“99.9% uptime” sounds nearly perfect until you convert it into actual hours a year and multiply by what your site earns per minute.
Free hosting tool
Website Downtime Cost Calculator
What one outage actually costs, or your projected annual cost from your host's uptime guarantee.
Runs entirely in your browser. Nothing you enter about your revenue is sent anywhere.
What this doesn't try to price
This calculator only counts revenue missed while the site was actually unreachable, a concrete, calculable number. It deliberately leaves out reputation damage, customers who try once during an outage and never come back, and any SEO impact from repeated downtime, all real, all genuinely costly, none of them honestly reducible to a formula. Treat the number here as a floor on the real cost of downtime, not the ceiling.
Downtime cost calculator FAQ
How is the cost of downtime actually calculated?
Your revenue is converted to a per-minute rate, multiplied by how much of it genuinely depends on the website being reachable, then multiplied by how many minutes it was down. A store doing €30,000 a month with 100% of sales online loses roughly €0.69 for every minute the site is unreachable, a blog monetized mostly through email and social loses far less per minute since most of its value doesn't evaporate the moment the site is briefly down.
What percentage should I use for "revenue dependent on the website"?
For a pure online store, close to 100%, no site, no checkout, no sales. For a lead-generation or content site monetized by ads or affiliate links, lower, visitors can't click an ad on a page that won't load, but the business doesn't stop entirely either. For a site that's mostly a brochure backing an offline business, lower still, most real revenue isn't happening on the page at that exact moment.
What do "the nines" (99.9%, 99.99%) actually mean in real downtime?
Each additional 9 cuts allowed downtime by roughly 10x. 99% uptime allows about 3.65 days of downtime a year, 99.9% allows about 8.76 hours, 99.99% allows about 52.6 minutes, and 99.999% allows about 5.3 minutes. The jump from "two nines" to "three nines" sounds small on paper and is enormous in practice, the reference table above shows the full comparison.
Does this include reputation damage or customers who never come back?
No, deliberately. Lost trust, a customer who tries once during an outage and never returns, or a search ranking dip from repeated downtime are all real costs, but they're speculative and vary hugely by business, there's no honest formula for them. This calculator sticks to the concrete, calculable number: revenue missed while the site was actually down. Treat it as a floor on the real cost, not the whole picture.
Is my data private?
Yes. Every calculation runs in your browser. Nothing you enter about your revenue is sent to a server.
Free downtime cost calculator by ANUPRESS
Why “per minute” is the right unit
Nobody thinks in per-minute revenue naturally, but it’s the only unit that makes an outage’s cost concrete. €30,000 a month sounds abstract; €0.68 a minute is exactly what disappears for every minute the site can’t take an order. Once revenue is converted to that rate, a two-and-a-half-hour outage stops being a vague inconvenience and becomes a specific number you can weigh against the cost of better hosting, a status-page monitor, or a faster on-call response.
The jump between “nines” is bigger than it sounds
99% and 99.9% look almost identical written down, one extra 9, but 99% allows 3.65 days of downtime a year while 99.9% allows only 8.77 hours, a roughly 10x difference for what reads like a rounding change. Each additional nine cuts allowed downtime by another factor of ten, which is exactly why hosts market “four nines” and “five nines” as meaningfully premium tiers rather than trivial upgrades, the practical difference for a business that actually depends on uptime is real money, not just a marketing number.
A number with an honest ceiling
This calculator only prices what’s directly measurable: revenue missed for exactly as long as the site was down. It doesn’t attempt to price a customer who tried once during an outage and quietly went to a competitor instead, or a temporary dip in search rankings after repeated downtime, both are real costs, and both vary too much by business to fake a formula for. Use the number here as the floor of what an outage costs, the honest minimum, not the full picture.