azure-cost-estimator

# Azure Cost Estimator Estimate monthly costs for Azure resources using the **Azure Retail Prices API** — a free, unauthenticated REST API that returns real Microsoft retail pricing. ## When to Use - During template generation (Stage 2) to show cost estimates before deployment - When user asks "how much will this cost?" or "estimate costs" - To compare cost of different SKU options - To validate budget constraints before deployment ## API Reference **Endpoint:** `https://prices.azure.com/api/retail/prices` **Key facts:** - No authentication required - OData `$filter` for targeted queries - Filter values are **case-sensitive** (e.g., `'Virtual Machines'` not `'virtual machines'`) - Returns max 1,000 records per page (use `NextPageLink` for pagination) - Currency defaults to USD; override with `currencyCode='EUR'` etc. - Always filter for `priceType eq 'Consumption'` and `isPrimaryMeterRegion eq true` unless looking for reservations **Filterable fields:** `armRegionName`, `serviceName`, `armSkuName`, `meterName`, `productName`, `skuName`, `serviceFamily`, `priceType` ## Procedure ### 1. Parse ARM Template Resources Extract from the ARM template: - Resource type (`Microsoft.Compute/virtualMachines`, `Microsoft.Storage/storageAccounts`, etc.) - SKU/size (e.g., `Standard_B1ls`, `Standard_LRS`) - Region (`armRegionName` value, e.g., `southeastasia`, `eastus`) - Any quantity-affecting properties (disk size, number of instances, reserved capacity) ### 2. Map Resource Types to Pricing API Queries Use the mapping table below to construct the correct API filter for each resource type. Run each query using `curl` in the terminal. **Query pattern:** ```bash curl -s "https://prices.azure.com/api/retail/prices?\$filter=<FILTER>" | python3 -c " import sys, json data = json.load(sys.stdin) for item in data.get('Items', []): print(f\"{item['meterName']:30s} {item['retailPrice']:>10.6f} {item['unitOfMeasure']:15s} {item['productName']}\") " ``` ### Resource Type Mapping #### Virtual Machines (`Microsoft.Compute/virtualMachines`) ``` serviceName eq 'Virtual Machines' and armRegionName eq '{region}' and armSkuName eq '{vmSize}' and priceType eq 'Consumption' and contains(productName, 'Linux') # or 'Windows' based on osProfile ``` Pick the result where `meterName` matches the SKU base name (e.g., `B1ls` for `Standard_B1ls`). **Unit:** `1 Hour` → multiply by **730** for monthly estimate. **OS detection from ARM template:** - `osProfile.linuxConfiguration` present → Linux - `osProfile.windowsConfiguration` present → Windows #### Managed Disks (`Microsoft.Compute/disks` or implicit VM OS disk) ``` serviceName eq 'Storage' and armRegionName eq '{region}' and meterName eq '{diskTier} LRS Disk' # e.g., 'P4 LRS Disk', 'S4 LRS Disk' and priceType eq 'Consumption' ``` **Disk tier mapping** (from `diskSizeGB` or `sku.name`): | ARM `sku.name` | Prefix | Sizes | |----------------|--------|-------| | Premium_LRS | P | P4 (32GB), P6 (64GB), P10 (128GB), P15 (256GB), P20 (512GB), P30 (1TB) | | StandardSSD_LRS | E | E4, E6, E10, E15, E20, E30 | | Standard_LRS | S | S4, S6, S10, S15, S20, S30 | If VM uses `osDisk.managedDisk.storageAccountType` → use that to determine the tier. **Unit:** `1/Month` → use directly. #### Storage Accounts (`Microsoft.Storage/storageAccounts`) ``` serviceName eq 'Storage' and armRegionName eq '{region}' and skuName eq '{redundancy}' # e.g., 'Standard LRS', 'Standard GRS' and meterName eq 'LRS Data Stored' # or 'GRS Data Stored' and productName eq 'Blob Storage' and priceType eq 'Consumption' ``` **Unit:** `1 GB/Month` → estimate based on expected storage. Use **10 GB** as default if unknown. Also add transaction costs: search for `meterName eq 'Write Operations'` (per 10,000 ops). #### Function Apps (`Microsoft.Web/sites` with `kind: functionapp`) **Consumption plan:** ``` serviceName eq 'Functions' and armRegionName eq '{region}' and priceType eq 'Consumption' ``` Key meters: - `Execution Time` — per GB-s ($0.000016/GB-s, first 400,000 GB-s/month free) - `Total Executions` — per execution ($0.20/million, first 1M/month free) **Dedicated plan:** Price the App Service Plan instead (see below). #### App Service Plans (`Microsoft.Web/serverfarms`) ``` serviceName eq 'Azure App Service' and armRegionName eq '{region}' and armSkuName eq '{skuName}' # e.g., 'B1', 'S1', 'P1v3' and priceType eq 'Consumption' ``` **Unit:** `1 Hour` → multiply by **730** for monthly. #### SQL Database (`Microsoft.Sql/servers/databases`) **DTU model:** ``` serviceName eq 'SQL Database' and armRegionName eq '{region}' and meterName eq '{tier} DTUs' # e.g., 'Basic DTUs', 'S1 DTUs' and priceType eq 'Consumption' ``` **vCore model:** ``` serviceName eq 'SQL Database' and armRegionName eq '{region}' and skuName eq '{tier}' and priceType eq 'Consumption' ``` #### Cosmos DB (`Microsoft.DocumentDB/databaseAccounts`) ``` serviceName eq 'Azure Cosmos DB' and armRegionName eq '{region}' and meterName eq '100 RU/s' # or 'Autoscale - 100 RU/s' and priceType eq 'Consumption' ``` **Unit:** `1 Hour` per 100 RU/s → multiply by **730** × (provisioned RU/s ÷ 100). Storage: search `meterName eq '1 GB Data Stored'`. #### Public IP (`Microsoft.Network/publicIPAddresses`) ``` serviceName eq 'Virtual Network' and armRegionName eq '{region}' and meterName eq 'Static Public IP' # or 'Dynamic Public IP' or 'Basic IPv4 Static Public IP Address' and priceType eq 'Consumption' ``` **Unit:** `1 Hour` → multiply by **730**. #### Application Insights (`Microsoft.Insights/components`) ``` serviceName eq 'Azure Monitor' and armRegionName eq '{region}' and meterName eq 'Data Ingestion' and priceType eq 'Consumption' ``` **Unit:** `1 GB` — first 5 GB/month free. Estimate **1 GB/month** for dev, **5-10 GB** for prod. #### Key Vault (`Microsoft.KeyVault/vaults`) ``` serviceName eq 'Key Vault' and armRegionName eq '{region}' and priceType eq 'Consumption' ``` Key meters: `Operations` (per 10,000), `Certificate Renewals`, `HSM Key Operations`. Typically **< $1/month** for dev workloads. #### Log Analytics Workspace (`Microsoft.OperationalInsights/workspaces`) ``` serviceName eq 'Azure Monitor' and armRegionName eq '{region}' and meterName eq 'Pay-as-you-go Data Ingestion' and priceType eq 'Consumption' ``` **Unit:** `1 GB` — first 5 GB/day free on pay-as-you-go tier. #### Network Security Group / Virtual Network / NIC These resources are **free** — no pricing API query needed. Note this in the output: ``` Network Security Group $0.00/month (no charge) Virtual Network $0.00/month (no charge) Network Interface $0.00/month (no charge) ``` ### 3. Query the API For each resource, run the constructed query. Use `curl` with proper URL encoding: ```bash curl -s "https://prices.azure.com/api/retail/prices?\$filter=serviceName%20eq%20%27Virtual%20Machines%27%20and%20armRegionName%20eq%20%27southeastasia%27%20and%20armSkuName%20eq%20%27Standard_B1ls%27%20and%20priceType%20eq%20%27Consumption%27" \ | python3 -c " import sys, json data = json.load(sys.stdin) for item in data.get('Items', []): if item.get('isPrimaryMeterRegion'): print(json.dumps({ 'meter': item['meterName'], 'price': item['retailPrice'], 'unit': item['unitOfMeasure'], 'product': item['productName'], 'sku': item.get('armSkuName', ''), 'type': item['type'] }, indent=2)) " ``` ### 4. Calculate Monthly Costs Apply the correct multiplier based on `unitOfMeasure`: | Unit | Monthly Multiplier | Notes | |------|-------------------|-------| | `1 Hour` | × 730 | 365.25 days × 24 hours ÷ 12 months | | `1 GB/Month` | × estimated GB | Use actual or default estimate | | `1/Month` | × 1 | Already monthly | | `100/Month` | × quantity ÷ 100 | Per 100 units/month | | `1 GB` | × estimated GB | Ingestion-based | | `10K` | × estimated ops ÷ 10000 | Transaction-based | ### 5. Handle Free Tiers and Included Quantities Note any free tier allowances in the output: | Service | Free Allowance | |---------|---------------| | Functions (Consumption) | 1M executions + 400K GB-s/month | | Application Insights | 5 GB ingestion/month | | Log Analytics | 5 GB/day ingestion | | Cosmos DB (Serverless) | No minimum, pay per RU | | Bandwidth | First 5 GB outbound/month | If the estimated usage falls within the free tier, show `$0.00` with a note. ### 6. Present Cost Estimate Format the output as a clear cost breakdown: ```markdown ### 💰 Estimated Monthly Cost | # | Resource | SKU/Tier | Meter | Unit Price | Monthly Est. | |---|----------|----------|-------|-----------|-------------| | 1 | vm-linuxvm-dev-sea | Standard_B1ls | B1ls (Linux) | $0.0052/hr | $3.80 | | 2 | OS Disk (30GB) | Standard_LRS | S4 LRS Disk | $1.54/mo | $1.54 | | 3 | pip-linuxvm-dev-sea | Basic Static | Static IP | $0.0036/hr | $2.63 | | 4 | NSG, VNet, NIC | — | — | — | $0.00 | | | | | | **Total** | **$7.97/mo** | **Notes:** - Prices are Microsoft retail (pay-as-you-go) in USD - Actual costs may vary with reserved instances, savings plans, or enterprise agreements - Bandwidth egress is not included (first 5 GB/month free) - Prices retrieved from [Azure Retail Prices API](https://learn.microsoft.com/en-us/rest/api/cost-management/retail-prices/azure-retail-prices) on {date} **Cost optimization options:** - 💡 1-Year Reserved Instance: ~{X}% savings - 💡 3-Year Reserved Instance: ~{Y}% savings - 💡 Spot Instance: ~{Z}% savings (interruptible) ``` ### 7. Save Cost Estimate Save the estimate to the deployment artifacts: **File:** `.azure/deployments/{deployment-id}/cost-estimate.json` ```json { "estimatedAt": "2026-02-19T10:00:00Z", "currency": "USD", "region": "southeastasia", "monthlyTotal": 7.97, "resources": [ { "name": "vm-linuxvm-dev-southeastasia", "type": "Microsoft.Compute/virtualMachines", "sku": "Standard_B1ls", "meter": "B1ls", "unitPrice": 0.0052, "unitOfMeasure": "1 Hour", "monthlyEstimate": 3.80 } ], "notes": [ "Retail pay-as-you-go pricing", "Bandwidth egress not included" ], "source": "Azure Retail Prices API", "sourceUrl": "https://prices.azure.com/api/retail/prices" } ``` ## Error Handling **If a price is not found for a resource:**