ElastiCache Serverless Pricing: The Complete 2026 Guide

Sources: Redis OSS rates ($0.0034/million ECPUs, $0.125/GB-hr) from AWS Database Blog official worked example (aws.amazon.com/blogs/database/unlock-on-demand-cost-optimized-performance-with-amazon-elasticache-serverless/). Valkey rates ($0.0023/million ECPUs, $0.084/GB-hr) from pump.co (March 2025) citing AWS official. Verify at aws.amazon.com/elasticache/pricing/ — rates change.

Complete Serverless Pricing Table

All rates: US East (N. Virginia), October 15, 2026.

Backup $0.085/GiB-month from AWS official pricing page. Data transfer rates from AWS official. All other rates from AWS Database Blog official worked examples and pump.co (March 2025). Verify all at aws.amazon.com/elasticache/pricing/.

How ECPU Pricing Works

ECPU metering accounts for both CPU time and data transferred, with a baseline of one ECPU for a simple request. For simple reads and writes, ECPUs follow the KB transferred with a minimum of one ECPU per request. Valkey and Redis OSS commands that use more CPU are billed using the higher of CPU work or data transferred; Memcached multi-item requests can also use more ECPUs. A basic GET returning less than 1 KB, such as 500 bytes, consumes one ECPU. A GET returning 3.2 KB consumes 3.2 ECPUs. Source: AWS official pricing page: ‘Reads and writes require 1 ECPU for each kilobyte (KB) of data transferred.’

Commands that require additional vCPU time beyond basic data transfer — HSET with many fields, ZADD to large sorted sets, LRANGE over large lists, Lua scripts — consume proportionally more ECPUs than the 1-per-KB baseline. For most standard caching patterns (GET/SET of small JSON objects, session tokens, feature flags), ECPU consumption scales linearly and predictably with request rate and payload size.

For basic requests up to 1 KB, 10,000 requests/second × 3,600 = 36 million ECPUs/hour, not 36 billion. At $0.0034/million, Redis OSS costs $0.1224/hour or $89.352 ($89.35) per 730-hour month for ECPUs. Valkey at $0.0023/million costs $0.0828/hour or $60.444 ($60.44)/month. Storage is additional; complex commands can consume more.

The Minimum Storage Floor: Why Engine Choice Changes Everything for Dev Environments

The minimum metered data storage is billed regardless of how much data your cache actually holds. AWS samples storage multiple times per minute and calculates an hourly average — if you store 50 MB in a Redis OSS Serverless cache, you are billed for 1 GB (the minimum). If you store 50 MB in a Valkey Serverless cache, you are billed for 100 MB (the Valkey minimum).

Monthly floor cost comparison:

Redis OSS Serverless minimum: 1 GB x $0.125/GB-hr x 730 hrs = $91.25/month.

Valkey Serverless minimum: 0.1 GB x $0.084/GB-hr x 730 hrs = $6.13/month.

For ten near-empty caches, the storage floors are $912.50/month for Redis OSS and $61.32/month for Valkey, a difference of $851.18 before requests and other charges. Validate client and feature compatibility before migrating.

For compatible Redis OSS workloads, evaluate Valkey Serverless as a lower-priced option. Test supported commands, client TLS and cluster-mode support, cache warming, and cutover before changing endpoints. The lower published unit rates and minimum storage floor do not guarantee the same reduction in every application’s total bill.

Also read: ElastiCache Reserved Nodes: Complete Pricing Guide

Worked Example 1: Variable Traffic Application Cache (Illustrative Calculation)

Illustrative workload: 10 GB and 10,000 basic requests/second for 22 hours/day; 50 GB and 100,000 requests/second for two hours/day. Each basic request uses one ECPU. Average storage is (10 × 22 + 50 × 2)/24 = 13⅓ GB; average requests are 63 million ECPUs/hour.

Calculate the difference from unrounded amounts: $1,373.032666… − $923.377 = $449.655666… → $449.66. Comparing already rounded displayed totals can differ by one cent. These are modeled cache charges before backup, applicable transfer, monitoring and tax.

Worked Example 2: Simple GET/SET Cache at 50K RPS (Illustrative Calculation)

For 10 GB stored continuously and 50,000 basic requests/second, consumption is 180 million ECPUs/hour.

Both engines use the same request and storage assumptions. Do not round hourly cost to two decimal places before multiplying by 730.

Worked Example 3: Dev Cache Floor Cost Comparison

Scenario: 5 development caches, each storing 50 MB, receiving 100 requests per hour (essentially idle). This is the scenario where engine choice has the most dramatic impact.

Redis OSS Serverless — 5 caches at minimum 1 GB each: 5 x 1 GB x $0.125/GB-hr x 730 hrs = $456.25/month in storage alone. ECPU: negligible (100 requests/hr x 1 KB = 100 ECPUs/hr per cache = essentially $0). Total: $456.25/month for 5 empty dev caches.

Valkey Serverless — 5 caches at minimum 100 MB each: 5 x 0.1 GB x $0.084/GB-hr x 730 hrs = $30.66/month in storage alone. Total: $30.66/month for the same 5 empty dev caches.

Monthly saving by switching dev caches to Valkey: $425.59/month. Annualized storage-only saving: $5,107.08, assuming the same tenanted footprint for 12 months. Zero application changes required. Source: math from verified rates.

Rule of thumb for dev caches: always use Valkey Serverless. The 15x lower minimum storage floor makes it the default correct choice for any cache where the stored data is small relative to the Redis OSS 1 GB minimum. Reserve Redis OSS Serverless for the rare case where Redis-specific features absent from Valkey are required.

Serverless vs Node-Based: The Break-Even Point

Compare equivalent capacity, availability and traffic. In the 10-GB, 50,000-RPS example, Redis OSS Serverless is $1.862/hour and Valkey Serverless is $1.254/hour. A single node is not automatically equivalent to Serverless high availability.

As a node-cost illustration, two cache.r7g.xlarge nodes (one primary, one replica) cost $0.874/hour on Redis OSS or $0.6992/hour on Valkey. Over 730 hours those node charges are $638.02 and $510.42 respectively, before transfer and other charges. The raw difference against the modeled Serverless bill is $721.24/month for Redis OSS or $405.00/month for Valkey; this is not proven net savings until capacity and performance are validated.

Dataset size, headroom, replication, sustained request throughput, workload variability and cross-AZ transfer can change the result. Serverless VPC-endpoint traffic within the Region has no transfer fee; node-based application-side cross-AZ traffic can be charged. Benchmark both configurations before choosing.

Database Savings Plans for ElastiCache Serverless

Database Savings Plans cover eligible ElastiCache for Valkey usage. Redis OSS and Memcached must not be assumed eligible. Use the listed rate for each billable component; the overall program advertises up to 35% across supported database services, not a universal 30% discount for every cache.

Commitment is measured at discounted rates. In an explicitly hypothetical 30%-discount example, a perfectly stable $600/month On-Demand-equivalent eligible workload costs $420/month on the plan. At 730 hours, the corresponding commitment is $420/730 = about $0.57534/hour, not $600/730 = $0.82/hour. Full utilization would save $180/month or $2,160 over 12 modeled months. Actual quotes, hourly variability and existing coverage must be checked before committing.

Cost Optimization: Prioritized Actions

1. Switch all dev and staging caches from Redis OSS to Valkey Serverless

Compare Valkey’s lower unit prices and minimum storage floor for your Region. Validate client and command compatibility, warm or migrate the cache as needed, test the new endpoint, and keep a rollback path before retiring the old cache.

2. Right-size minimum storage expectations before choosing Serverless

If your cache will consistently store more than 10-15 GB, run the math: storage at $0.084/GB-hr (Valkey) x your GB x 730 hours. Compare against a node-based cluster that holds the same data. Beyond ~4-5 GB stored data at typical request rates, node-based clusters are often cheaper than Serverless.

3. Monitor average ECPUs from CloudWatch before committing

ElastiCache Serverless reports ECPUs consumed in CloudWatch. Pull 30 days of data, calculate average hourly ECPU cost, and compare against the equivalent node-based rate. If average hourly ECPU cost exceeds the on-demand node-hour rate for an equivalently sized node, migrate to node-based.

4. Evaluate Database Savings Plans for eligible Valkey usage

After 60 days of Serverless operation, you have reliable hourly spend data. Identify the consistent floor spend (the level your Serverless cost never drops below across all hours). Value eligible Valkey usage at its actual discounted rates before sizing the hourly commitment; leave headroom for workload reductions.

5. Delete idle Serverless caches, do not let them sit

Unlike Aurora DSQL (which scales to zero) or DocumentDB (where you can stop and resume), ElastiCache Serverless has no pause feature. An idle Serverless cache still bills at the storage minimum. Delete dev caches on Friday, recreate Monday. A Valkey cache recreates in under a minute and costs nothing between sessions. Source: AWS official documentation.

How Usage.ai Handles ElastiCache Serverless Costs

Usage.ai monitors ElastiCache Serverless ECPU and storage consumption from CloudWatch and surfaces the three highest-leverage optimization signals: Redis OSS caches where switching to Valkey would cut costs by 33%; Serverless caches at sustained throughput where node-based clusters would be cheaper; and Database Savings Plan sizing for eligible Valkey usage.

For teams running ElastiCache Serverless alongside node-based clusters, Usage.ai provides a unified cost view across both deployment modes. Reserved Nodes on node-based clusters (up to 55% savings) and Database Savings Plans on eligible Valkey usage are evaluated together to recommend the optimal commitment mix for the full ElastiCache spend. Fee: percentage of realized savings only.

See how Usage.ai optimizes ElastiCache Serverless and Reserved Node costs

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Frequently Asked Questions

1. How much does ElastiCache Serverless cost?

In US East (N. Virginia), Valkey costs $0.0023/million ECPUs plus $0.084/GB-hour; Redis OSS and Memcached cost $0.0034/million plus $0.125/GB-hour. At 10 GB and 50,000 basic one-ECPU requests/second, the 730-hour modeled totals are $915.42 for Valkey and $1,359.26 for Redis OSS, before other charges.

2. What are the exact ECPU rates for ElastiCache Serverless?

Valkey Serverless: $0.0023 per million ECPUs. Redis OSS Serverless: $0.0034 per million ECPUs. Memcached Serverless: $0.0034 per million ECPUs. Valkey is approximately 32% cheaper per ECPU. For simple reads and writes, one ECPU covers up to 1 KB, with larger transfers consuming proportionally more. CPU-intensive Valkey and Redis OSS commands use the higher of CPU work or transferred data; Memcached multi-item requests can also consume more. See AWS ECPU metering documentation and verify current regional unit rates at AWS pricing.

3. Why is Valkey cheaper than Redis OSS on ElastiCache Serverless?

AWS launched Valkey in October 2024 at 33% lower ECPU and storage rates, and with a 100 MB minimum stored versus 1 GB for Redis OSS. Valkey is an open-source, Redis-compatible fork maintained by the Linux Foundation. The pricing difference is permanent — not a promotional launch price. For teams not using Redis-specific features absent from Valkey (rare in practice), Valkey Serverless saves 33% immediately. Source: AWS Database Blog (October 2024) and AWS official pricing page.

4. What is the minimum cost for ElastiCache Serverless?

Valkey Serverless minimum: 100 MB metered storage = 0.1 GB x $0.084/GB-hr x 730 hrs = approximately $6.13/month (storage only, no ECPUs when idle). Redis OSS / Memcached Serverless minimum: 1 GB metered storage = 1 GB x $0.125/GB-hr x 730 hrs = approximately $91.25/month. There is no scale-to-zero — the minimum storage floor is always billed. Source: AWS official pricing page and verified rate calculations.

5. Are Reserved Nodes available for ElastiCache Serverless?

Reserved Nodes apply to node-based usage. Database Savings Plans can cover eligible ElastiCache for Valkey usage, subject to the exact quoted rates and a one-year hourly commitment. Do not assume Redis OSS or Memcached Serverless is covered.

6. When is node-based ElastiCache cheaper than Serverless?

Compare the complete cost of deployments that meet the same memory, throughput and availability requirements. A single node’s price is not a valid high-availability comparison. At the illustrative workload above, two r7g.xlarge nodes have lower node charges than Serverless, but transfer, headroom and performance must be tested before claiming net savings.