Nines
The SRE's Essential SLA Calculator
Available for iPhone and iPad • Also accessible on the web
Calculate SLAs with Confidence
Nines helps SREs and DevOps engineers instantly translate uptime percentages into actual downtime allowances. Set realistic availability targets and understand the practical impact of your SLA commitments.
Instant Calculations
Convert any uptime percentage to days, hours, minutes, and seconds across yearly, monthly, weekly, and daily timeframes.
Common SLA Targets
Quick access to industry-standard availability levels: 99.9%, 99.99%, 99.999%, and more. Compare targets instantly.
Native iOS Experience
Beautiful, fast, and optimised for iPhone and iPad. Calculate SLAs on the go, during incidents, or in planning sessions.
Zero Complexity
No spreadsheets, no formulas, no confusion. Just enter your target percentage and get clear, actionable results.
Privacy First
No data collection, no tracking, no accounts required. All calculations happen locally on your device.
Industry Standard
Based on calculations used by leading tech companies and cloud providers. Accurate and reliable every time.
Built by SREs, for SREs
Nines was created to solve a real problem that SRE and DevOps engineers face daily: understanding what uptime percentages actually mean in practice. When stakeholders ask for "five nines" of availability, do they understand that allows only 5 minutes of downtime per year?
Whether you're negotiating SLAs with vendors, setting internal service level objectives, or explaining availability trade-offs to leadership, Nines gives you instant clarity. Calculate the real-world impact of different availability targets and make informed decisions about redundancy, failover strategies, and incident response priorities.
The app includes both the mobile experience for on-the-go calculations and a web version for desktop use. Both are completely free, with no advertisements, no sign-ups, and no data collection.
Use Cases for Nines
How SRE teams use Nines in their daily work
Vendor SLA Evaluation
Quickly assess if a vendor's uptime commitment meets your needs. Calculate how their downtime allowance affects your own availability targets.
Internal SLO Setting
Set realistic service level objectives for your team. Understand the operational cost of different availability levels before committing.
Incident Response Planning
Calculate your remaining error budget during an outage. Know exactly how much downtime you have left before breaching your SLA.
Stakeholder Communication
Translate technical availability metrics into terms business stakeholders understand. Show the real impact of different SLA commitments.
Architecture Decision-Making
Justify investments in redundancy and failover systems by showing the availability improvements they provide.
Contract Negotiations
Have concrete numbers at hand when negotiating service agreements. Know what different SLA levels actually mean in practice.
Capacity Planning
Factor in maintenance windows and planned downtime when setting availability targets. Ensure your SLAs account for operational reality.
Training and Education
Help junior engineers and new team members understand the practical implications of different availability targets.
Ready to Calculate with Confidence?
Download Nines for iPhone or use the web calculator to start understanding your SLAs today.