Quick answer: TOG is a warmth rating, not a universal dressing prescription. A 0.5 TOG sleep sack is lighter than a 1.0 or 2.5 TOG option, but the number does not account for the room, the layer underneath, the garment's sleeves and feet, its fit, or how an individual baby responds. Start with the chart for the exact product, use the bedroom temperature rather than the outdoor forecast, and treat fit and safe-sleep basics as separate checks.
That distinction matters in Canada. A Vancouver bedroom can stay warm through a rainy January night, while an air-conditioned room in July may feel much cooler. Shopping by season alone can therefore put the wrong weight in the drawer. This guide shows how to compare sleep sacks and wearable blankets without pretending that one TOG chart works for every baby or every brand.
What does TOG mean on a sleep sack?
TOG is a way of describing thermal insulation: as the rating rises, the garment is intended to provide more warmth. It is useful because it gives shoppers a common starting point. It is limited because a number on a label cannot describe the entire sleepwear system.
For example, compare a sleeveless muslin bag, a sleeveless insulated bag and a long-sleeve footed sleep bag. Even when each carries a TOG rating, the cut, fabric, fill, coverage and recommended layer underneath may differ. The manufacturer's temperature chart belongs to that product; it should not be copied automatically to another garment with the same rating.
0.5 vs 1.0 vs 2.5 TOG at a glance
| Rating | What the rating helps you compare | Current product example | What still needs checking |
|---|---|---|---|
| 0.5 TOG | A lighter-weight option within a maker's sleepwear range. | Loulou Lollipop lists its 0.5 TOG muslin sleep bag for rooms from 24 to 27 C. | Base layer, size, neck and arm opening fit, and whether the room stays warm all night. |
| 1.0 TOG | A middle rating that may suit a moderately warm room, according to the exact maker's chart. | Loulou Lollipop lists its Canada-print 1.0 TOG sleep bag for 68 to 72 F, or about 20 to 22 C. | Fabric and fill, what is worn underneath, and overnight room-temperature changes. |
| 2.5 TOG | A warmer option within a maker's range. | Nest Designs lists its 2.5 TOG raglan long-sleeve footed sleep bag for rooms from 16 to 20 C. | Built-in sleeve and foot coverage, the maker's layer advice, size, and the child's comfort. |
Read the table as three product examples, not a universal temperature chart. The ranges above come from the manufacturers' current pages for those exact garments. Another 0.5, 1.0 or 2.5 TOG product may publish a different range or layering guide.
A five-check method for choosing a TOG
1. Measure the room you are actually dressing for
Put the temperature reading near the sleep space, away from a sunny window, heater or direct vent, and notice what happens after the household goes to bed. The useful number is the bedroom temperature during the sleep period, not the daytime high, the weather-app reading or the season printed on a product collection.
If the room swings several degrees overnight, a single snapshot at bedtime will not describe the whole night. That is a reason to review the room setup and the maker's instructions, not a reason to invent an in-between TOG by adding loose bedding.
2. Read the chart for the exact garment
Match the product name, TOG and construction before relying on a chart. A brand may sell sleeveless bags, long-sleeve bags, footed sleep suits and swaddle products under the same broad sleepwear menu. Their coverage and age or stage instructions can differ.
A screenshot saved months ago can also outlive a product update. Recheck the current product page and the care label when you change sizes or replace a garment. If the retailer page and the garment label disagree, pause and confirm with the manufacturer rather than averaging the two.
3. Treat the base layer and sleep sack as one system
A TOG number does not tell you what is underneath. A short-sleeve bodysuit, fitted sleeper and long-sleeve footed garment provide different coverage. Use the maker's layer guide for that specific product and avoid adding a hat or outdoor clothing indoors. Health Canada advises dressing a baby in simple, fitted sleepwear that is appropriate for the room and keeping the baby warm, not hot.
4. Check fit independently of warmth
Warmth cannot rescue a poor fit. Health Canada says a sleep sack should be the right size: one that is too large can allow a baby to slip down inside, while one that is too small can restrict movement of the hips and legs. Check the product's height and weight guide, then inspect the neckline and arm openings on the child rather than buying by age label alone.
Also look at the practical details that affect repeated use: Is the zipper covered near the chin? Can you open the bottom for a diaper change? Are snaps, pulls and seams intact after washing? Those questions will matter at 2 a.m. even though they are not part of the TOG rating.
5. Reassess when the room, garment or child changes
A correct choice is not permanent. Recheck after a move, a heating or air-conditioning change, a new base layer, a growth spurt or a size change. If a baby has individual health or temperature-regulation considerations, ask the child's health professional for advice tailored to that child rather than relying on a retail chart.
The cut can matter as much as the number
The three examples in this guide make that visible. The Loulou Lollipop 0.5 TOG and 1.0 TOG examples are sleeveless bags. The Nest Designs 2.5 TOG example has long sleeves and feet. That makes it especially important to read the exact layering and fit instructions instead of assuming that the only change is insulation.
Do not use this article to decide between a swaddle and an arms-free sleep sack. That is a separate stage and product-type question covered in our swaddle vs sleep sack guide. This page owns only the TOG decision.
Safe-sleep rules that a TOG label does not replace
- No extra blanket is needed with a sleep sack. Health Canada states that if a sleep sack is used, a blanket is not needed.
- Avoid weighted sleep products. Health Canada advises against weighted swaddles, sleep sacks and blankets.
- Use fitted sleepwear. Clothing that is too large can ride up, while loose parts and threads should be repaired before use.
- Skip indoor hats and outerwear. Hats, jackets and snowsuits can add heat and are not appropriate indoor sleep layers.
- Keep the sleep environment safe. TOG addresses garment warmth; it does not change the guidance for the crib, cradle or bassinet.
For the full environment rather than just clothing, use the Government of Canada's safe sleep hub.
Three Canadian room scenarios
A warm condo in winter
The outdoor temperature may be below freezing while the bedroom remains above 23 C. A "winter" label is less useful than the room reading. Compare lighter product charts first, then check the exact base-layer guidance and fit.
A cooler bedroom with stable heat
If the room stays in a cooler band, a warmer rating may appear on the relevant manufacturer charts. Still compare construction: a 2.5 TOG sleeveless bag and a 2.5 TOG long-sleeve footed bag are not identical outfits.
A hotel, grandparents' home or other unfamiliar room
Do not assume the usual home routine will transfer. Check the room after the heating or cooling has been running, bring the maker's layer guidance, and consider packing two appropriate garment weights rather than trying to compensate with loose bedding.
What to check before adding a sleep sack to cart
- Confirm the exact TOG rating and garment type.
- Read the manufacturer's current room-temperature and layering chart.
- Use the height and weight chart, then verify the neckline, arm openings and room for hip and leg movement.
- Check whether sleeves or feet are built in.
- Inspect zipper guards, snaps, seams and care instructions.
- Make sure the product is not weighted.
- Plan for the actual bedroom, not the outdoor season.
When those checks are complete, browse the current baby sleepwear and sleep sack selection. Product colours, sizes and availability can change, so use the live product page as the final specification check.
Questions parents actually ask about TOG
Is a higher TOG always warmer?
A higher TOG rating indicates more thermal insulation, but the full outfit still depends on the garment's cut, fabric, fill and base layer. Compare the maker's chart for the exact product rather than ranking by number alone.
Can I choose TOG from the outdoor temperature?
No. Use the room where the child sleeps. Heating, insulation, sunlight and air conditioning can make the bedroom very different from the outdoor forecast.
Is every 1.0 TOG chart the same?
No. Temperature and layering guidance can vary by manufacturer and garment construction. Use the chart attached to the exact item you own or plan to buy.
Does a baby need a blanket over a sleep sack?
Health Canada says that when a sleep sack is used, a blanket is not needed. A TOG choice should not be used as a reason to add loose bedding.
What if the room temperature changes during the night?
Track the room across the sleep period, review heating or cooling settings, and use the manufacturer's guidance for the conditions you observe. If you cannot keep the room reasonably stable or you have concerns about an individual baby, seek advice from a qualified health professional.
Sources checked
- Health Canada: Dressing your baby for sleep, published November 20, 2024 and page updated April 11, 2025. Accessed July 28, 2026.
- Government of Canada: Safe sleep, page updated May 12, 2026. Accessed July 28, 2026.
- Loulou Lollipop: 0.5 TOG Muslin Sleep Bag - Dancing Dragonflies. Accessed July 28, 2026.
- Loulou Lollipop: 1.0 TOG TENCEL Sleep Bag - Canada. Accessed July 28, 2026.
- Nest Designs: 2.5 TOG Raglan Long Sleeve Footed Sleep Bag. Accessed July 28, 2026.
