Javascript: convert 24-hour time-of-day string to 12-hour time with AM/PM and no timezone

Question

The server is sending a string in this format: 18:00:00. This is a time-of-day value independent of any date. How to convert it to 6:00PM in Javascript? I could prepend today's date as a string to the value sent by the server and then parse the combined values and then try the .toTimeString() method of the Date object, but the format that time method emits is 24-hour time with a seconds chunk. I could write a function, but is there something built in?

Answer 1

function convertTo12HoursFormat(time24String){

let hours, minutes, period;

[hours,minutes] = time24String.split(':');

hours =parseInt(hours);
minutes = parseInt(minutes);
period = hours>=12 ? 'PM' : 'AM' ;
hours = hours %12 || 12;
minutes = minutes <10 ? '0' +minutes : minutes;



return `${hours}:${minutes} ${period}`;
}

// Example Usage:

convertTo12HoursFormat('23:45') // output: 11:45 PM

Answer 2

Rather than worry about manipulating the time string I'm letting date-fns do that part.

import { format } from 'date-fns';

function convertMilitaryToStandard(time) {
  return format(new Date(`1970-01-01T${time}`), 'hh:mm aa');
}

console.log(convertMilitaryToStandard('18:00:00')); // 06:00 PM

Answer 3

function convertTo12HourFormat(time24: string): string {
    const [hour, minute, second] = time24.split(':').map(Number);
    let period = 'AM';
    let hour12 = hour;

    if (hour >= 12) {
        period = 'PM';
        if (hour > 12) {
            hour12 = hour - 12;
        }
    }

    if (hour12 === 0) {
        hour12 = 12; // 0 hour in 12-hour format is 12 AM
    }

    return `${hour12.toString().padStart(2, '0')}:${minute.toString().padStart(2, '0')}:${second.toString().padStart(2, '0')} ${period}`;
}

const time24 = "17:00:00";
const time12 = convertTo12HourFormat(time24);
console.log(time12); // Output: 05:00:00 PM

Answer 4

// Function to convert a time from AM/PM format to military (24-hour) time format
function timeConversion(time) {
  // Split the input time string by colons to separate hours, minutes, and seconds
  const timeArray = time.split(':');
  
  // Parse the hour part as an integer (base 10)
  let hour = parseInt(timeArray[0], 10);
  
  // Extract the minute part as is
  const minute = timeArray[1];
  
  // Extract the first two characters of the seconds part
  const seconds = timeArray[2].slice(0, 2);
  
  // Extract the AM/PM part of the time
  const meridian = timeArray[2].slice(2);
  
  // Check if it's PM and not noon (12 PM) - add 12 hours to hour
  if (meridian === 'PM' && hour !== 12) {
    hour += 12;
  } else if (meridian === 'AM' && hour === 12) {
    // Check if it's AM and noon (12 AM) - set hour to 0
    hour = 0;
  }
  
  // Construct the military time string in the desired format
  const militaryTime = `${hour.toString().padStart(2, '0')}:${minute}:${seconds}`;
  
  // Return the military time string as the result
  return militaryTime;
}

// Example usage:
const amPmTime = '07:05:45PM';
const militaryTime = timeConversion(amPmTime);
console.log(militaryTime); // Output: '19:05:45'

Answer 5

I code-golfed it into a short and sweet arrow function

c=t=>([h,...r]=t.split(":"),(h=="12"?"12":h%12)+":"+r.join(":")+(h<12?" AM":" PM"))

Here's a version with a bit more readability as well as explicit variable definition.

const convertTime24_12=t=>{
    let [h,...rest]=t.split(":");
    return (h=="12"?"12":h%12)+":"+rest.join(":")+(h<12?" AM":" PM"));
}

Example usage

console.log(convertTime24_12("15:03:05"));
//"3:03:05 PM"

Answer 6

let hour = '12:01:00:pm'.split(':');
function getTime2(hr){
    hr[0] = +hr[0];//hr
    hr[1] = +hr[1]; //min
    hr[2] = +hr[2];//sec
    //hr[3] am/pm
    if(hr[1] < 10){
        hr[1] = `0${hr[1]}`;
    }
    if(hr[2] < 10){
        hr[2] = `0${hr[2]}`;
    }
    let time = '';
        //hr:min:sec:am/pm
    if(hr[0] === 12 && hr[3] === "am"){
        time += `00:${hr[1]}:${hr[2]}`
    }
    else if(hr[0] ===12 && hr[3] === "pm"){
        time += `${hr[0]}:${hr[1]}:${hr[2]}`
    }
    else if(hr[0] < 12 && hr[3] === "am"){
        time += `${hr[0]}:${hr[1]}:${hr[2]}`
    }
    else if(hr[0] < 12 && hr[3] === "pm"){
        time += `${12+hr[0]}:${hr[1]}:${hr[2]}`
    }
    return time;
}


console.log(getTime2(hour));

Answer 7

To get AM/PM, Check if the hour portion is less than 12, then it is AM, else PM.

To get the hour, do (hour % 12) || 12.

This should do it:

function formatTime(timeString) {
    const [hourString, minute] = timeString.split(":");
    const hour = +hourString % 24;
    return (hour % 12 || 12) + ":" + minute + (hour < 12 ? "AM" : "PM");
}

const tests = [
    "18:00:00",
    "6:00:00",
    "06:00:00",
    "12:00:00",
    "00:00:00",
    "24:00:00",
];
for (const s of tests) {
    console.log(formatTime(s));
}

Answer 8

toLocaleTimeString() makes this very simple. There is no need to do this yourself anymore. You'll be happier and live longer if you don't try to attack dates with string methods. (They will fight back.)

const timeString = '18:00:00'
// Prepend any date. Use your birthday.
const timeString12hr = new Date('1970-01-01T' + timeString + 'Z')
  .toLocaleTimeString('en-US',
    {timeZone:'UTC',hour12:true,hour:'numeric',minute:'numeric'}
  );
document.getElementById('myTime').innerText = timeString12hr

<h1 id='myTime'></h1>

Answer 9

if you need to get time without seconds at the output

const convertTime24to12 = (time24h) => {
  let time = time24h
    .toString()
    .match(/^([01]\d|2[0-3])(:)([0-5]\d)(:[0-5]\d)?$/) || [time24h];

  if (time.length > 1) {
    time = time.slice(1, -1);
    time[5] = +time[0] < 12 ? ' am' : ' pm';
    time[0] = +time[0] % 12 || 12;
  }
  return time.join(''); 
};

15:40:00

console.log(convertTime24to12("13:40:00"));

03:40

Answer 10

i'm using the Temporal Polyfill now: https://github.com/js-temporal/temporal-polyfill#readme

this is as simple as:

import { Temporal } from '@js-temporal/polyfill';
myDate = "2022-04-09T14:23:27.357Z"
Temporal.Instant.from(myDate).toLocaleString('en-US', { hour: 'numeric', minute: 'numeric' });
=> 5:23 PM // its also converting it to my browser's time zone

and if you change 'en-US' to 'de-DE' you'll get 24h instead

Answer 11

function timeConversion(s) {
  if (s.trim().endsWith("PM")) {
    return s
      .replace(/\d{2}/, (_) => {
        return Number(_) === 12 ? 12 : Number(_) + 12;
      })
      .replace("PM", "");
  } else {
    if (s.trim().startsWith("12")) {
      return s.replace("12", "00").replace("AM", "");
    } else {
      return s.replace("AM", "");
    }
  }
}

Answer 12

By Using Moment library we can convert 24 hour time format to 12 hour format.

moment('20:00', 'hh:mm').format('hh:mm')

//// output: 08:00

if you want to convert into AM and PM

moment('20:00', 'hh:mm a').format('hh:mm a')

//// output: 08:00 pm

Answer 13

It will be better to use momentjs

Just a little conversation "2 PM" to "14.00"

const number = moment("02:00 PM", ["h:mm A"]).format("HH:mm");
cosole.log(number); 

// "14.00" "14.00" to "2 PM"

const number = moment("14.00", ["HH.mm"]).format("hh:mm a");
cosole.log(number); // "02:00 pm"

Answer 14

function timeConversion(s) {
    let hour = parseInt(s.substring(0,2));
    hour = s.indexOf('AM') > - 1 && hour === 12 ? '00' : hour;
    hour = s.indexOf('PM') > - 1 && hour !== 12 ? hour + 12 : hour;
    hour = hour < 10 && hour > 0 ? '0'+hour : hour;

    return hour + s.substring(2,8);
}

Answer 15

function Time_Function() {
var date = new Date()
var time =""
var x= "AM"
if(date.getHours() >12){
    x= "PM"
}
time= date.getHours()%12 + x +":"+ date.getMinutes() +":"+ date.getSeconds()
}

Answer 16

Short ES6 code

const convertFrom24To12Format = (time24) => {
  const [sHours, minutes] = time24.match(/([0-9]{1,2}):([0-9]{2})/).slice(1);
  const period = +sHours < 12 ? 'AM' : 'PM';
  const hours = +sHours % 12 || 12;

  return `${hours}:${minutes} ${period}`;
}

const convertFrom12To24Format = (time12) => {
  const [sHours, minutes, period] = time12.match(/([0-9]{1,2}):([0-9]{2}) (AM|PM)/).slice(1);
  const PM = period === 'PM';
  const hours = (+sHours % 12) + (PM ? 12 : 0);

  return `${('0' + hours).slice(-2)}:${minutes}`;
}

Answer 17

Nothing built in, my solution would be as follows :

function tConvert (time) {
  // Check correct time format and split into components
  time = time.toString ().match (/^([01]\d|2[0-3])(:)([0-5]\d)(:[0-5]\d)?$/) || [time];

  if (time.length > 1) { // If time format correct
    time = time.slice (1);  // Remove full string match value
    time[5] = +time[0] < 12 ? 'AM' : 'PM'; // Set AM/PM
    time[0] = +time[0] % 12 || 12; // Adjust hours
  }
  return time.join (''); // return adjusted time or original string
}

tConvert ('18:00:00');

This function uses a regular expression to validate the time string and to split it into its component parts. Note also that the seconds in the time may optionally be omitted. If a valid time was presented, it is adjusted by adding the AM/PM indication and adjusting the hours.

The return value is the adjusted time if a valid time was presented or the original string.

Working example

(function() {

  function tConvert(time) {
    // Check correct time format and split into components
    time = time.toString().match(/^([01]\d|2[0-3])(:)([0-5]\d)(:[0-5]\d)?$/) || [time];

    if (time.length > 1) { // If time format correct
      time = time.slice(1); // Remove full string match value
      time[5] = +time[0] < 12 ? 'AM' : 'PM'; // Set AM/PM
      time[0] = +time[0] % 12 || 12; // Adjust hours
    }
    return time.join(''); // return adjusted time or original string
  }

  var tel = document.getElementById('tests');

  tel.innerHTML = tel.innerHTML.split(/\r*\n|\n\r*|\r/).map(function(v) {
    return v ? v + ' => "' + tConvert(v.trim()) + '"' : v;
  }).join('\n');
})();

<h3>tConvert tests : </h3>
<pre id="tests">
  18:00:00
  18:00
  00:00
  11:59:01
  12:00:00
  13:01:57
  24:00
  sdfsdf
  12:61:54
</pre>

Answer 18

A simple code for this will be

time = time.split(':');// here the time is like "16:14"
let meridiemTime = time[0] >= 12 && (time[0]-12 || 12) + ':' + time[1] + ' PM' || (Number(time[0]) || 12) + ':' + time[1] + ' AM';

You can adjust according to your time format

Answer 19

function timeformat(date1) {
  var date=new Date(date1);
  var month = date.toLocaleString('en-us', { month: 'long' });
  var mdate  =date.getDate();
  var year  =date.getFullYear();
  var hours = date.getHours();
  var minutes = date.getMinutes();
  var ampm = hours >= 12 ? 'pm' : 'am';
  hours = hours % 12;
  hours = hours ? hours : 12; // the hour '0' should be '12'
  minutes = minutes < 10 ? '0'+minutes : minutes;
  var strTime = mdate+"-"+month+"-"+year+" "+hours + ':' + minutes + ' ' + ampm;
  return strTime;
}
var ampm=timeformat("2019-01-11 12:26:43");
console.log(ampm);

Here the Function to Convert time into am or pm with Date,it may be help Someone.

Answer 20

Thanks to @HBP for paving the way here!

I found this to add a little flexibility to the solution.

The RegEx has been updated to accommodate times before noon.

This solution allows you to pass any string to it. As long as a valid time (in this format 18:00 || 18:00:00 || 3:00 || 3:00:00) is somewhere in that string, you're good to go.

Note: you can use just the militaryToTweleveHourConverter or take the guts out of the parseTime variable. However, I'm formatting a date from a database with date-fns then passing that formatted date to the converter.

Totally works. Hope this helps.

import dateFns from 'date-fns';



//* +---------------------------+
//* Format ex. Sat 1/1/18 1:00pm
//* +---------------------------+
const formatMonthDayYearTime = date =>
  militaryToTweleveHourConverter(
    dateFns.format(new Date(date), 'ddd M/DD/YY H:mm')
  );

//* +-------------------------------+
//* Convert MILITARY TIME to 12 hour
//* +-------------------------------+
const militaryToTweleveHourConverter = time => {
  const getTime = time.split(' ');

  const parseTime = getTime.map(res => {
    // Check for correct time format and split into components or return non-time units unaltered
    let timeUnit = res
      .toString()
      .match(/^([\d]|[0-1]\d|2[0-3])(:)([0-5]\d)(:[0-5]\d)?$/) || [res];

    console.log('timeUnit', timeUnit);
    // If the time format is matched, it will break the components into an array
    // ie. ["19:00", "19", ":", "00", undefined]
    if (timeUnit.length > 1) {
      // Remove full string match value
      timeUnit = timeUnit.slice(1);
      // Set am/pm and assign it to the last index in the array
      timeUnit[5] = timeUnit[0] < 12 ? 'am' : 'pm';
      // Adjust hours by subtracting 12 from anything greater than 12 and replace the value in the hours index
      timeUnit[0] = timeUnit[0] % 12 || 12;
    }
    // return adjusted time or original string
    return timeUnit.join('');
  });
  // Re-assemble the array pieces into a string
  return parseTime.join(' ');
};


console.log(formatMonthDayYearTime('Sat 9/17/18 18:30'));
// console log returns the following
// Mon 9/17/18 6:30pm

console.log(militaryToTweleveHourConverter('18:30'));
// console log returns the following
// 6:30pm

console.log(militaryToTweleveHourConverter('18:30:09'));
// console log returns the following
// 6:30:09pm

console.log(militaryToTweleveHourConverter('8:30:09'));
// console log returns the following
// 8:30:09am

Answer 21

This might help to format if you are using ES6.
Below code snippet will ignore the seconds. If you want to consider seconds you can add that as the first parameter.

   const formatFrom24Hrsto12Hrs = (time, ignoreZero = true) => {
      let [hours, minutes] = time.split(':')
      let modifier = +hours < 12 ? 'am' : 'pm'
      hours = +hours % 12 || 12
      minutes = ignoreZero && +minutes === 0 ? '' : `:${minutes}`
      return hours + minutes + modifier
    }

Answer 22

Here's my way using if statements.

const converTime = (time) => {
  let hour = (time.split(':'))[0]
  let min = (time.split(':'))[1]
  let part = hour > 12 ? 'pm' : 'am';
  
  min = (min+'').length == 1 ? `0${min}` : min;
  hour = hour > 12 ? hour - 12 : hour;
  hour = (hour+'').length == 1 ? `0${hour}` : hour;

  return (`${hour}:${min} ${part}`)
}

console.log(converTime('18:00:00'))
console.log(converTime('6:5:00'))

Answer 23

Here's a few variations that will work.

const oneLiner = (hour = "00", min = "00", sec = "00") => `${(hour % 12) || 12}:${("0" + min).slice(-2)}:${sec} ${(hour < 12) ? 'am' : 'pm'}`
console.log('oneliner', oneLiner(..."13:05:12".split(":")))



const oneLinerWithObjectInput = ({hour = "00", min = "00", sec = "00"} = {}) => `${(hour % 12) || 12}:${("0" + min).slice(-2)}:${sec} ${(hour < 12) ? 'am' : 'pm'}`
console.log('onelinerWithObjectInput', oneLinerWithObjectInput({
   hour: "13:05:12".split(":")[0],
   min: "13:05:12".split(":")[1],
   sec: "13:05:12".split(":")[2]
}))


const multiLineWithObjectInput = ({hour = "00", min = "00", sec = "00"} = {}) => {
   const newHour = (hour % 12) || 12
       , newMin  = ("0" + min).slice(-2)
       , ampm    = (hour < 12) ? 'am' : 'pm'
   return `${newHour}:${newMin}:${sec} ${ampm}`
}
console.log('multiLineWithObjectInput', multiLineWithObjectInput({
   hour: "13:05:12".split(":")[0],
   min: "13:05:12".split(":")[1],
   sec: "13:05:12".split(":")[2]
}))

Answer 24

Make sure that your time is in this format HH:MM:SS(PM/AM)

function timeConversion(s) {

    s = s.split(':');
    var time = s[2];
    if(time.charAt(2) === 'A' && parseInt(s[0]) == 12) s[0] = '00';
    if(time.charAt(2) === 'P' && parseInt(s[0]) <12) s[0] = parseInt(s[0])+12;
    if(s[0] >=24) s[0]-=24;
    var x = time.split('').slice(0,2);
    s[2] = x.join('');
    console.log(s.join(':'));
}

Answer 25

Based on gilly3's answer.

If you want to convert:

 08:00 to 08:00 AM 
 16:00 to 04:00 PM

Then this will work:

function tConv24(time24) {
  var ts = time24;
  var H = +ts.substr(0, 2);
  var h = (H % 12) || 12;
  h = (h < 10)?("0"+h):h;  // leading 0 at the left for 1 digit hours
  var ampm = H < 12 ? " AM" : " PM";
  ts = h + ts.substr(2, 3) + ampm;
  return ts;
};

https://jsfiddle.net/fpjs9g0L/

Answer 26

Assuming you will get the date string in a proper format, I have a solution.

function parseDateTime(dt) {
        var date = false;
        if (dt) {
            var c_date = new Date(dt);
            var hrs = c_date.getHours();
            var min = c_date.getMinutes();
            if (isNaN(hrs) || isNaN(min) || c_date === "Invalid Date") {
                return null;
            }
            var type = (hrs <= 12) ? " AM" : " PM";
            date = ((+hrs % 12) || hrs) + ":" + min + type;
        }
        return date;
    }

    parseDateTime("2016-11-21 12:39:08");//"12:39 AM"
    parseDateTime("2017-11-21 23:39:08");//"11:39 PM"

Answer 27

Researching this same question I have come across several complicated, hard to understand solutions, and then it dawned on me: There is a very simple solution that doesn't rely on hard-to-read regular expressions or other complicated code. Unless I am missing something obvious, this is an extremely simple, easy to understand solution:

function timeTo12HrFormat(time)
{   // Take a time in 24 hour format and format it in 12 hour format
    var time_part_array = time.split(":");
    var ampm = 'AM';

    if (time_part_array[0] >= 12) {
        ampm = 'PM';
    }

    if (time_part_array[0] > 12) {
        time_part_array[0] = time_part_array[0] - 12;
    }

    formatted_time = time_part_array[0] + ':' + time_part_array[1] + ':' + time_part_array[2] + ' ' + ampm;

    return formatted_time;
}



var time = timeTo12HrFormat(18:00:00);
console.log(time);  // 6:00:00 PM