Estimate Web Application Firewall costs for AWS WAF, Cloudflare, or Azure WAF. Calculate ACL, rule, and request-based pricing for your web traffic.
A Web Application Firewall (WAF) protects your applications from common web exploits like SQL injection, cross-site scripting (XSS), and bot attacks. Cloud WAFs have replaced traditional hardware appliances, but pricing varies significantly between providers.
AWS WAF charges per Web ACL ($5/month), per rule ($1/month), and per million requests ($0.60). A typical setup with one ACL, 10 managed rules, and 50 million requests costs roughly $45/month. Cloudflare includes WAF in Pro ($20/mo) and Business ($200/mo) plans. Azure WAF charges per gateway hour plus per-rule charges.
This calculator helps you estimate the monthly cost of a cloud WAF deployment based on the number of ACLs, rules, and request volume. Use it to compare providers and understand how request volume impacts your security budget.
Precise measurement of this value supports informed infrastructure decisions and helps engineering teams optimize system architecture for both performance and cost efficiency. Quantifying this parameter enables systematic comparison across environments, deployments, and time periods, revealing optimization opportunities that improve both performance and cost-effectiveness.
WAF costs scale with request volume, which can make budgeting unpredictable for high-traffic applications. Understanding the three-part pricing model (ACL + rules + requests) helps you optimize by consolidating ACLs, using managed rule groups efficiently, and pre-filtering bot traffic before it reaches the WAF. Regular monitoring of this value helps DevOps teams detect anomalies early and maintain the system reliability and performance that users and business stakeholders expect.
ACL Cost = ACL_count × acl_fee Rule Cost = rules × rule_fee Request Cost = requests_millions × per_million_rate Total Monthly = ACL Cost + Rule Cost + Request Cost
Result: $85.00/month
Two Web ACLs at $5/month: $10. 15 rules at $1/month: $15. 100 million requests at $0.60/million: $60. Total: $85/month. This covers a production and staging environment with AWS Managed Rules and custom rate-limiting rules.
AWS WAF: pay-per-use ($5/ACL + $1/rule + $0.60/M requests). Best for AWS-native apps. Cloudflare: flat-rate ($20 Pro, $200 Business). Best for cost-predictable, high-traffic sites. Azure WAF (Application Gateway): per-gateway-hour (~$0.246/hr) + per-rule charges. Best for Azure-deployed apps. Each has trade-offs in flexibility, rule customization, and integration.
The biggest cost driver is request volume. Reduce it by: implementing bot detection at the CDN edge (before WAF), using Cloudflare Bot Management or AWS Bot Control, caching static assets to avoid WAF evaluation, and setting up geo-blocking for regions you don't serve.
Start with AWS Managed Rules Core Rule Set and Known Bad Inputs. Add SQL Injection and XSS rules for database-backed apps. Use rate-based rules ($1/mo) to throttle abusive IPs. Custom rules for business logic protection (e.g., blocking specific user agents or request patterns) should be added incrementally based on observed attack patterns.
AWS WAF charges $5/month per Web ACL, $1/month per rule or rule group, and $0.60 per million requests. A typical small deployment costs $15–40/month. High-traffic sites (1B+ requests/month) pay $600+ in request fees alone.
For high-traffic sites, often yes. Cloudflare Pro ($20/mo) includes WAF with unlimited requests, while AWS WAF charges per request. For a site with 200M requests/month, AWS WAF costs ~$135/mo (1 ACL, 10 rules, 200M requests) vs Cloudflare's flat $20/mo.
Managed rule groups are pre-built sets of WAF rules maintained by AWS or third-party vendors. The AWS Core Rule Set covers OWASP Top 10 vulnerabilities. Each managed rule group counts as one rule for billing ($1/mo) even though it may contain dozens of individual rules.
If you handle user data, payment information, or have any authentication system, yes. A WAF blocks common attacks that even secure code cannot prevent (zero-day exploits, bot scraping, credential stuffing). It is also often required for PCI DSS, HIPAA, and SOC 2 compliance.
Modern cloud WAFs add 1–5ms of latency per request for rule evaluation. This is negligible for most applications. Complex regex-based custom rules may add slightly more. Managed rule groups are optimized for minimal latency impact.
A WAF can mitigate application-layer (Layer 7) DDoS attacks through rate limiting and bot detection. However, it does not protect against volumetric (Layer 3/4) attacks. For comprehensive DDoS protection, combine WAF with AWS Shield, Cloudflare, or a dedicated DDoS mitigation service.