SLA & Uptime Calculator
Calculate downtime allowance, check SLA compliance, and estimate revenue impact — instantly.
SLA Target
Monthly Revenue (optional)
Used to calculate revenue lost per minute of downtime
▸ Downtime Allowance
- Per year
- 8h 45m 58s
- Per month
- 43m 50s
- Per week
- 10m 5s
- Per day
- 1m 26s
▸ Breach Checker
Total downtime this billing period
✓ Within SLA
0s used of 43m 50s allowed this month
0% of monthly budget used
▸ Revenue Impact
Enter monthly revenue above to see impact estimates.
SLA Tier Reference Table
| SLA | Yearly | Monthly | Weekly | Daily |
|---|---|---|---|---|
| 99% | 3d 15h 39m 36s | 7h 18m 18s | 1h 40m 48s | 14m 24s |
| 99.9% ◀ | 8h 45m 58s | 43m 50s | 10m 5s | 1m 26s |
| 99.95% | 4h 22m 59s | 21m 55s | 5m 2s | 43s |
| 99.99% | 52m 36s | 4m 23s | 1m 0s | 9s |
| 99.999% | 5m 16s | 26s | 6s | 1s |
What is an SLA uptime guarantee?
A Service Level Agreement (SLA) is a contractual commitment from a provider — cloud, hosting, or SaaS — specifying the minimum percentage of time their service will be operational. An SLA of 99.9% does not mean the service is always up; it means the provider guarantees no more than 0.1% downtime per period. Exceed that allowance and you are typically owed service credits.
SLA percentages are expressed as a fraction of total time. A 99.9% monthly SLA allows roughly 43 minutes and 49 seconds of downtime per month. A 99.99% SLA tightens that to about 4 minutes and 21 seconds. The difference sounds small on paper but has major operational implications — and a major impact on cost.
Understanding the nines: 99% vs 99.9% vs 99.99% vs 99.999%
SLA tiers are commonly described by their number of nines. Each additional nine reduces allowed downtime by roughly a factor of ten — but the engineering effort and cost to achieve it often grows exponentially.
Up to 87h 36m downtime per year. Common for non-critical internal tools and early-stage services. Not suitable for customer-facing production systems.
Up to 8h 45m downtime per year. The most common tier for managed hosting and cloud VMs. Achievable with a single redundant server and basic monitoring.
Up to 52m 35s per year. Requires active-active redundancy, automated failover, and no single point of failure. Typical for enterprise cloud services and financial platforms.
Up to 5m 15s per year. The gold standard for telecommunications and critical infrastructure. Requires multiple geographic regions, automated recovery, and continuous chaos testing.
What happens when an SLA is breached?
When a provider's uptime falls below their SLA commitment, most contracts entitle you to service credits — a percentage of your monthly bill applied against future invoices. Credits rarely cover the full business impact of an outage, which is why understanding your actual revenue exposure matters more than the credit amount.
How to calculate the real cost of downtime
Downtime costs more than most teams realize. The direct revenue loss from a sales-generating service going offline is just the start. Add engineering time to respond, customer support load, potential SLA penalties you owe your own customers, and long-term reputational damage, and the real figure can be five to ten times the raw revenue loss alone.
- • Lost revenue from transactions that could not complete
- • SLA credits you owe your own customers
- • Idle infrastructure still being billed during the outage
- • On-call and incident response overtime
- • Customer churn from lost trust after repeated incidents
- • Damage to brand reputation and negative reviews
- • Engineering time diverted from product to firefighting
- • Post-incident review and remediation work
Tip: Enter your monthly revenue in the calculator above to see per-minute and per-hour loss rates. Even a single hour at a low SLA tier can cost more than upgrading to a higher-reliability provider for an entire year.