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I'd like to graph the size (in bytes, and # of items) of an Amazon S3 bucket and am looking for an efficient way to get the data.

The s3cmd tools provide a way to get the total file size using s3cmd du s3://bucket_name, but I'm worried about its ability to scale since it looks like it fetches data about every file and calculates its own sum. Since Amazon charges users in GB-Months it seems odd that they don't expose this value directly.

Although Amazon's REST API returns the number of items in a bucket, [s3cmd] doesn't seem to expose it. I could do s3cmd ls -r s3://bucket_name | wc -l but that seems like a hack.

The Ruby AWS::S3 library looked promising, but only provides the # of bucket items, not the total bucket size.

Is anyone aware of any other command line tools or libraries (prefer Perl, PHP, Python, or Ruby) which provide ways of getting this data?

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I wrote a tool for analysing bucket size: – omribahumi Sep 20 '15 at 7:10
I am astonished that Amazon charge for the space, but don't provide the total size taken up by an S3 bucket simply through the S3 panel. – Luke Dec 10 '15 at 10:42

25 Answers 25

up vote 74 down vote accepted

The AWS CLI now supports the --query parameter which takes a JMESPath expressions.

This means you can sum the size values given by list-objects using sum(Contents[].Size) and count like length(Contents[]).

This can be be run using the official AWS CLI as below and was introduced in Feb 2014

 aws s3api list-objects --bucket BUCKETNAME --output json --query "[sum(Contents[].Size), length(Contents[])]"
share|improve this answer
For large buckets (large #files), this is excruciatingly slow. The Python utility s4cmd "du" is lightning fast: s4cmd du s3://bucket-name – Rubistro Mar 31 '15 at 22:08
That's strange. What is the overall profile of your bucket (shallow and fat / deep and thin)? It looks like s3cmd should have the same overheads as AWS CLI. In the code it shows s3cmd make a request for each directory in a bucket. – Christopher Hackett Apr 1 '15 at 15:14
to get it in human readable format: aws s3api --profile PROFILE_NAME list-objects --bucket BUCKET_NAME --output json --query "[sum(Contents[].Size), length(Contents[])]" | awk 'NR!=2 {print $0;next} NR==2 {print $0/1024/1024/1024" GB"}' – Sandeep Aug 8 '15 at 23:22
@Rubistro for me the aws cli with --query is a lot faster than s3cmd, but still this solution is not yet ideal... – Sebastien Lorber Sep 17 '15 at 15:56
Now that AWS Cloudwatch offers a "BucketSizeBytes" per-bucket metric this is no longer the right solution. See Toukakoukan's answer below. – cce Sep 24 '15 at 20:42

Since it's the first result for google, I reply later. s3cmd can do this : s3cmd du s3://bucket-name

share|improve this answer
Thanks. Here's some timing. On a bucket that holds an s3ql deduplicated filesystem with about a million files using about 33 GB of undupicated data, and about 93000 s3 objects, s3cmd du took about 4 minutes to compute the answer. I'm curious to know how that compares with other approaches like the php one described elsewhere here. – nealmcb Jul 10 '12 at 23:46
It is slow because the S3 ListObjects API call returns objects in pages of 1000 objects. As I/O is by far the limiting factor I think any solution will be relatively slow over 93000 objects. – David Caunt Apr 20 '13 at 13:54
s4cmd can also do the same thing, with the added benefit of multi-threading the requests to S3's API to compute the result faster. The tool hasn't been updated recently, but the Internet passer-by may find it useful. – Nick Chammas Jul 7 '14 at 17:34
s4cmd just returns 0 for me, and returns BotoClientError: Bucket names cannot contain upper-case characters when using either the sub-domain or virtual hosting calling format. for buckets with uppercase characters. – Lakitu Oct 5 '15 at 20:52

This can now be done trivially with just the official AWS command line client:

aws s3 ls --summarize --human-readable --recursive s3://bucket-name/

Official documentation

This also accepts path prefixes if you don't want to count the entire bucket:

aws s3 ls --summarize --human-readable --recursive s3://bucket-name/directory
share|improve this answer
This is the best and up-to date answer – Tim Apr 5 at 22:26
Agree, this is the best answer. – Luis Artola Jul 5 at 17:28
This is very slow for buckets with many files as it basically lists all the objects in the bucket before showing the summary, and in that it is not significantly faster than the @Christopher Hackett's answer - except this one is much more noisy. – Guss Jul 24 at 23:19

As of 28th of July 2015 you can get this information via CloudWatch. If you want a GUI, go to the CloudWatch console: (Choose Region > ) Metrics > S3


This is much quicker than some of the other commands posted here, as it does not query the size of each file individually to calculate the sum.

 aws cloudwatch get-metric-statistics --namespace AWS/S3 --start-time 2015-07-15T10:00:00 --end-time 2015-07-31T01:00:00 --period 86400 --statistics Average --region eu-west-1 --metric-name BucketSizeBytes --dimensions Name=BucketName, Name=StorageType,Value=StandardStorage

Important: You must specify both StorageType and BucketName in the dimensions argument otherwise you will get no results. All you need to change is the --start-date, --end-time, and

Here's a convenience bash script you can use to avoid having to specify --start-date and --end-time manually.

now=$(date +%s)
aws cloudwatch get-metric-statistics --namespace AWS/S3 --start-time "$(echo "$now - 86400" | bc)" --end-time "$now" --period 86400 --statistics Average --region eu-west-1 --metric-name BucketSizeBytes --dimensions Name=BucketName,Value="$bucket" Name=StorageType,Value=StandardStorage
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Or in the CloudWatch console: (Choose Region > ) Metrics > S3 – Halil Özgür Jan 7 at 17:57

If you download a usage report, you can graph the daily values for the TimedStorage-ByteHrs field.

If you want that number in GiB, just divide by 1024 * 1024 * 1024 * 24 (that's GiB-hours for a 24-hour cycle). If you want the number in bytes, just divide by 24 and graph away.

share|improve this answer

I used the S3 REST/Curl API listed earlier in this thread and did this:

if (!class_exists('S3')) require_once 'S3.php';

// Instantiate the class
$s3 = new S3('accessKeyId', 'secretAccessKey');
S3::$useSSL = false;

// List your buckets:
echo "S3::listBuckets(): ";
echo '<pre>' . print_r($s3->listBuckets(), 1). '</pre>';

$totalSize = 0;
$objects = $s3->getBucket('name-of-your-bucket');
foreach ($objects as $name => $val) {
    // If you want to get the size of a particular directory, you can do
    // only that.
    // if (strpos($name, 'directory/sub-directory') !== false)
    $totalSize += $val['size'];

echo ($totalSize / 1024 / 1024 / 1024) . ' GB';
share|improve this answer

s4cmd is the fastest way I've found (a command-line utility written in Python):

pip install s4cmd

Now to calculate the entire bucket size using multiple threads:

s4cmd du s3://bucket-name
share|improve this answer
No, s4cmd du s3://123123drink will not simply return the size of the bucket. To get the size of the bucket you do add the recursive -r, like this: s4cmd du -r s3://123123drink – Buk Lau Nov 9 '15 at 16:12

Using the official AWS s3 command line tools:

aws s3 ls s3://bucket/folder --recursive | awk 'BEGIN {total=0}{total+=$3}END{print total/1024/1024" MB"}'
share|improve this answer
Provide the link to where amazon actually states this please. I can't find it. – lobi Jul 31 '15 at 17:30

So trolling around through the API and playing some same queries, S3 will produce the entire contents of a bucket in one request and it doesn't need to descend into directories. The results then just requiring summing through the various XML elements, and not repeated calls. I don't have a sample bucket that has thousands of items so I don't know how well it will scale, but it seems reasonably simple.

share|improve this answer
This does seem to be the best option. Will update this post in the future if it scales poorly and I need to do something else. The library that ended up providing easy access to the raw API results was this PHP one: – Garret Heaton Nov 16 '09 at 15:20
Isn't that only limited to the first 1000 items? – Charlie S Apr 13 '15 at 18:30

... A bit late but, the best way I found is by using the reports in the AWS portal. I made a PHP class for downloading and parsing the reports. With it you can get total number of objects for each bucket, total size in GB or byte hrs and more.

Check it out and let me know if was helpful


share|improve this answer
This is an interesting solution, although a little hackish. Worried about it breaking if/when Amazon changes their site, but I may have to try this out once I have enough objects that the other way becomes too slow. Another benefit of this approach is that you don't get charged for any API calls. – Garret Heaton Dec 21 '09 at 16:16
. . . its an assumption but, if Amazon do change the look of their site, I doubt they would change the back end much, meaning the current GET and POST queries should work. I will maintain the class in the event it does break anyway as I use it often. – Corey Sewell Dec 22 '09 at 0:26

You can use the s3cmd utility, e.g.:

s3cmd du -H s3://Mybucket
97G      s3://Mybucket/
share|improve this answer

For a really low-tech approach: use an S3 client that can calculate the size for you. I'm using Panic's Transmit, click on a bucket, do "Get Info" and click the "Calculate"-button. I'm not sure how fast or accurate it is in relation to other methods, but it seems to give back the size I had expected it to be.

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I recommend using S3 Usage Report for large buckets, see my How To on how to get it Basically you need to download Usage Report for S3 service for the last day with Timed Storage - Byte Hrs and parse it to get disk usage.

cat report.csv | awk -F, '{printf "%.2f GB %s %s \n", $7/(1024**3 )/24, $4, $2}' | sort -n
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The AWS documentation tells you how to do it:

aws s3 ls s3://bucketnanme --recursive --human-readable --summarize

This is the output you get:

2016-05-17 00:28:14    0 Bytes folder/
2016-05-17 00:30:57    4.7 KiB folder/file.jpg
2016-05-17 00:31:00  108.9 KiB folder/file.png
2016-05-17 00:31:03   43.2 KiB folder/file.jpg
2016-05-17 00:31:08  158.6 KiB folder/file.jpg
2016-05-17 00:31:12   70.6 KiB folder/file.png
2016-05-17 00:43:50   64.1 KiB folder/folder/folder/folder/file.jpg

Total Objects: 7

   Total Size: 450.1 KiB
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Hey there is a metdata search tool for AWS S3 at tool gives statstics about objects in a bucket with search on metadata.

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Also Hanzo S3 Tools does this. Once installed, you can do:

s3ls -s -H bucketname

But I believe this is also summed on the client side and not retrieved through the AWS API.

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By Cloudberry program is also possible to list the size of the bucket, amount of folders and total files, clicking "properties" right on top of the bucket.

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I know this is an older question but here is a PowerShell example:

Get-S3Object -BucketName <buckename> | select key, size | foreach {$A += $_.size}

$A contains the size of the bucket, and there is a keyname parameter if you just want the size of a specific folder in a bucket.

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If you don't want to use the command-line, on Windows and OSX, there's a general purpose remote file management app called Cyberduck. Log into S3 with your access/secret key pair, right-click on the directory, click Calculate.

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I wrote a Bash script, that will list files in bucket with s3ls, and print count of files, and sizes like
149 files in bucket
11760850920 B
11485205 KB
11216 MB
10 GB

Full script:


if [ “${1}” ]
for N in `s3ls ${1} | awk ‘{print $11}’ | grep [0-9]`
NUM=`expr $NUM + $N`
KB=`expr ${NUM} / 1024`
MB=`expr ${NUM} / 1048576`
GB=`expr ${NUM} / 1073741824`
echo “${COUNT} files in bucket ${1}”
echo “${NUM} B”
echo “${KB} KB”
echo “${MB} MB”
echo “${GB} GB”
echo “Usage : ${0} s3-bucket”
exit 1

It does do subdirectory size, as Amazon returns the directory name and the size of all of it's contents.

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Since there are so many answers, I figured I'd pitch in with my own. I wrote my implementation in C# using LINQPad. Copy, paste, and enter in the access key, secret key, region endpoint, and bucket name you want to query. Also, make sure to add the AWSSDK nuget package.

Testing against one of my buckets, it gave me a count of 128075 and a size of 70.6GB. I know that is 99.9999% accurate, so I'm good with the result.

void Main() {
    var s3Client = new AmazonS3Client("accessKey", "secretKey", RegionEndpoint.???);
    var stop = false;
    var objectsCount = 0;
    var objectsSize = 0L;
    var nextMarker = string.Empty;

    while (!stop) {
        var response = s3Client.ListObjects(new ListObjectsRequest {
            BucketName = "",
            Marker = nextMarker

        objectsCount += response.S3Objects.Count;
        objectsSize += response.S3Objects.Sum(
            o =>
        nextMarker = response.NextMarker;
        stop = response.S3Objects.Count < 1000;

    new {
        Count = objectsCount,
        Size = objectsSize.BytesToString()

static class Int64Extensions {
    public static string BytesToString(
        this long byteCount) {
        if (byteCount == 0) {
            return "0B";

        var suffix = new string[] { "B", "KB", "MB", "GB", "TB", "PB", "EB" };
        var longBytes = Math.Abs(byteCount);
        var place = Convert.ToInt32(Math.Floor(Math.Log(longBytes, 1024)));
        var number = Math.Round(longBytes / Math.Pow(1024, place), 1);

        return string.Format("{0}{1}", Math.Sign(byteCount) * number, suffix[place]);
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To check all buckets size try this bash script

s3list=`aws s3 ls | awk  '{print $3}'`
for s3dir in $s3list
    echo $s3dir
    aws s3 ls "s3://$s3dir"  --recursive --human-readable --summarize | grep "Total Size"
share|improve this answer

You can use s3cmd:

s3cmd du s3://Mybucket -H


s3cmd du s3://Mybucket --human-readable

It gives the total objects and the size of the bucket in a very readable form.

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Following way uses AWS PHP SDK to get the total size of the bucket.

// make sure that you are using correct region (where the bucket is) to get new Amazon S3 client
$client = \Aws\S3\S3Client::factory(array('region' => $region));

// check if bucket exists
if (!$client->doesBucketExist($bucket, $accept403 = true)) {
    return false;
// get bucket objects
$objects = $client->getBucket(array('Bucket' => $bucket));

$total_size_bytes = 0;
$contents = $objects['Contents'];

// iterate through all contents to get total size
foreach ($contents as $key => $value) {
   $total_bytes += $value['Size'];
$total_size_gb = $total_size_bytes / 1024 / 1024 / 1024;
share|improve this answer

This works for me..

aws s3 ls s3://bucket/folder/ --recursive | awk '{sz+=$3} END {print sz/1024/1024 "MB"}'
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Can you add a few more details ? – Pierre.Vriens Apr 14 at 20:08
This is essentially the same solution as another answer posted about a year earlier. – Louis May 2 at 11:41

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