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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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21 Answers 21

up vote 31 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[])]"
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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 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 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 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 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 at 20:42

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

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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

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.

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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';
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... 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


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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

As of 28th of July 2015 you can get this information via CloudWatch.

 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.

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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.

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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 at 18:30

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
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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"}'
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Provide the link to where amazon actually states this please. I can't find it. –  lobi Jul 31 at 17:30

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

s3cmd du -H s3://Mybucket
97G      s3://Mybucket/
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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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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
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I wrote a tool for analysing bucket size:

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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

More info and full script here :

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

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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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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;
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