vercel-ms

vercel/ms — Millisecond Conversion Utility

Tiny utility (zero deps) that converts between millisecond numbers and human-readable time strings.

Install

npm install ms

Core API

import { ms, parse, format, parseStrict } from 'ms';

ms(string) → number

Parse a time string into milliseconds:

ms('2 days')   // 172800000
ms('1d')       // 86400000
ms('10h')      // 36000000
ms('2.5 hrs')  // 9000000
ms('1m')       // 60000
ms('5s')       // 5000
ms('1y')       // 31557600000
ms('-3 days')  // -259200000
ms('100')      // 100  (no unit → treated as ms)

ms(number) → string

Format milliseconds into a short string:

ms(60000)           // "1m"
ms(2 * 60000)       // "2m"
ms(-3 * 60000)      // "-3m"
ms(ms('10 hours'))  // "10h"

ms(number, { long: true }) → string

Format milliseconds into a verbose string:

ms(60000, { long: true })          // "1 minute"
ms(2 * 60000, { long: true })      // "2 minutes"
ms(ms('10 hours'), { long: true }) // "10 hours"

parse(str) / format(ms, options?)

Import separately when you only need one direction:

import { parse, format } from 'ms';

parse('1h')  // 3600000
format(2000) // "2s"
format(2000, { long: true }) // "2 seconds"

parseStrict(value: StringValue)

Like parse, but enforces TypeScript's StringValue type — rejects arbitrary strings at compile time:

import { parseStrict } from 'ms';

parseStrict('1h') // 3600000

function foo(s: string) {
  return parseStrict(s) // tsc error — s is not StringValue
}

Supported Units

Unit	Accepted strings
Years	years year yrs yr y
Months	months month mo
Weeks	weeks week w
Days	days day d
Hours	hours hour hrs hr h
Minutes	minutes minute mins min m
Seconds	seconds second secs sec s
Milliseconds	milliseconds millisecond msecs msec ms