A Service Level Agreement (SLA) is a contractual commitment to a minimum level of service availability. In hosting, this is expressed as an uptime percentage — but the number alone tells you very little without understanding how it’s measured and enforced.
What 99.9% Uptime Actually Means
99.9% uptime sounds impressive, but it allows for 43 minutes of downtime per month — or over 8 hours per year. 99.95% cuts that to 21 minutes per month. 99.99% allows just 4 minutes. The difference between these tiers is significant for revenue-generating sites. Understand the real cost of downtime.
How Uptime is Measured
How uptime is measured matters enormously. Some providers measure from their network edge, meaning your site could be down but their network is ‘up’. Others exclude scheduled maintenance windows. The most honest SLAs measure from external monitoring points and include all downtime regardless of cause.
SLA Enforcement and Credits
Enforcement is where most SLAs fall apart. A common structure offers service credits — typically 5-10% of your monthly fee for each hour of downtime. This means if your $50/month hosting goes down for an entire day, you might receive a $5 credit. That rarely compensates for lost revenue.
Frequently Asked Questions
What does 99.9% uptime mean for a WordPress hosting SLA?
99.9% uptime means a maximum of 8 hours and 45 minutes of downtime per year, or about 43 minutes per month. In practice, this allows for a few brief incidents spread across the year. The number alone does not tell you much without understanding: how downtime is measured (some hosts only count complete outages, not slow response or partial failures), what compensation is provided (credits vs refunds), whether you must file a claim or credits are automatic, and whether maintenance windows count toward downtime. Read the full SLA document rather than just the headline percentage.
What should a WordPress hosting SLA include?
A credible hosting SLA should specify: how uptime is measured (external monitoring from multiple locations is more credible than internal monitoring), what counts as downtime (complete unavailability only, or also degraded performance?), the compensation structure (automatic credits vs claim-required refunds, and the credit amount as a percentage of monthly fee), what is excluded from uptime calculations (scheduled maintenance, DDoS attacks, customer-caused issues), the measurement period (monthly vs annual calculation), and how to verify uptime history. SLAs that are difficult to understand or require complex claims processes are often designed to minimise payouts.
How do I verify a WordPress host’s actual uptime before signing up?
Ask the host for their uptime history dashboard or ask to see monitoring reports for existing customers. Use third-party monitoring tools (UptimeRobot, Pingdom, StatusPage.io) to monitor the host’s own website as a proxy indicator of infrastructure reliability. Check Trustpilot and Google reviews specifically for mentions of downtime or reliability issues — these are harder to fake than the host’s own published statistics. For agencies, ask potential host referees specifically about uptime experience rather than general satisfaction. A host confident in their reliability will share monitoring data without hesitation.
What is an acceptable uptime SLA for a business WordPress site?
99.9% (43 minutes downtime/month maximum) is the industry standard minimum for business sites. 99.95% (22 minutes/month) is better for sites with significant revenue impact. The SLA percentage matters less than the compensation terms and measurement methodology. A 99.99% SLA with complex claim requirements and minimal compensation is less valuable than a 99.9% SLA with automatic credits of meaningful value. For UK businesses with peak trading periods (Black Friday, seasonal promotions), also check whether the SLA treats all hours equally or excludes high-traffic periods from coverage.
What compensation should a WordPress host provide for downtime?
Standard compensation is service credits (extending your paid hosting period) calculated as a multiple of the downtime duration — typically 5-10x the hourly rate for affected downtime. For example, if your monthly fee is £45 (£0.0625/hour), a 4-hour outage might result in a £2.50 credit at 10x rate. This compensation rarely reflects actual business impact. More meaningful SLAs include higher credit multiples (20-50x), no claim requirement (credits are automatic), and separate guarantees for specific critical metrics like checkout availability. WP Pro Host provides automatic credits without requiring claim submission.