In this blog I would like to explain about what are storage classes in AWS S3. How can these Storage classes reduce cost of storing our data in S3.

In this blog I will be covering different types of storage classes and difference between Glacier vault based storage & S3 Glacier

AWS offers a wide range of storage classes that trade retrieval time , accessibility and durability for a cheaper storage.

As of 2025 there are total 8 Storage classes.

1. S3 Standard

2. S3 Standard Infrequent Access (IA)

3. Express One Zone

4. S3 One Zone IA

5. S3 Glacier Instant Retrieval

6. S3 Glacier Flexible Retrieval

7. S3 Glacier Deep Archive.

8. S3 Intelligent Tiering

Now Let’s us know about them, in detail.

S3 Standard

This is the default storage class , when you upload a object to S3 bucket. This storage class is for frequently accessed data.

Durability: 99.99999999999% (11 9’s )

High Availability: 99.99% 99.99% availability means that S3 Standard is designed to be unavailable for no more than about 52.56 minutes per year (calculated as 0.01% of 365 days). This makes it highly reliable for frequently accessed data, such as active workloads or applications.

Durability v/s Availability

Durability ensures your data isn’t lost due to hardware failures, corruption, or other issues over time.

Availability ensures that you can access your data when you want it, without delays or outages.

Data Redundancy : Data is stored in multiple ( 3 or more ) availability zones to ensure high availability.

Retrieval Time: With in milliseconds (low latency)

Higher throughput : Optimized for data that is frequently accessed or requires real time access.

Scalability: Easily scales to number of requests and storage size.

Use Cases: This storage class is ideal for content distribution, big data analytics, gaming , where frequent access is required.

Price:

1. Per GB ~$0.023/GB/month

2. Per Requests ~ $0.0004/1,000 GET requests

3. No Retrieval fee

4. No Minimum Storage duration charge.

S3 Standard IA

This storage class is designed for data that is less frequently accessed but requires rapid access when needed .

Durability : 99.99999999999% ( 11 9’s ) like S3 Standard.

Availability : 99.9 % slower when compared with S3 Standard.

Data Redundancy : Data is stored in multiple ( 3 or more ) availability zones.

This Storage class costs 50% less than S3 Standard. As long as you don’t access data once a month.

Retrieval Time : with in ms

High throughput : Optimized for rapid access.

Scalability : Same as S3 Standard.

Use Cases: Disaster Recovery , backups , long term data stores , where data is not frequently stored.

Price:

1. Per GB ~$0.0125/GB/month

2. Per Requests ~$0.001/1,000 GET requests

3. Retrieval fee ~$0.01/GB retrieved

4. 30 days minimum Storage duration charge . Data must be present at least for 30 days. Accessed at most per 1 month.

5. Minimum Object Size is 128 KB.

When to use this storage class?

• Your data is accessed less than once a month but needs immediate availability.

• You want to reduce costs compared to S3 Standard without sacrificing performance.

S3 Express One Zone

This Storage class is designed for high-performance, it is a single AZ storage for latency-sensitive, frequently accessed data, sacrificing redundancy for speed and support for hundreds of thousands of requests per second.

Data accessed extremely frequent (multiple times/second) and single-digit milliseconds (up to 10x faster) than S3 Standard

Uses "directory buckets," a new S3 bucket type optimized for performance.

This storage class is Single-AZ, risk of data loss if the AZ fails—use for non-critical or replicated data.

Availability : 99.95%

Data Redundancy: Data is stored in one AZ

Price:

1. Per GB ~$0.16/GB/month

2. Per Requests ~$0.0002/1,000 GET requests (50% less than S3 Standard)

3. No Retrieval fee

4. Minimum Storage Duration is 1 hr

5. No Minimum Object Size

   When to use this storage class?

   Data is short-lived and your data is blazing hot (accessed constantly) and performance is the top priority.

S3 One Zone IA

This Storage Class is designed for the data that is less frequently accessed and has additional saving at reduced availability.

Availability: 99.5%

Price:

1. Per GB ~$0.01/GB/month ( 20%<Standard IA)

2. Per Request ~$0.001/1,000 GET requests

3. Retrieval Fee ~$0.01/GB retrieved

4. Minimum Storage duration is 30 days.

5. Minimum Object Size is 128 KB.

When to use this storage class?

Ideal for secondary backups or temporary snapshots that can be recreated. Non-critical data, that is infrequently accessed.

S3 Glacier Instant Retrieval

This Storage Class is designed for rarely accessed data, that requires immediate, millisecond-latency retrieval. This Storage class is for long lived data which is accessed once in a quarter.

Availability: 99.9%

Price:

1. Per GB ~$0.004/GB/month ( 82% < Standard)

2. Per Requests ~$0.01/1,000 GET requests

3. Retrieval Fees ~$0.03/GB retrieved (30% > IA)

4. Minimum Storage duration is 90 days.

5. Minimum Object Size is 128KB

When to use this storage class?

Very infrequent access (e.g., a few times a year), immediate retrieval required, multi-AZ durability needed.

Healthcare: Medical imaging (e.g., MRIs, X-rays) stored long-term but retrieved instantly during patient visits.

Media Archives: Rarely accessed high-value content (e.g., broadcast masters, historical footage) needing instant playback.

Digital Preservation: Legal documents or scientific data accessed sporadically but requiring millisecond latency.

Content Libraries: Stock photos/videos accessed occasionally by users.

S3 Glacier Flexible Retrieval

This Storage class is designed for very rarely accessed data (e.g., once or twice a year) with flexible retrieval options, balancing cost and retrieval time.

Availability : 99.9%

• Objects are stored in an archival format and must be restored to the S3 bucket before they can be accessed. This involves initiating a retrieval job, after which the data is temporarily copied to S3 Standard for access.

• You specify a retrieval tier (Expedited, Standard, or Bulk), which determines the speed and cost.

S3 Glacier Flexible Retrieval offers three retrieval options based on your needs:

1. Expedited Retrieval

   • Retrieval time: 1–5 minutes.

   • Best for urgent data access.

   • Limited to 250MB object size.

   • ~$0.03 per GB retrieved

2. Standard Retrieval

   • Retrieval time: 3–5 hours.

   • Suitable for regular retrieval needs.

   • No Archival size limit , this is default.

   • ~$0.02 per GB retrieved

3. Bulk Retrieval

   • Retrieval time: 5–12 hours.

   • Best for retrieving large datasets cost-effectively.

   • No archival size limit.

   • ~$0.0025 per GB retrieved

• Wait for the job to complete (duration depends on the tier).

• Once restored, access the object in S3 Standard using GET requests for a specified duration (e.g., 1-30 days, configurable).

• After the retention period, the restored copy expires unless extended.

Price:

1. Per GB ~$0.0036/GB/month ( 86% < Standard)

2. Per Requests ~$0.05 per 1,000 retrieval requests.

3. Retrieval Fee ( Depends on Tier )

4. Minimum object duration is 90 days.

5. NO Minimum Object Size but a 40 KB Over head

You have to store fewer and larger files instead of smaller files.

When to use this storage class?

Same as Glacier Instant Retrieval but delayed retrievals.

• Long-Term Archives: Compliance data (e.g., tax records) accessed once every few years.

• Media Backups: Cold storage for video masters or raw footage retrieved infrequently (e.g., bulk restores).

• Disaster Recovery: Tertiary backups accessed only in emergencies, tolerating hours-long retrieval.

S3 Glacier Deep Archive

This Storge is designed for extremely rare access (e.g., once every few years) with the lowest storage cost in AWS, ideal for long-term retention and compliance.

Availability: 99.9%

• Similar to Flexible Retrieval, objects are stored in a deep archival format and require a restoration job to make them accessible in S3 Standard. However, retrieval times are longer due to its ultra-low-cost design for extremely rare access.

• Only two tiers are available: Standard and Bulk (no Expedited option)

  • Standard: ~$0.02/GB.

  • Bulk: ~$0.0025/GB.

Same as Glacier Flexible Retrieval.

Price:

1. Per GB ~$0.00099/GB/month ( 95.7% < Standard )

2. Per Requests ~$0.05 per 1,000 retrieval requests.

3. Retrieval Fee ( Depends on tier )

4. Minimum object duration is 180 days.

5. NO Minimum Object Size but a 40 KB Over head

When to use this storage class?

A bank storing 10 years of transaction logs (100 TB) for SEC compliance

Museums, libraries, media companies, and research institutions need to preserve historical or cultural assets.

S3 Intelligent Tiering

This storage class designed to optimize costs by automatically moving objects between different storage classes based on changing access patterns. It’s ideal for workloads where access frequency is unknown, unpredictable.

There are no retrieval fees for accessing data within Intelligent-Tiering, only the standard request costs (e.g., GET, PUT), and no additional fees for moving data between its tiers.

Firstly this storage class puts object in S3 Standard Storage Class.

All objects start here. Data stays in this tier as long as it’s accessed regularly.

Next objects move to S3 Standard IA after 30 consecutive days of no access, saving ~45.7% compared to S3 Standard.

Next Objects move to Glacier Instant Retrieval after 90 consecutive days of no access, saving ~82.6% compared to Frequent Access.

Next Objects that hasn’t been accessed for 90 days or more (optional). moves to Glacier Flexible Retrieval
Data that hasn’t been accessed for 180 days or more (optional) moves to Deep Archive Access Tier

If the size of an object is less than 128 KB, it is not monitored and not eligible for auto-tiering. Smaller objects can be stored, but they are always charged at the Frequent Access tier rates in the S3 Intelligent-Tiering storage class.

Price:

1. Per GB ( Depends on Storage Class )

2. Per Requests ( Depends on Storage Class)

3. Retrieval Fee ( Depends on Storage Class )

4. Monitoring and Automation Fees : $0.0025/1,000 objects/month monitoring, $0.01/1,000 transitions.

(This fee applies only to objects stored in Frequent or IA tiers — no monitoring fees apply for Archive tiers.)

5. Minimum Object Size 128 KB

Lets have a Over view of what we have learned till now.

That’s it on a over view of AWS storage class .

We’ll learn about Glacier vault based storage and S3 Glacier in next blog.

Thanks for reading my blog. Have a great day 🎉🎉🎉