[SOLVED] Converting millis to Sec, Min, Hrs, Days

I am well aware of the built in time functions of processing, the ones that get you the computer clock time.

However I have a situation where I get large amounts of milliseconds of timed processes , and I would like to convert those in a human reading format.
Java has some library like:

long minutes = TimeUnit.MILLISECONDS.toMinutes(millis);

But that does not work for us.
I wonder if someone wrote at least a function to take care of this.
Thanks a lot,

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as you not say like " i want show ( nicely ) the time since start of the program"
you possibly now aware that that is what millis mean?

and yes, i also not aware of a ready “data time” tool for this
but try

int milli;
int hours;
int minutes; 
int seconds; 
int days;

void setup () {
  size(600, 400);

void draw() {
  text("millis from start = " + nf(days, 3) + "_"+ nf(hours, 2) + ":" + nf(minutes, 2) + ":" + nf(seconds, 2) + ":" + nf(milli, 3), 10, 20);

  text("Time: "+year()+"/"+nf(month(),2)+"/"+nf(day(),2)+"_"+nf(hour(),2)+":"+nf(minute(),2)+":"+nf(second(),2), width-170, 20);


void get_time() {
  milli = millis();
  seconds = milli / 1000;
  minutes = seconds / 60;
  hours = minutes / 60;
  days = hours / 24;

  //This text shows every number of millis, seconds, and minutes as if their independant numbers that don't reset to 0. 
  //aka don't loop around every particular number.  millis should go to 999 then to 0, and repeat.  
  //Seconds should be based on every 1000 millis, and zero back to 0 at 60000.  same for minutes.  

  //My theory is to create multiple functions which return a "looping" of each variable from 0 to it's own respective highest num.

  // point is you must calc all backward now:
  hours   = hours   - days * 24;
  minutes = minutes - days * 24 * 60             - hours * 60;
  seconds = seconds - days * 24 * 60 * 60        - hours * 60 * 60        - minutes * 60;
  milli   = milli   - days * 24 * 60 * 60 * 1000 - hours * 60 * 60 * 1000 - minutes * 60 * 1000 - seconds * 1000;

Thanks ,

I really meant “Converting Miliseconds in Sec, etc”

Here is what i came up with, it seems to work.

void MsConversion(int MS)

int totalSec= (MS / 1000);
int seconds = (MS / 1000) % 60;
int minutes = (MS / (1000*60)) % 60;
int hours = ((MS/(1000*60*60)) % 24);                      

String HumanTime= (hours+": " +minutes+ ": "+ seconds);
println (HumanTime);

Hope it helps other folks.



now that is confusing, where you get “Miliseconds” from if not from millis()??
and you say that in your question header!

void setup() {
  size(600, 1000);

void draw() {
  background (0);
  text(MsConversion(millis()) + "\n"+millis(), 44, 44);

String MsConversion(int MS) {
  int totalSec= (MS / 1000);
  int seconds = (MS / 1000) % 60;
  int minutes = (MS / (1000*60)) % 60;
  int hours = ((MS/(1000*60*60)) % 24);                      

  return hours+": " +minutes+ ": "+ seconds;
1 Like

I’m not sure why that didn’t work for you. I looked up the top TimeUnit example on stackoverflow based on your example code:

…and when I imported TimeUnit into a simple sketch, the code from the top answer worked just fine.

import java.util.concurrent.TimeUnit;

void draw() {
  int now = millis();
  String time = String.format("%d hrs, %d min, %d sec", 
    TimeUnit.MILLISECONDS.toSeconds(now) - 

16 hrs, 963 min, 6 sec

Of course, you have to do the same subtraction math (look at mins) that you do in a native Processing sketch for each step, based on which is the highest time unit and which is a remainder. To me this means that your native solution msConversion is more readable for a beginner than using TimeUnit.


Thanks a lot,
Did you have to install the “TimeUnit” library? Manually?

While on this subject:
How many days of millis do I get before Processing re-sets it to 0?

I have a long running application. I wonder if there’s a way to reset millis without making the user re-start the sketch?

My other option is to write my algorithms based on the computer date - time.
That seems really hard. During the same day, I could deduct an end time from a starting time.
such as (ending)23:33:55 minus (Starting) 18:55:33 . I would convert everything to seconds and get a difference.
But what do I do for timing a process that starts on one date and ends the next day?


No, just add the import command line to you sketch.

It is part of java (java.util.concurrent) and thus already available to import with no additional install needed.


import java.util.concurrent.TimeUnit;

// Max millis() in days:
println(TimeUnit.MILLISECONDS.toDays(MAX_INT)); // 24

// Max frameCount in days (60 FPS):
println(TimeUnit.SECONDS.toDays(MAX_INT/60)); // 414



So, if you plug that into now, that many milliseconds is about:

596 hrs

~24 days

Here are the details on frameCount overflow (not millis) and restarting:

Here is an example of creating your own resettable millis (the core millis cannot be reset).

As an alternative, you could keep your own higher resolution millis timer (e.g. a double) and increment it whenever millis overflows, every 24 days or so. Or when framecount overflows, if you plan to run for 2.3 years.

1 Like

You can also use System.currentTimeMillis() if need more than 24 days nonstop running: :alarm_clock:

That is cool, I never knew about CTM=System.currentTimeMillis();

It is a huge number, so I declared it in setup and then I made the difference in the loop,

It became a similar number with the millis.
public static long CTM;
long CTM_Ms;


CTM_Ms =System.currentTimeMillis()-CTM;
println (CTM_Ms);

Should I assume the “System.currentTimeMillis();” will run for ever?
Will never max out? For years to come?

Thanks, that got me out of trouble.

I read somewhere that millis reset in 9 days. True? That would mess up my data recordings.

It is a long, so just like we did with int:

System.out.println(new Date(Long.MAX_VALUE));

Sun Aug 17 03:12:55 GMT-04:00 292278994

So, only 292276975 years to go.

For discussion see:

Note that, realistically, if you plan on having a personal computer – or server – that executes a continuous process with no interruption for even 20 years: the chances are incredibly small that you will achiece that runtime, even with a good hardware and infrastructure plan. You will probably have a forced software update, soft reboot, hack, software failure, hardware failure, power failure, natural disaster, theft, et cetera. Odds are your hardware alone just won’t last ten years without a stop.

If you DID want a multi-decade continuous process, PDE probably isn’t a good way to do it. Most approaches (outside exceptional requirements like space probe engineering) don’t even try to do single-process, single-machine – they instead start by making a process distributed so that one can replace hardware and software incrementally over time to keep the process alive as things break and and become rapidly obsolete.

1 Like

Scroll up and take a look at my posted code sample: :scroll:

It’s 24 days and some hours for millis(). :flushed:

Or use frameCount for more than 1 year (414 days) uninterrupted: :calendar: