📶 Server Uptime / SLA Calculator

Service Level Agreements express reliability as a percentage — 99.9%, 99.99%, and so on — but percentages are hard to reason about intuitively. This calculator translates any SLA percentage into concrete allowed downtime (in hours, minutes, and seconds per day, month, and year), compares it against your actual measured uptime, flags whether the SLA was breached, and estimates the financial credit a provider would typically owe you under common tiered-credit contract structures.

How It Works

Choose your promised SLA tier from the dropdown (99%, 99.5%, 99.9%, 99.95%, 99.99%, or 99.999%), enter the actual uptime percentage you measured over the billing period, and enter your monthly bill amount. The calculator computes allowed downtime at the promised SLA by subtracting the SLA fraction from 100% and multiplying by the total seconds in a day, month (30 days), and year, then does the same for your actual measured uptime. It compares actual downtime to allowed downtime to determine breach status, and applies an illustrative tiered credit schedule — 10% credit if actual uptime is below the SLA but at or above 99%, 25% if between 95% and 99%, and 100% if below 95% — multiplied against your monthly bill to estimate the credit owed.

Why It Matters

A single percentage point of uptime can represent a difference of hours per month in real downtime, and most SLA contracts pay compensation only in service credits — not cash — often capped and only issued if the customer proactively files a claim within a specific window. Understanding exactly how much downtime your SLA promises, how far your actual measured uptime fell short, and what credit you're contractually owed helps you hold providers accountable and negotiate better terms, whether you're a customer of a cloud provider or the one offering an SLA to your own customers.

Tips for Accurate Results

• Always confirm your specific provider's credit tiers and thresholds in their SLA document — the 10%/25%/100% schedule here is illustrative, not universal, and real contracts vary widely in structure and caps.
• Measure uptime the same way your provider does — many SLAs exclude scheduled maintenance windows or define "down" only above a specific error-rate threshold, which can differ from your own monitoring.
• Most SLA credits must be claimed within a specific window (often 30 days) after the incident — check your contract's claim procedure, since credits are rarely applied automatically.
• Remember that credits are typically capped (often at 100% of that period's bill) and paid as service credit toward future bills, not a cash refund.
• Use the downtime comparison table to understand what tier you'd actually need to negotiate for if your application requires a specific maximum downtime budget.