AWS costs can creep up faster than expected, especially when you’re still learning which services you’re actually using. Budgets and alarms are the mechanism that catches it early — before a surprise shows up at the end of the billing cycle.
This covers how to set a cost budget and attach an alarm to it.
Why This Matters
Without budgets, the only signal you get is the monthly invoice. With budgets, you get notified when spend hits a threshold you defined — at 80%, at 100%, or at any custom amount. That’s the difference between catching a runaway cost during the month versus discovering it after.
For learners and small teams especially, a single misconfigured service left running can erase a month of budget in hours. The alarm doesn’t prevent it — but it tells you early enough to respond.
Step 1: Create a Budget
Navigate to the AWS Management Console and open Billing and Cost Management. From the left menu, select Budgets, then create a new budget.
Configure:
- Budget type: Cost (tracks actual spend against a dollar amount)
- Amount: the monthly limit you want to track
- Period: monthly
- Budget filters: optionally scope to specific services, regions, or tags
For example, a $10/month budget scoped to all services gives you visibility across the full account.
Step 2: Create a Budget Alarm
After creating the budget, add an alert threshold.
Configure:
- Threshold type: percentage of budgeted amount (e.g., 80%)
- Notification channel: email address to receive alerts
With this in place, AWS sends an email when actual spend reaches 80% of your budget. You can add multiple thresholds — 50%, 80%, 100% — to get progressively escalating signals.
Advanced: Alarm Actions
Budget alarms can also trigger automated actions when a threshold is crossed. Options include:
- Applying an IAM policy that restricts future spending
- Targeting EC2 instances or Auto Scaling groups
Automated actions are useful if you want the system to self-limit, not just notify. For most learning setups, email notification is enough — the goal is awareness, not automation.
Key Points
- Budgets are forward-looking: they track spend against a target, not just report history
- Set a budget when you first create an AWS account — before you deploy anything
- Alerts go to email by default; also connect SNS for Slack or PagerDuty integration
- Review your budget filters periodically — new services you spin up may fall outside the scope of existing filters
- AWS Free Tier usage is separate from billing budgets — add a Free Tier alert in the Billing console to catch Free Tier overruns independently