🗄️ Database Storage Cost Calculator

Database storage cost is easy to underestimate because the number that matters isn't your raw row count times row size — it's that figure plus index overhead plus however many replicas your provider keeps for durability and availability. This calculator walks through that full chain and prices the result across six common managed and self-managed storage options, so you can compare AWS RDS, Aurora, Google Cloud SQL, MongoDB Atlas, DynamoDB, and plain block storage on equal footing for the same dataset.

How It Works

Enter your number of rows and average row size in bytes to get raw data size. The calculator then adds your index overhead percentage (default 30%, typical for moderately indexed tables) to account for the extra storage indexes consume, and multiplies the result by your replication factor (1 for a single copy, 2 or 3 for high-availability setups with live replicas). That final "total size" figure is then multiplied by each provider's published per-GB-per-month storage rate — AWS RDS gp3 ($0.115/GB), Aurora storage ($0.10/GB), Google Cloud SQL ($0.17/GB), MongoDB Atlas dedicated tier (~$0.25/GB), DynamoDB standard ($0.25/GB), and self-managed block storage ($0.08/GB) — to produce a side-by-side monthly cost comparison.

Why It Matters

Storage pricing differences of 2-3× between providers compound quickly at scale — a 500 GB dataset costs roughly $40/month on self-managed block storage but over $125/month on MongoDB Atlas or DynamoDB, purely on storage. Factoring in index overhead and replication before comparing providers avoids the common mistake of budgeting only for raw data size and being surprised when the real bill (with indexes and replicas) turns out 50-100% higher than expected.

Tips for Accurate Results

• Index overhead varies widely by workload — a handful of simple B-tree indexes might only add 15-20%, while multiple composite indexes or full-text search indexes can add 50% or more.
• Only apply a replication factor above 1 if your billing model actually charges you for replica storage — some managed services (like Aurora) include a baseline of replication in the storage price already.
• This calculator estimates storage cost only — compute (instance hours), I/O operations, backup storage, and data transfer are typically separate line items on your actual bill.
• Re-check current provider pricing periodically, since storage rates do change and can vary by region, storage tier, and volume-based discounts.
• For rapidly growing datasets, model your projected row count 6-12 months out, not just today's size, to avoid under-budgeting for storage growth.