Designers say this exact sofa depth is the ideal for a super cozy couch that's not impossible to get up from

The first ever sofa I bought had one major issue – it wasn't deep enough. Sofa depth isn't something you particularly think about when shopping for a sofa online (which, of course, I was), and you're more likely to be worried about the length as to whether it will fit in your living room and be big enough for your family. 

However, depth is probably one of the most important things to consider when you're talking about comfort of your living room furniture. My sofa felt like you couldn't slouch into it, a problem caused by its narrow proportions and a foam base that was on the firm side. But no matter where you're buying it from, depth does matter. 

In the best modern homes, we're seeing supersize sofas as a huge design trend, especially outside of the more formal living rooms, making up dens, cinema rooms and spaces designed for 'hang-out' entertaining. They're not, necessarily, the right choice for every living room. 

'There's almost nothing more challenging than trying to get out of a deep, soft seat with any sense of decorum,' says interior designer Anya Bond, co-founder and design director of Kindly, 'so for a formal living area where they mainly entertain guests, a really deep-seated sofa is probably not the way to go. A supportive seat, reasonably firm, allowing an average-height person to place their feet on the floor, is much more suitable for this type of setting.'

So, what measurement should you look out for that balances the coziness you're looking for, without pushing the dimensions of your sofa too far? This is what the experts say.  

What is the perfect sofa depth?

To know what's considered a particularly deep sofa, you need to know the average sofa dimensions. 'There are no industry standards or hard and fast rules about seat depths in sofas, aesthetics in the design often dictate the overall shape, but you can assume most sofas with a fixed back cushion will vary between 19"-24" as a standard,' explains Anya from Kindly. 'More relaxed-looking sofas with cushion backs can be upwards of 31" - any sofa with a deep seat such as this is definitely for lounging on.' 

Designer Nicholas Kaiko prefers a deeper, more luxurious sofa in his designs, no matter the style. 'A luxurious sofa is typically a substantial piece of furniture – whatever style you’re after. 39" in overall depth is typically what we aim for, which usually means the seat is 29.5"-33.5" deep.' 

(Image credit: Kindly)

Does your sofa filling make a difference? 

The sofa filling will not only make a difference to the overall comfort but also to how much you sink into it - something you may or may not want to do depending on the space. 

'Your guests are far more likely to relax and remain engaged without the fear of spilling their beverages and reaching the nibbles on the coffee table with more ease,' interior designer Anya says. 

For Nicholas Kaiko, feathers are essential for a luxury living room, looking for a sofa with that sink-in feeling. 'If you want a luxurious sofa you need some feathers!' he tells us. 'I like a high-density upholstery foam core with a feather wrap a bit like a duvet. It's more work to keep these cushions looking their best, but trust me, nothing looks and feels like real feather.'

'If luxury to you is about kicking off your shoes and curling up on a living room sectional that envelopes you at the end of a hard day, then the deeper the seat the better,' Anya adds,  'and a feather-filled seat does exactly that but will leave a firm bottom indentation when you leave it. For some of us, this relaxed look is exactly what we love and for others, it can be an annoyance to have to re-plump the cushions after every use.'

What style of sofa is best suited to relaxing on?

The style will dictate how comfortable your sofa is, too. 'For me, a luxe deep sofa needs big wide arms – whether that’s a traditional rolled style or square,' suggests interior designer Nicholas Kaiko. 'I'd also say a low (or even no) foot to the sofa, for main living spaces anyway.' 

Think of materials, too, informed by how you're going to use this sofa. For example, my problem sofa was made with stylish, light-grey wool, which looked great but was itchy to any bare skin exposed to it.  'Whether your style is contemporary or classic, the look and feel of velvet is always a luxurious option,' suggest Nicholas, ' and what that velvet is made of can completely transform the same sofa. For example, a higher viscose and polyester percentage in the fabric will increase the sheen and can give a more glam look whereas cotton and linen velvets (typically a little more expensive) definitely have a more matte look and “dryer” handle or feel which is perfect for a more traditional approach to luxury.'

Where to find the best sofas

A few place which we feel stock the perfect sofas:

Lulu and Georgia - elegant yet comfy shapes

DWR - mid-century forms and classic designs

2Modern - a brilliant curation of directional and statement pieces

La Redoute - affordable and family-friendly couches