tool · conversion · loss model
Updated May 12, 2026
A spam filter that blocks bots but also blocks impatient humans is still expensive. Estimate the hidden cost before adding a puzzle to every form submission.
inputs
estimated monthly loss
$3,600Real revenue lost to a CAPTCHA every month — money that never reaches your funnel.
Keep the form easy for real visitors. Score the submitted text after the user clicks submit, then block, queue, or deliver based on risk.
See the CAPTCHA alternative patternPublished research and field A/B tests put reCAPTCHA v2 image-puzzle drop-off between 5% and 15% of attempted submissions, and invisible challenges between 1% and 4%. Multiply that drop-off by your form-start rate and lead value to get the monthly hidden cost.
It depends on which version and how it's configured. Visible v2 image puzzles consistently hurt conversion. v3 score-based challenges and hCaptcha invisible mode are gentler but still measurable. The friction calculator lets you estimate the cost for your specific volume.
Server-side text classification (like Siftfy) catches the same content-bots that CAPTCHAs target, without asking users to do anything. Combine it with a honeypot field and IP rate limits for a layered defense that's invisible to legitimate visitors.
Yes — keep CAPTCHA as a fallback you can switch on for the duration of an active abuse campaign, then switch off. Permanent CAPTCHA on every form charges legitimate users for a problem that only flares occasionally.