# Choosing a Swaddelini sleep sack size by baby's weight Which sleep sack size should be bought for a baby, based on the baby's weight? Swaddelini Swaddle Sleep Sack: Small fits babies 6\-12 lbs; large fits 12\-18 lbs comfortably; babies born over 9 lbs should still get the small\. Swaddelini Rainbow Swaddle Sleep Sack: Two sizes are chosen by the baby's weight: Small fits 6\-12 lb and Large fits 12\-18 lb comfortably, and a baby born 9 lb or more should still start in the Small because the Large will be too big\. Swaddelini Lavender Swaddle Sleep Sack: Two sizes: Small fits 6\-12 lb and Large fits 12\-18 lb; a baby born over 9 lb should still take the small because the large will be too big\. Swaddelini The Gift Swaddle Sleep Sack \(Red\): Choose size by weight: small fits 6\-12 lbs; if baby is born 9 lbs\+, still choose small; large fits 12\-18 lbs comfortably\. ### 1. [Swaddelini Swaddle Sleep Sack](/products/ucp/strolleria-com/7961557368906) (sold by strolleria\.com) Small fits babies 6\-12 lbs; large fits 12\-18 lbs comfortably; babies born over 9 lbs should still get the small\. - Size by weight: Small fits babies 6\-12 lbs; large fits 12\-18 lbs comfortably; babies born over 9 lbs should still get the small\. (manual) - Fit check: It should fit snugly with arms able to move to midline; if too tight, leave arms out or size up; light compression helps sleep; too loose is less effective\. (manual) - Stop arms\-in: The page says to stop arms\-in use as soon as a baby shows any sign of rolling, which can happen as early as two months\. (blog) ### 2. [Swaddelini Rainbow Swaddle Sleep Sack](/products/ucp/strolleria-com/7961557794890) (sold by strolleria\.com) Two sizes are chosen by the baby's weight: Small fits 6\-12 lb and Large fits 12\-18 lb comfortably, and a baby born 9 lb or more should still start in the Small because the Large will be too big\. - Size by weight: It lists Small as 6\-12 lb \(2\.7\-5\.4 kg\) and Large as 12\-18 lb \(5\.4\-8\.2 kg\)\. (review) - Fit check: - - Stop arms\-in: - ### 3. [Swaddelini Lavender Swaddle Sleep Sack](/products/ucp/strolleria-com/7961558188106) (sold by strolleria\.com) Two sizes: Small fits 6\-12 lb and Large fits 12\-18 lb; a baby born over 9 lb should still take the small because the large will be too big\. - Size by weight: Two sizes: Small fits 6\-12 lb and Large fits 12\-18 lb; a baby born over 9 lb should still take the small because the large will be too big\. (manual) - Fit check: A buyer of an 11 lb, 10\-week\-old said she would not recommend it for babies over 10 lb: her baby kept pulling her hands up toward her head, could not get them to her mouth and became frustrated\. (guide) - Stop arms\-in: - ### 4. [Swaddelini The Gift Swaddle Sleep Sack \(Red\)](/products/ucp/strolleria-com/7961557991498) (sold by strolleria\.com) Choose size by weight: small fits 6\-12 lbs; if baby is born 9 lbs\+, still choose small; large fits 12\-18 lbs comfortably\. - Size by weight: It is sold in two weight\-based sizes: Small \(6\-12 pounds\) and Large \(12\-18 pounds\)\. (listing) - Fit check: Parents report a snug yet flexible fit that can soothe babies who struggle with traditional swaddles\. (review) - Stop arms\-in: - ## Also cited in the text - Swaddelini Rainbow Swaddle Sleep Sack, sizing: Two sizes are chosen by the baby's weight: Small fits 6\-12 lb and Large fits 12\-18 lb comfortably, and a baby born 9 lb or more should still start in the Small because the Large will be too big\. (guide) - Swaddelini The Gift Swaddle Sleep Sack \(Red\), sizing: Choose size by weight: small fits 6\-12 lbs; if baby is born 9 lbs\+, still choose small; large fits 12\-18 lbs comfortably\. (guide) Every value in the table is a fact RoboTrunk checked, linked to the page it came from\. A dash means no checked fact fills that cell\. Prices and stock change, so this page prints neither: each product name links to its RoboTrunk page, which shows them live\. Written 2026-10-17T12:55:17.413Z. This page is published by RoboTrunk, a store built for shopping agents. The store named on this page sells the product and ships it. RoboTrunk is not the seller and never holds the money. 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