We started building this because every other baby calculator online looks like it was made in 2008, hides the math, and doesn't tell you when it's just guessing.
Every prediction is paired with its confidence interval and the actual research it's based on. The math is in the open. When we don't know, we tell you.
Designed by people who care about typography, white space, and the quiet poetry of cream paper. Share cards you'd actually want on your fridge.
Every prediction calculator is free forever. No paywalls, no “create an account to see your results.” The science stays open.
Optional paid tools (like Face Aging — $8 for four variants), a few honest affiliate links to gear we actually like, and one tasteful ad slot. No tracking pixels, no autoplay video, no shame.
Will They is built and edited by Craig Spergel, DO — a practicing physician — with a small group of designers and parents. The medical and clinical writing on this site is authored or reviewed by Dr. Spergel personally; the calculator math is open in the methodology for any reader to check.
We started this because every other baby calculator online looks like it was made in 2008, hides the math, and doesn't tell you when it's just guessing. We build slowly. We ship things we'd be proud to send our friends. When we don't know, we say so.
Reach a real person at hello@willthey.baby — story leads, corrections, calculator suggestions, partnership inquiries. Usually replied to within a couple of days.