Collect donations and celebrate your newborn with a fun guessing game.
Create a pool for your baby and invite your friends and family to guess the birth date and weight. The person who guesses closest wins a prize determined by the pool creator.
Example Pool
How It Works
Probabilistic pricing: The more likely your guess, the more it costs
We're not just randomly slapping prices on your guesses.
Think of it like this: imagine everyone's guesses plotted on a hill. The peak of the hill is the expected due date or birth weight. If you guess right at the peak, you're paying premium prices because, well, you have the highest chance of being right.
But if you guess way out in left field, like the baby will be born 3 weeks late or weigh 12 pounds, your guess gets cheaper because you're taking a bigger risk.
We cap the prices so nobody goes broke and nobody gets to play for free. It's like surge pricing, for baby predictions…with well-meaning donations to the parents instead of corporate capitalism 😁.
Before the guesses go live, the creators pick one of these models:
- Standard: Balanced. Close guesses cost more, wild guesses cost less.
- Chill: Even if you think this baby is arriving on leap day, you're still in the game.
Basically, we're trying to make it fair while keeping it fun. There's actual math involved. If you're interested in that stuff, you can tab over to “for the nerds”.
After baby is born: Close the pool, see how close the guesses were!
After baby is born, close the pool and enter in their actual birth weight and date. The guesses will appear in a data visual + table in the order of how close they were to the actual.
The top 3 closest guesses will be crowned the winners!
Frequently Asked Questions
The money stuff, the settings, and what happens on the big day.
How do pool creators get paid?+
Connect your Stripe account when you create a pool (it takes about five minutes and only happens once — any pools you create later reuse it). From then on, every guess is paid directly into your Stripe account the moment someone guesses. No waiting for the pool to close, no payout requests, no minimums.
Stripe then deposits to your bank on their normal schedule (usually ~2 business days). Closing the pool just crowns the winner — the money is already yours either way.
How much does it cost?+
Creating a pool is free, and creators keep 100% of every guess — the full amount on the slider goes to the family.
Guessers pay a 10% platform + Stripe processing fee on top of their guess, shown as its own line at checkout. Example: a $45.00 guess charges the guesser $49.50 total; the family receives the full $45.00.
What settings do I control as a pool creator?+
- Baby name, due date, and expected weight (the pricing peak)
- Your pool URL (bellcurve.baby/baby/your-name)
- Min and max guess prices — anywhere between $10 and $200
- Pricing model: Standard (balanced) or Chill (even wild guesses stay pricey)
- Description, ultrasound photo, organizer photo, and an optional YouTube/Vimeo announcement video
- When the day comes: you close the pool with the actual birth date and weight, and we crown the winner
What min/max guess amounts do you recommend?+
Our defaults are $15 / $60, and we recommend most pools stick close to them. On our first real pool the median guess was about $46 — friends are more generous than you'd expect, and almost nobody picks the cheap joke guesses.
Don't set the max too low: roughly 1 in 10 guessers hit the $50 ceiling on that pool. A higher max means your most generous friends simply give more.
Is this betting?+
No — think of it as a donation with a game attached. Every guess is a gift to the expecting family, and the “prize” is bragging rights, not money. The pool creator keeps the guesses regardless of who wins.
Can I guess without an account?+
You need a free account to place a guess (that's how we keep your guesses and receipts together). Once you're in, you can also make any individual guess publicly anonymous — only the pool creator sees your name.
What happens when the baby arrives?+
The creator enters the actual birth date and weight, which locks the pool and ranks every guess by how close it was. The winner gets eternal glory (and the family gets the gifts). Rankings are visible to everyone on the pool page.
What if I need a refund?+
If you made a guess by mistake, contact the pool creator — they can refund any guess on their pool straight from their pool page (it's instant and irreversible). You always get 100% of your donation back, including the platform fee. Pool creators: open your pool, find the guess in the table, and hit Refund.