Every host advertises an uptime percentage. Almost nobody explains what the number means in hours, or what those hours cost you. Here is both.
The maths, in plain hours
Uptime percentages compress badly. The difference between 99% and 99.9% sounds like rounding. In practice it's the difference between three and a half days offline a year and under nine hours.
| Uptime | Per month | Per year |
|---|---|---|
| 99% | 7 hours 18 min | 3 days 15 hours |
| 99.5% | 3 hours 39 min | 1 day 19 hours |
| 99.9% | 43 minutes | 8 hours 45 min |
| 99.99% | 4 minutes | 52 minutes |
So "99% uptime", which sounds perfectly respectable in a sales page, permits your site to be down for most of a working week every year. If that happens to land on your busiest trading day, the percentage is no comfort at all.
What downtime actually costs
Work it out for your own business rather than trusting a generic figure. Take your monthly revenue that originates online, enquiries as well as direct sales, and divide by the hours you actually trade.
A business turning over R150 000 a month, trading 200 hours a month, is making roughly R750 an hour. Nine hours of downtime is about R6 750 in directly lost trade. That's before the second-order costs, which are usually larger:
- Lost trust. Someone who finds your site down at the moment they were ready to buy generally goes to a competitor and doesn't come back to check.
- Search impact. Repeated or prolonged outages when Google crawls can affect how your pages are treated.
- Your time. The hours spent chasing support and reassuring customers don't appear on any invoice, but they're real.
Uptime isn't the only number
A server can be up and still be useless. Two other measures matter at least as much, and are quoted far less often:
Time to first byte
How long the server takes to start responding. Under 200ms is good; over 600ms means visitors feel the lag before anything renders. This is where hosting location matters: if your customers are in South Africa and your server is in Europe, every request pays that round trip.
Time to recovery
The one nobody advertises. When something does break, how long until it's fixed? A host with 99.9% uptime that takes six hours to answer a ticket is worse to live with than one at 99.5% that responds in ten minutes.
Ask a prospective host what their average first-response time is. The ones who are proud of it will tell you immediately.
How to check your current host
- Set up independent monitoring. Free services will check your site every few minutes and email you when it stops responding. Don't rely on your host's own status page.
- Test speed from South Africa. A site that tests fast from a European server may still be slow for your actual customers.
- Send a test support request. Time the reply. Do it on a Friday afternoon, not a Tuesday morning.
- Confirm your backups exist. Ask for a restore. A backup nobody has ever tested is a hope, not a backup.
- Check who owns the domain. Look up the registrant. It should be you.
What we do
We host on South African infrastructure with monitoring that alerts us before most clients notice a problem, daily backups kept for thirty days, and free SSL that renews itself. Because we build sites as well as host them, there's never an argument about whose fault something is.
Migration is free and usually causes no downtime at all, we copy everything across and test it fully before changing a single DNS record. More on our hosting, or ask us to look at your current setup.