What 99.9% Uptime Allows
A 99.9% uptime SLA allows roughly 526 minutes of downtime per year — about eight hours and 46 minutes. The number sounds impressive until you do the arithmetic. The calculator on this page converts any uptime percentage into minutes and hours of allowed downtime per month and year so you can judge whether the guarantee is meaningful.
Total over
That is a month on average, against an intro price of .
- Year 1the year the advert is about
- Three years
- Five years
- The intro price is this much of the total of billed at the promo rate
- Renewal price, as a multiple
Year 2 costs more than year 1. That is the renewal, not a price rise — it was in the terms when you signed up.
Totals assume the renewal price holds and no plan change. Hosts do raise renewal prices between terms, so treat this as the floor of what the years ahead cost, not a quote.
Effective monthly
Monthly jump at renewal
Hosting, over the term
Domain + mailboxes
Year by year
| Year | Hosting | Domain | Mailboxes | Year total | Running total |
|---|
Swipe the table sideways to see every column.
The Arithmetic Behind Uptime Claims
Uptime is expressed as a percentage of total minutes in a year. A standard year has 525,960 minutes (365.25 days multiplied by 1,440 minutes per day). Multiply the downtime fraction by that total to get your allowed outage window.
| SLA | Downtime allowed / year | Downtime allowed / month |
|---|---|---|
| 99.5% | ~2,630 min (43 h 50 min) | ~219 min (3 h 39 min) |
| 99.9% | ~526 min (8 h 46 min) | ~44 min |
| 99.95% | ~263 min (4 h 23 min) | ~22 min |
| 99.99% | ~53 min | ~4 min 23 sec |
The jump from 99.9% to 99.99% is a tenfold reduction in allowed downtime. That single extra nine represents the difference between a host that can be down for an entire workday and one that must recover within an hour across the whole year.
What SLA Credits Actually Cover
Most SLA guarantees are backed by service credits, not refunds. If your host breaches its uptime commitment, you typically receive a percentage of that month's fee as a credit toward future invoices — not cash back, not compensation for lost revenue. The credit usually caps at one month's hosting fee regardless of how long the outage lasted.
Claiming a credit often requires you to open a support ticket within a specific window (commonly 30 days) and provide evidence of the outage. Scheduled maintenance windows, force majeure events, and problems caused by your own configuration are excluded from most SLA calculations. Read the fine print before assuming the percentage on the sales page reflects real accountability.
The calculator on this page lets you enter your monthly cost alongside the SLA percentage. It shows the maximum credit you could claim for a breach, which puts the guarantee in concrete financial terms rather than abstract nines.
Uptime is measured from the host's perspective. Your site can still be unreachable due to DNS issues, CDN failures, or application errors that fall outside the hosting SLA entirely.
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Related guides and tools
Sources
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All figures are pure arithmetic from the minutes-per-year base (365.25 x 1,440 = 525,960). No vendor-specific SLA terms cited.
- Every figure in the calculators on this site is typed in by you. No price, allowance or renewal rate is stored in the page.