What does downtime actually cost you?
Two quick calculators: how much money an outage burns while your site is down, and what those pretty 99.9% promises mean in real minutes.
Downtime cost calculator
Sales, subscriptions, leads: whatever your site brings in per month.
Napkin math, on purpose: it assumes your revenue arrives evenly around the clock. Your 2 a.m. is probably cheaper than your Black Friday.
Uptime to downtime converter
What providers promise, and what that little number allows them to break.
| Period | Allowed downtime |
|---|---|
| Per day | 1 min 26 s |
| Per week | 10 min 5 s |
| Per month | 43 min 50 s |
| Per year | 8 h 45 min 58 s |
100% uptime does not exist. Whoever promises it hasn't been woken up at 3 a.m. yet.
How the math works
The cost calculator turns your monthly revenue into an hourly rate by dividing it by 730.5, the hours in an average month. An outage's cost is that hourly rate multiplied by how long you were down.
The yearly projections multiply your hourly rate by the downtime each uptime level allows: 99% lets your site be down almost 88 hours a year, 99.9% about 8 hours and 46 minutes.
The converter is the same formula in reverse: allowed downtime = (100% minus the promised uptime) times the length of the period, using a 30.44-day average month. No industry averages, no invented statistics. Your numbers, your math.
Say your store makes 50,000 a month. That is about 68 an hour (50,000 divided by 730.5). A four hour outage on an average day costs about 274, and a full day about 1,643. Plug your own revenue into the calculator above and it does this arithmetic for you.
One honest caveat: the formula assumes every hour sells the same, and real stores have rush hours. If half your sales happen in a four hour evening window, an outage inside that window costs several times the hourly average, and one at 4 a.m. costs much less. Treat the result as a floor, not a ceiling: when you plan, round up.
Common questions
How much downtime is 99.9% uptime?
About 8 hours 46 minutes per year, or roughly 43 minutes per month. Sounds tiny until it lands in the middle of your product launch.
Is this calculator accurate for my business?
It's an honest estimate, not an invoice. It spreads your revenue evenly across every hour, and real traffic has peaks and valleys. Use your own numbers and treat the result as the order of magnitude, not the exact peso.
How do I make downtime cost less?
You can't prevent every outage, but you control how long one lasts before you know about it. A monitor that checks your site and alerts you immediately turns an afternoon of silent losses into a five-minute fix. OhSnap does exactly that, free for up to 5 sites.
How do you calculate the cost of downtime?
Divide your monthly revenue by 730.5, the hours in an average month, and you have your revenue per hour. Multiply that by the hours you were down. That is the whole formula: cost = (monthly revenue / 730.5) x hours down. This calculator does the same arithmetic, plus yearly projections for each uptime level.
What is the average cost of downtime?
Published averages come from surveys of large enterprises and land in the thousands of dollars per minute, which says very little about a store or a client site. We skip industry averages on purpose: your own revenue produces a number you can actually defend. If you need a benchmark for a report, use the per hour figure this calculator gives you.
What causes website downtime?
The usual suspects: hosting or server failures, an expired domain or misconfigured DNS, an expired SSL certificate, a deploy or plugin update gone wrong, and traffic spikes the server cannot absorb. Most of them are cheap to fix and expensive to not notice.
Does downtime affect SEO?
Brief, rare outages are usually harmless: Google retries and moves on. Extended or repeated downtime is another story, because pages that cannot be crawled can drop out of the index, and a slow recovery compounds the traffic loss. Count search rankings as one more thing an unnoticed outage quietly spends.
How do I find out my website is down before customers do?
With a monitor: a service that requests your site every few minutes from the outside and alerts you the moment it stops responding, then again when it recovers. The alert channel matters more than people think, because an email at 2 a.m. wakes nobody. That is why OhSnap includes SMS on the free plan.
Now you know the cost. Shrink it.
OhSnap tells you the moment your site goes down, before your customers do. Free for 5 monitors, alerts included.