SLA Downtime Calculator – Allowed Downtime per SLA

Calculate allowed downtime per year, month, and week for any SLA percentage.

About This Calculator

Calculate allowed downtime per year, month, and week for any SLA percentage. Use the calculator above for instant results.

Worked Examples

Example 1: 99.9% SLA (3 nines)

  • Year: 526 min (8.77 hrs) | Month: 43.8 min | Week: 10.1 min
  • Day: 86.4 seconds

Answer: 8.77 hrs/year

Example 2: 99.99% (4 nines)

  • Year: 52.6 min | Month: 4.38 min | Day: 8.64 seconds

Answer: 52.6 min/year

Example 3: 99.5% (common basic SLA)

  • Year: 43.8 hrs | Month: 3.65 hrs | Week: 50.4 min

Answer: 43.8 hrs/year

Who Uses This Calculator?

💻
SREs

Calculate SLA budget.

📊
IT Managers

Set and report on SLAs.

🔧
DevOps

Error budget management.

💾
Cloud Architects

SLA-driven architecture design.

Common Mistakes to Avoid

❌ SLA is not the same as error budget

Error budget = 100% - SLA%. Spend it wisely on deployments and maintenance. Track burn rate.

❌ Cascading SLAs

A service dependent on 3 components each at 99.9% SLA is only 99.7% available (0.999³).

Frequently Asked Questions

Error budget concept?

If your SLA is 99.9%, you have 0.1% error budget per month (43.8 minutes). Use it for deployments. If burned, freeze releases.

SLA vs SLO vs SLI?

SLI: actual measurement (latency p99). SLO: target (p99 < 200ms). SLA: contract with penalties. SLIs are measured, SLOs are targets, SLAs are commitments.

Typical cloud SLAs?

Storage: 99.9-99.999%. Compute: 99.9-99.99%. Managed databases: 99.9-99.999%. Always check the fine print on what qualifies as downtime.