Website Bot Attack Cost Calculator.

Enter your own numbers and see what bots cost your website: the form spam and bot traffic you get every month, and what a single attack costs, next to the price of bot protection.

Website Bot Attack Cost Calculator

Your numbers: every month and one attack

Runs entirely in your browser

Based on

Team hour (€)

Developer hour (€)

New customers a day

Value of a customer (€)

Bots you deal with every month

Spam messages a month

Only if they apply to your site

Your site takes orders

Your site takes bookings or reservations

Your site has a sign-up or newsletter form

Your site offers vouchers or free trials

Your site sends SMS codes

Your site uses a service billed per request

Every month

One attack

Over a year, with one attack

Where the money goes · Every month

Form spam
Bot traffic (estimate)
Fake orders
Fake bookings
Fake sign-ups
Voucher and trial abuse
Text message abuse
Paid requests

Bot traffic is an estimate: bad bots make up about 37% of all web traffic (Imperva, 2025). We add them to about 50 visits per new customer, 3 pages each, at about €0.08 per 1,000 page loads.

Compared with bot protection

Verifications you need a month 10,000

Plans with bot detection start with Solo.

See all plans

Pure math, computed on your device. Nothing is transmitted or stored.

Where the starting numbers come from

They describe a typical business website with a contact form that wins 20 new customers on a normal day, each worth €150, with team time at €45 an hour. Every month it gets 300 spam messages; a Nucleus Research survey found that spotting and deleting one takes about 16 seconds. Bot traffic is estimated from your customers, because bad bots make up about 37% of all web traffic (Imperva Bad Bot Report 2025). One attack takes the site down or makes it too slow for 4 hours, so the customers you would win in those hours, about 3, go elsewhere. Replace every number with your own; our article The true cost of not using a CAPTCHA walks through a bigger example.

Why bots cost you customers

Bots rarely steal a customer directly. They crowd them out: during an attack a flood of requests slows the site down or takes it offline, and anyone who wants to buy, book or ask in that time goes elsewhere. The calculator spreads your daily customers over 24 hours and counts the ones that fall into the attack. Each lost customer costs what that customer would have been worth.

When an attack goes further

Taken-over accounts have to be reset and their owners told. Exposed personal data is a data breach: under the GDPR it may have to be reported to the authority within 72 hours, which takes time and usually legal advice. Locked data or broken systems need developers. The switches add example amounts for these cases; adjust the hourly costs to fit your team.

How to bring the number down

Stop the bots before they reach the form. TrustCaptcha checks every request in the background with proof-of-work, a bot score, a honeypot and your own security rules, without a puzzle for real visitors and without cookies. No protection stops every attack, so read the comparison as what is at stake, not as a promise.

Frequently asked questions

How much does a bot attack cost a website?

It depends on what the bots target. With the starting numbers on this page, everyday spam and bot traffic cost about €66 a month, and one attack that takes the site down for 4 hours costs about €690. If accounts are taken over or personal data is exposed, the bill quickly reaches several thousand euros.

What counts as a bot attack on a website?

Any automated traffic that abuses your forms or accounts: form spam, fake sign-ups, credential stuffing on the login, card testing at checkout, fake orders and bookings, and text message abuse through sign-up or password-reset forms.

Which costs does the calculator include?

Two kinds. Every month: the time spent sorting spam, the estimated cost of bot traffic and, if they apply to your site, fake orders, bookings and sign-ups, voucher and trial abuse, text message abuse and paid requests. For one attack: the customers lost while the site is down or slow, estimated extra hosting, the time someone spends fighting it, and the switches for support, clean-up, taken-over accounts, a data breach, locked data or broken systems.

How do I reduce the cost of bot attacks?

Check requests before they reach your forms. A CAPTCHA that verifies in the background, such as TrustCaptcha, stops most automated requests without slowing down real visitors.

Does the calculator send my numbers anywhere?

No. Everything is calculated in your browser, and nothing is transmitted or stored.

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