azurerm_snapshot cost estimation
A point-in-time copy of a managed disk, billed per GB-month. A 128 GB Standard LRS snapshot is ~$6.40/month.
An azurerm_snapshot is a point-in-time backup of an Azure managed disk. It's billed per GB-month of snapshot storage — Standard HDD (LRS) snapshots are ~$0.05/GB-month, so a 128 GB snapshot is ~$6.40/month. (Premium-backed snapshots and ZRS cost more.)
Azure snapshots are incremental by default: each snapshot of a disk stores only the blocks changed since the previous one, so a series of snapshots costs far less than the naive size × count. As with snapshots on any cloud, the cost problem is retention — automated snapshots with no cleanup accumulate, and because they share blocks, deleting old ones frees less than expected until the dependent chain is removed.
The levers: use incremental snapshots (the default) rather than full copies, store them in Standard (LRS) rather than premium/zone-redundant tiers unless you need the durability, set a retention policy that actually deletes old snapshots, and clean up snapshots of disks you've deleted.
c3x prices the snapshot from its disk size at the snapshot rate, so the per-snapshot cost — and the accumulation across a retention policy — is visible.
Terraform example
A minimal but realistic configuration that C3X can estimate.
resource "azurerm_snapshot" "backup" {
name = "data-disk-snapshot"
location = azurerm_resource_group.main.location
resource_group_name = azurerm_resource_group.main.name
create_option = "Copy"
source_resource_id = azurerm_managed_disk.data.id
incremental_enabled = true
}Pricing dimensions
What you actually pay for when you provision azurerm_snapshot.
| Dimension | Unit | What's being charged |
|---|---|---|
| Snapshot storage | per GB-month | Per GB-month at the snapshot rate (Standard LRS ~$0.05; premium/ZRS more). Incremental snapshots store only changed blocks. $0.05/GB-month → 128 GB ≈ $6.40/month |
Sample C3X output
A 128 GB Standard LRS snapshot:
azurerm_snapshot.backup
└─ Snapshot storage (Standard LRS) 128 GB-month $6.40
Monthly $6.40Optimization tips
Common ways to reduce azurerm_snapshot cost without changing the workload.
Use incremental snapshots
Large vs full snapshotsIncremental snapshots (incremental_enabled = true) store only blocks changed since the previous snapshot, so a daily snapshot series costs far less than full copies. The default and the right choice for most backups.
Store in Standard LRS unless you need more durability
Tier differenceStandard (LRS) is the cheapest snapshot tier. Premium-backed and zone-redundant (ZRS) snapshots cost more — reserve them for snapshots that genuinely need faster restore or zone durability.
Set and enforce a retention policy
Per stale snapshot removedAutomated snapshots with no cleanup accumulate indefinitely. Use a retention policy (or Azure Backup) that deletes old snapshots past the window your recovery needs actually require.
Clean up snapshots of deleted disks
Full storage of orphaned snapshotsSnapshots outlive the disks they came from. Reconcile snapshots against live disks and remove orphans still accruing storage.
FAQ
How is an Azure managed disk snapshot billed?
Per GB-month of snapshot storage — Standard LRS is ~$0.05/GB-month, so a 128 GB snapshot is ~$6.40/month (premium/ZRS cost more). Incremental snapshots store only changed blocks, so a series costs far less than size × count.
Are Azure snapshots incremental?
By default, yes — incremental snapshots store only the blocks changed since the previous snapshot of that disk. That makes frequent snapshots cheap; the cost grows from retention (un-pruned snapshot chains), not from each individual snapshot.
How does c3x estimate the cost?
From the snapshot's disk size at the snapshot rate. Multiply by retention to see accumulated cost; incremental snapshots in practice cost less than the per-snapshot full-size figure.
Related resources
Estimate this resource in your own Terraform
Free, open source, no API key. C3X parses your Terraform and shows line-item cost for every resource, including azurerm_snapshot.