Baby Weight Guessing Game: How to Play It, Score It and Guess Smart

Ask ten people to guess a baby's birth date and most of them will land within a week of each other. Ask the same ten people to guess the weight, and suddenly grandma says "at least nine pounds, look at that belly" while your best friend confidently writes down a number that would fit a kitten.

That is exactly why the weight guess is the best part of any baby pool. Nobody has inside information, nobody can look it up, and the reveal is a genuine surprise for everyone, parents included. Here is how to run a baby weight guessing game, how to decide who wins, and what the numbers say if you want your own guess to be a smart one.

How the game works

The setup takes two minutes:

1. Everyone submits one weight guess before an agreed deadline. Set the deadline a few weeks before the due date, so nobody can "guess" after a late ultrasound estimate starts making the rounds in the family group chat.
2. The baby arrives and does the only official weigh-in that counts. The number on the hospital scale is final. No rounding in anyone's favor.
3. The closest guess wins. Bragging rights at minimum, a small prize if you are feeling generous.

That is the whole game. The fun is in the details: how precise people must be, how you settle a near-tie, and whether you let the parents play (we say no, they have seen the ultrasound estimates).

What do babies actually weigh?

This is where you can quietly outsmart the whole family. Most people guess based on vibes; you can guess based on statistics.

	Average	Typical range
Full-term newborn	7 lb 8 oz (3.4 kg)	5 lb 8 oz to 8 lb 13 oz (2.5 to 4.0 kg)

A few patterns worth knowing before you commit to a number:

• Boys are slightly heavier than girls on average, by roughly 3 to 4 ounces (about 100 grams). If the sex is known, adjust.
• Later means heavier. A baby born at 41 weeks is usually noticeably heavier than one born at 38. If you think this baby is taking its time, guess higher.
• Second babies tend to weigh a little more than firstborns. Not a law, but a real trend.
• The bump tells you almost nothing. Belly size mostly reflects fluid, position and the parent's build. Grandma's nine-pound prediction is folklore, not data.

So the boring, statistically sound guess is somewhere around 7 lb 5 oz to 7 lb 11 oz (3.3 to 3.5 kg). Which brings up the strategic problem: if everyone guesses the average, everyone is bunched together. The players who win weight pools usually pick a precise, slightly unusual number, like 7 lb 3 oz or 8 lb 1 oz, and claim all the space around it.

Three ways to pick a winner

Decide this before the guesses come in, and write it where everyone can see it. Weight disputes are surprisingly passionate.

1. Closest guess wins. The simplest rule: smallest difference between guess and actual weight takes it. Works for any group size, and ties are rare if you require guesses to the ounce (or to 10 grams).

2. Closest without going over. The Price is Right rule. Guessing above the actual weight knocks you out, so everyone shades their guess low, and the reveal gets a game-show tension the simple version does not have. Great at a baby shower with the guesses read out loud.

3. Points on a sliding scale. In a bigger pool where people also guess the date, time and length, weight becomes one category on the scoreboard. The system we use gives weight 10 points on a sliding scale: full points for a near-exact guess, fading to zero once you are more than about a pound (500 grams) off. The full breakdown is in our baby pool rules, including why weight deserves more points than the birth date: everybody knows the due date, but weight is a genuinely open question.

Whichever you choose, agree on one tie-breaker in advance. Closest birth time is the classic, and it resolves almost anything.

Make it a real pool

The weight guess on its own is a lovely five-minute shower game. It becomes a weeks-long family event when you combine it with the other classics: birth date, time, length, hair color, and the boldest one, the name. One form, one deadline, one scoreboard, and every relative from your college roommate to your uncle in another time zone checking the leaderboard.

If the date is the guess your crowd cares about most, we wrote a whole guide to betting on the birth date too. Together, date plus weight is the classic combination: one guess everyone thinks they can win, one guess nobody can.

Paper chart or online?

A printed chart with a column of names and a column of guesses works fine for a shower where everyone is in the room. It stops working the moment half the players are somewhere else: the chart lives at one house, someone transcribes guesses from three group chats, and on the big day a sleep-deprived new parent is doing ounce arithmetic in a hospital chair.

The online version fixes all of that. Start a baby pool, share one link (or put the QR code on the shower table next to the cake), and everyone enters their weight guess on their own phone, in pounds or kilos. When the baby arrives, you type in the real numbers once, and the ranking sorts itself out while you get back to the actual point of the day: staring at the baby.

However you run it, the weight guess earns its place in every pool for one simple reason: it is the question where the confident people are wrong the most. And there is no sweeter moment in a baby pool than watching grandma's nine-pounder arrive at a dainty 6 lb 14 oz, exactly seven grams from your guess.