Is there a way to round numbers in a reader friendly format? (e.g. 1.1 thousand US dollars)

Question

As with Stackoverlow's reputation, I hope to do the same with currency

$ 1000 => 1 thousand

1,000,000 = 1 million

How can I achieve this in JavaScript (preferably in jQuery)?

Answer 1

Here is a simple function:

function abbrNum(number, decPlaces) { // 2 decimal places => 100, 3 => 1000, etc decPlaces = Math.pow(10,decPlaces); // Enumerate number abbreviations var abbrev = [ "k", "m", "b", "t" ]; // Go through the array backwards, so we do the largest first for (var i=abbrev.length-1; i>=0; i--) { // Convert array index to "1000", "1000000", etc var size = Math.pow(10,(i+1)*3); // If the number is bigger or equal do the abbreviation if(size <= number) { // Here, we multiply by decPlaces, round, and then divide by decPlaces. // This gives us nice rounding to a particular decimal place. number = Math.round(number*decPlaces/size)/decPlaces; // Handle special case where we round up to the next abbreviation if((number == 1000) && (i < abbrev.length - 1)) { number = 1; i++; } // Add the letter for the abbreviation number += abbrev[i]; // We are done... stop break; } } return number; } 

Outputs:

 abbrNum(12 , 1) => 12 abbrNum(0 , 2) => 0 abbrNum(1234 , 0) => 1k abbrNum(34567 , 2) => 34.57k abbrNum(918395 , 1) => 918.4k abbrNum(2134124 , 2) => 2.13m abbrNum(47475782130 , 2) => 47.48b 

Demo: http://jsfiddle.net/jtbowden/SbqKL/

Answer 2

 var pow = Math.pow, floor = Math.floor, abs = Math.abs, log = Math.log; var abbrev = 'kmb'; // could be an array of strings: [' m', ' Mo', ' Md'] function round(n, precision) { var prec = Math.pow(10, precision); return Math.round(n*prec)/prec; } function format(n) { var base = floor(log(abs(n))/log(1000)); var suffix = abbrev[Math.min(2, base - 1)]; base = abbrev.indexOf(suffix) + 1; return suffix ? round(n/pow(1000,base),2)+suffix : ''+n; } 

Demo version:

 > tests = [-1001, -1, 0, 1, 2.5, 999, 1234, 1234.5, 1000001, Math.pow(10,9), Math.pow(10,12)] > tests.forEach(function(x){ console.log(x,format(x)) }) -1001 "-1k" -1 "-1" 0 "0" 1 "1" 2.5 "2.5" 999 "999" 1234 "1.23k" 1234.5 "1.23k" 1000001 "1m" 1000000000 "1b" 1000000000000 "1000b"