Check what a website SLA guarantees and the credits a breach earns.
An uptime commitment is really a downtime allowance: 99.9% of a 30-day month permits about 43 minutes of outage, while 99.99% permits only four. Comparing recorded downtime against that allowance shows whether the SLA was breached, and service credits are normally calculated per breached hour as a percentage of the monthly fee, capped at the fee itself. Credits are compensation for the contract, not for the business impact.
Downtime allowance and service credit
Allowed downtime = 43,200 min x (1 - committed uptime/100); credit = monthly fee x credit rate x breached hours, capped at the fee
Service level agreements are contracts with specific definitions of availability, exclusions and claim procedures, including deadlines for requesting credits. This is an arithmetic aid only and is not legal advice — read the agreement itself.
About 43 minutes a month, or 8.8 hours a year. Each additional nine cuts that by a factor of ten — 99.99% allows roughly 4.3 minutes a month.
As a percentage of the monthly fee per breached period, escalating with severity and capped at the full monthly fee. They almost never reflect the revenue actually lost.
Usually not — most agreements exclude announced maintenance windows, which is why measured availability often looks worse than the contractual figure.