))
 }
+
+func DoubleIt(f float64) {
+	fmt.Printf("%.1f * 2 = %.1f\n", f, f*2)
+}
diff --git a/parse/parse.go b/parse/parse.go
index e68703b..c64e7cc 100644
--- a/parse/parse.go
+++ b/parse/parse.go
@@ -128,6 +128,14 @@ func (f Function) ExecCode() string {
 					os.Exit(2)
 				}
 				x++`, x)
+		case "float64":
+			parseargs += fmt.Sprintf(`
+				arg%d, err := strconv.ParseFloat(args.Args[x], 64)
+				if err != nil {
+					logger.Printf("can't convert argument %%q to float64\n", args.Args[x])
+					os.Exit(2)
+				}
+				x++`, x)
 		case "bool":
 			parseargs += fmt.Sprintf(`
 				arg%d, err := strconv.ParseBool(args.Args[x])
@@ -845,6 +853,7 @@ func toOneLine(s string) string {
 var argTypes = map[string]string{
 	"string":           "string",
 	"int":              "int",
+	"float64":          "float64",
 	"&{time Duration}": "time.Duration",
 	"bool":             "bool",
 }