This repository has been archived by the owner. It is now read-only.
Stopwatch functionality for Go
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.

Archived project. No maintenance.

This project is not maintained anymore and is archived. Feel free to fork and make your own changes if needed. For more detail read my blog post: Taking an indefinite sabbatical from my projects

Thanks to everyone for their valuable feedback and contributions.

Stopwatch GoDoc Build Status

Stopwatch implements a simple stopwatch functionality. Features :

  • Two possible ways to create a Stopwatch. Initialized or uninitialized.
  • Start/Stop at any time or Reset.
  • Take an individual Lap time
  • Stores the list of each Lap
  • Satisfies JSON Marshaler/Unmarshaler interface
  • Handy methods like Print()/Log() to log a function execution time with one step.

Feel free to fork and send a pull request for any changes/improvements. For usage see examples below or click on the godoc badge.


go get



// create a new stopwatch, the timer starts immediately.
s := stopwatch.Start(0)

// get elapsed duration at any time
duration := s.ElapsedTime()
// some work ... another elapsed time
duration2 := s.ElapsedTime()

// create a new stopwatch, but do not start immediately
s := stopwatch.New()
// ... start it later

// start a stopwatch after a certain time
s := stopwatch.Start(2 * time.Second)
d1 := s.ElapsedTime() // d1 is zero here
// after two seconds it works
d2 := s.ElapsedTime()


// reset the stopwatch
// .. or stop the stopwatch

// resume the timer after a reset/stop


// create a lap
lap1 := s.Lap()
lap2 := s.Lap()
lap3 := s.Lap()

// get a list of all lap durations
list := s.Laps()

// lap returns zero duration if the timer is stopped/reseted
lap4 := s.Lap() // lap4 == time.Duration(0)


// String representation of stopwatch
fmt.Printf("stopwatch: %s", s)

// find out how long a function lasts
// outputs when the function returns:  myFunction - elapsed: 2.000629842s
defer Start(0).Print("myfunction")

// Marshal to a JSON object.
type API struct {
    Name      string     `json:"name"`
    Stopwatch *Stopwatch `json:"elapsed"`

a := API{
    Name:      "Example API Call",
    Stopwatch: Start(0),

// do some work ...
time.Sleep(time.Millisecond * 20)

b, err := json.Marshal(a)
if err != nil {
    t.Errorf("error: %s\n", err)

// output: {"name":"Example API Call","elapsed":"21.351657ms"}

// Unmarshal from a JSON object.
v := new(API)
err = json.Unmarshal(b, v)
if err != nil {
    t.Errorf("error: %s\n", err)

// Get back our elapsed time
duration := v.Stopwatch.ElapsedTime()



The MIT License (MIT) - see for more details