diff --git a/README.md b/README.md
index 07ac3f8..f8b6fef 100644
--- a/README.md
+++ b/README.md
@@ -105,6 +105,8 @@ Represents   | Style
       Grouping functions by [pkg, type]. (separate multiple by comma)
 -ignore string
       Ignore package paths with prefix. (separate multiple by comma)
+-nostd
+      Omit calls from/to std packages.
 -minlen uint
       Minimum edge length (for wider output). (default: 2)
 -nodesep float
@@ -125,12 +127,14 @@ Join [#go-callvis](https://gophers.slack.com/archives/go-callvis) channel at [go
 
 > *Not a member yet?* [Get invitation](https://gophersinvite.herokuapp.com).
 
-### How to contribute
+### How to help
 
 ###### Did you find any bugs or have some suggestions?
-
 Feel free to open [new issue](https://github.com/TrueFurby/go-callvis/issues/new) or start discussion in the slack channel.
 
+###### Do you want to contribute to the development?
+Fork the project and do a pull request. [Here](https://github.com/TrueFurby/go-callvis/projects/1) you can find the state of features.
+
 ### Known Issues
 
 ###### Each execution takes a lot of time, because currently:
diff --git a/main.go b/main.go
index e53a01e..4e674c9 100644
--- a/main.go
+++ b/main.go
@@ -24,6 +24,7 @@ var (
 	limitFlag   = flag.String("limit", "", "Limit package paths to prefix. (separate multiple by comma)")
 	groupFlag   = flag.String("group", "", "Grouping functions by [pkg, type] (separate multiple by comma).")
 	ignoreFlag  = flag.String("ignore", "", "Ignore package paths with prefix (separate multiple by comma).")
+	nostdFlag   = flag.Bool("nostd", false, "Omit calls to/from std packages.")
 	testFlag    = flag.Bool("tests", false, "Include test code.")
 	debugFlag   = flag.Bool("debug", false, "Enable verbose log.")
 	versionFlag = flag.Bool("version", false, "Show version and exit.")
@@ -73,13 +74,13 @@ func main() {
 		}
 	}
 
-	if err := run(&build.Default, *focusFlag, groupBy, limitPaths, ignorePaths, *testFlag, flag.Args()); err != nil {
+	if err := run(&build.Default, *focusFlag, groupBy, limitPaths, ignorePaths, *nostdFlag, *testFlag, flag.Args()); err != nil {
 		fmt.Fprintf(os.Stderr, "go-callvis: %s\n", err)
 		os.Exit(1)
 	}
 }
 
-func run(ctxt *build.Context, focus string, groupBy map[string]bool, limitPaths, ignorePaths []string, tests bool, args []string) error {
+func run(ctxt *build.Context, focus string, groupBy map[string]bool, limitPaths, ignorePaths []string, nostd, tests bool, args []string) error {
 	if len(args) == 0 {
 		return fmt.Errorf("missing arguments")
 	}
@@ -162,7 +163,7 @@ func run(ctxt *build.Context, focus string, groupBy map[string]bool, limitPaths,
 	logf("analysis took: %v", time.Since(t0))
 
 	return printOutput(mains[0].Pkg, result.CallGraph,
-		focusPkg, limitPaths, ignorePaths, groupBy)
+		focusPkg, limitPaths, ignorePaths, groupBy, nostd)
 }
 
 func logf(f string, a ...interface{}) {
diff --git a/output.go b/output.go
index 98e508d..e757b7c 100644
--- a/output.go
+++ b/output.go
@@ -14,7 +14,7 @@ import (
 
 var output io.Writer = os.Stdout
 
-func printOutput(mainPkg *types.Package, cg *callgraph.Graph, focusPkg *build.Package, limitPaths, ignorePaths []string, groupBy map[string]bool) error {
+func printOutput(mainPkg *types.Package, cg *callgraph.Graph, focusPkg *build.Package, limitPaths, ignorePaths []string, groupBy map[string]bool, nostd bool) error {
 	groupType := groupBy["type"]
 	groupPkg := groupBy["pkg"]
 
@@ -41,31 +41,37 @@ func printOutput(mainPkg *types.Package, cg *callgraph.Graph, focusPkg *build.Pa
 
 	logf("%d limit prefixes: %v", len(limitPaths), limitPaths)
 	logf("%d ignore prefixes: %v", len(ignorePaths), ignorePaths)
+	logf("no std packages: %v", nostd)
 
-	var inLimit = func(from, to *callgraph.Node) bool {
-		if len(limitPaths) == 0 {
-			return true
-		}
-		var fromOk, toOk bool
-		fromPath := from.Func.Pkg.Pkg.Path()
-		toPath := to.Func.Pkg.Pkg.Path()
+	var inLimit = func(node *callgraph.Node) bool {
+		pkgPath := node.Func.Pkg.Pkg.Path()
 		for _, p := range limitPaths {
-			if strings.HasPrefix(fromPath, p) {
-				fromOk = true
-			}
-			if strings.HasPrefix(toPath, p) {
-				toOk = true
+			if strings.HasPrefix(pkgPath, p) {
+				return true
 			}
-			if fromOk && toOk {
-				logf("in limit: %s -> %s", from, to)
+		}
+		return false
+	}
+
+	var isIgnored = func(node *callgraph.Node) bool {
+		pkgPath := node.Func.Pkg.Pkg.Path()
+		for _, p := range ignorePaths {
+			if strings.HasPrefix(pkgPath, p) {
 				return true
 			}
 		}
-		logf("NOT in limit: %s -> %s", from, to)
 		return false
 	}
 
+	var isStd = func(node *callgraph.Node) bool {
+		pkg, _ := build.Import(node.Func.Pkg.Pkg.Path(), "", 0)
+		return pkg.Goroot
+	}
+
+	count := 0
 	err := callgraph.GraphVisitEdges(cg, func(edge *callgraph.Edge) error {
+		count++
+
 		caller := edge.Caller
 		callee := edge.Callee
 
@@ -79,21 +85,26 @@ func printOutput(mainPkg *types.Package, cg *callgraph.Graph, focusPkg *build.Pa
 
 		// focus specific pkg
 		if focusPkg != nil &&
-			!(callerPkg.Path() == focusPkg.ImportPath || calleePkg.Path() == focusPkg.ImportPath) {
+			(callerPkg.Path() != focusPkg.ImportPath && calleePkg.Path() != focusPkg.ImportPath) {
 			return nil
 		}
 
 		// limit path prefixes
-		if !inLimit(caller, callee) {
+		if len(limitPaths) > 0 &&
+			(!inLimit(caller) || !inLimit(callee)) {
+			logf("NOT in limit: %s -> %s", caller, callee)
 			return nil
 		}
 
 		// ignore path prefixes
-		for _, p := range ignorePaths {
-			if strings.HasPrefix(callerPkg.Path(), p) ||
-				strings.HasPrefix(calleePkg.Path(), p) {
-				return nil
-			}
+		if len(ignorePaths) > 0 &&
+			(isIgnored(caller) || isIgnored(callee)) {
+			return nil
+		}
+
+		// omit std
+		if nostd && (isStd(caller) || isStd(callee)) {
+			return nil
 		}
 
 		var sprintNode = func(node *callgraph.Node) *dotNode {
@@ -261,7 +272,7 @@ func printOutput(mainPkg *types.Package, cg *callgraph.Graph, focusPkg *build.Pa
 		return err
 	}
 
-	logf("%d edges", len(edges))
+	logf("%d/%d edges", len(edges), count)
 
 	dot := &dotGraph{
 		Title:   mainPkg.Path(),