TOG Ratings Explained: A Plain-English Guide for Australian Parents

What a TOG rating actually measures

TOG is a textile measure of thermal resistance — how well a material slows the escape of body heat. It's the same unit used to rate duvets and quilts, and it's printed on the label of every baby sleeping bag (also called a sleep sack) sold in Australia. A 2.5 TOG bag traps more warmth than a 1.0 TOG bag; a 0.2 TOG bag is barely more than a single light layer of fabric.

The number on its own doesn't tell you whether a bag is right for tonight. A TOG rating only becomes useful when you read it against two things: the temperature of the room your baby sleeps in, and what they're wearing underneath. A 2.5 TOG bag is well matched at 18°C and far too warm at 24°C — same bag, different room. That's the whole idea behind TOG: it lets you pair a known amount of warmth to the conditions in front of you.

The TOG scale for baby sleeping bags

Most Australian brands — ergoPouch, Love to Dream, Bubba Blue, Grobag — stock four standard ratings. Each one is built for a different kind of room:

• 0.2 TOG — barely-there warmth for hot rooms (24–26°C), often just a light cotton or muslin layer. Common in Queensland and the Top End through summer.
• 1.0 TOG — light warmth for mild rooms (22–23°C). The all-rounder for spring and autumn across most of the country.
• 2.5 TOG — the most widely used rating, for cool rooms (18–21°C). If you own one bag, it's usually this one.
• 3.5 TOG — maximum warmth for cold rooms (below 18°C). Earns its place in Melbourne, Canberra, Tasmania, and the alps over winter.

Do I need every TOG?

No. A few brands also make a 0.5 or 1.5 TOG to fill the gaps, but the four ratings above cover almost every Australian night. Most families manage perfectly well with two bags — a 1.0 TOG and a 2.5 TOG — and add a 0.2 or a 3.5 only if their climate genuinely calls for it. Buy for the rooms you actually have, not for every temperature on the chart.

TOG by room temperature: the chart

This is the reference most parents are really after — which TOG to use at which room temperature, and what to put on underneath. The bands below reflect general Australian safe-sleep guidance:

How to read the boundaries

Treat the band edges as guides, not hard lines. At the top of a band — 21°C in the 2.5 TOG range, for instance — keep an eye on whether the room drifts warmer overnight, because one degree up moves you into 1.0 TOG territory. At the bottom of a band, watch for the room getting colder.

For a temperature-and-age-specific answer, the SleepSnug calculator does the maths for you, or you can browse the room-by-room TOG guides for a worked example at your exact temperature. Both are free and grounded in the same bands as the chart above.

Why TOG matters more in Australian homes

TOG charts were largely written for the northern hemisphere, where central heating holds a nursery at a steady temperature all night. Most Australian homes don't work like that. Older brick-veneer, weatherboard, fibro and Queenslander houses are poorly insulated, and heating is often a single reverse-cycle unit in the living room — not the bedroom. A nursery that reads 19°C at bedtime can fall to 14°C by pre-dawn.

That overnight swing is why a static chart isn't enough on its own. In a 16°C Adelaide Hills winter bedroom, 3.5 TOG is the safe call because the room only gets colder through the night. In a 25°C Perth summer room the opposite is true — the Fremantle Doctor sea breeze can drop the temperature several degrees after midnight, so a 0.2 TOG bag plus aircon is the starting point. Same baby, opposite ends of the scale, both correct.

Humidity matters too. A 26°C night in humid Darwin feels warmer to a baby than the same reading in dry inland heat, because sweat evaporates more slowly. When the room is warm and sticky, lean cooler than the chart suggests and rely on the touch test.

Combining TOG with what's underneath

The TOG is only half the equation — what your baby wears inside the bag does the fine-tuning. The clothing column in the chart is your starting point. From there, adjust by a single layer rather than jumping a whole TOG: a short-sleeve bodysuit instead of long sleeves, or a singlet instead of a bodysuit.

Newborns are the exception worth flagging. Babies under about three months regulate their temperature less well than older babies, so they sometimes need one extra layer for the same room — but never a higher TOG than the chart suggests, and never a loose blanket under 12 months. Red Nose Australia recommends a fitted sleeping bag with a fitted neck and armholes and no hood as a safer alternative to blankets, because it can't ride up over the face.

Once a baby starts rolling — often around four to five months — a fitted sleeping bag also becomes safer than a swaddle, since the arms are free to push up. The TOG you choose doesn't change when rolling starts; only the format does.

A worked example: one bag at three temperatures

Say you own a single 2.5 TOG bag — the most common starting point. At 19°C, that bag over a long-sleeve bodysuit is well matched: your baby's chest should feel comfortably warm at the late-night feed, not cool and not damp. At 21°C, the same bag is at the top of its range — drop to a lighter layer underneath, such as a singlet, and check the chest isn't sweaty by morning.

At 24°C, though, that same 2.5 TOG bag is the wrong tool. A baby in it with any layer underneath can be flushed and damp within half an hour, because the bag is built to hold in roughly twice the warmth the room calls for. That's the moment to reach for a 0.2 TOG bag — not to strip the clothing under a bag that's too warm to begin with. One bag stretches across a couple of degrees by changing the layer underneath; it can't stretch across the whole chart.

How TOG compares to blankets and wraps

Because TOG is the same unit used for adult bedding, parents often ask how a sleeping bag compares to a blanket. For babies, the comparison isn't a useful one: Red Nose Australia advises against loose blankets, wraps that can come undone, and anything that can cover the face for babies under 12 months. A fitted sleeping bag of the right TOG does the job a blanket would — without the risk of it riding up — which is exactly why bags have become the standard. If you've been handed a TOG figure for a quilt or blanket, treat it as background interest rather than a setting to copy.

Will washing change a bag's TOG?

A sleeping bag's TOG is set by its construction — the fill and the number of fabric layers — so a normal wash won't change the rating. What does shift warmth over time is matting: cheaper polyester fill can clump and thin after many hot washes, leaving cold spots. Following the care label (most Australian bags are happy at 40°C) keeps the rated warmth honest, and cotton or bamboo bags tend to hold up better than budget synthetics at the warm end of the scale because they breathe rather than trap moisture.

What a TOG rating can't tell you

A TOG rating is a warmth measure, not a safety guarantee. The most common mistake is over-dressing — reaching for a high-TOG bag plus several layers because a cold baby feels like the bigger worry. In practice, overheating is the greater risk: it's recognised by Red Nose Australia as a contributing factor to Sudden Unexpected Death in Infancy (SUDI), which is why every band on the chart leans toward the lighter option at the boundary.

Check your work with the touch test. Feel your baby's chest or the back of the neck — it should be warm, not damp or hot. Cool hands and feet are normal and not a sign your baby is cold. If the chest is sweaty or the hair is damp at the hairline, drop a layer or step down a TOG on the next sleep.

And measure the room rather than guessing. A cheap room thermometer — many video monitors include one — turns the chart from approximate to accurate. Bedrooms often run several degrees different from the hallway where a ducted thermostat reads, so the living-room temperature isn't the number you want.

Try the SleepSnug calculator

If you'd rather not hold the chart in your head at 2am, the SleepSnug calculator takes your room temperature and your baby's age and returns the exact TOG and clothing combination in a few seconds — including how tonight's forecast is likely to shift the room overnight. It's free and needs no account.

Frequently asked questions

Related reading

• Room-by-room TOG guides for every temperature
• What a 3–6 month old should wear at 16°C
• What a 3–6 month old should wear at 25°C
• Get tonight's recommendation from the SleepSnug calculator
• Red Nose Australia — safe sleep guidance

Sources

• Red Nose Australia — rednose.org.au
• Raising Children Network — raisingchildren.net.au