I've tested America's firmest mattresses — this is the one I'd buy in the Labor Day sales

The Plank Firm Mattress on a bed frame in a bedroom. In the bottom right corner is a Tom's Guide price drop badge
(Image credit: Future)

When you're a stomach sleeper, you get used to starting the day with back pain. I used to spend a good few minutes each morning trying to ease life back into my hips. Then I discovered the Plank Firm mattress, 30% off at Plank this Labor Day, and now I know what it's like to wake up feeling fresh.

The Plank Firm is unusual. When it comes to construction and quality, it can rival the best mattresses we've tested. However, this double-sided bed is super firm and incredibly flat. That's heavenly for stomach sleepers (and many back sleepers) but it's not a feel everyone will enjoy.

Where the Plank Firm excels is full-body support, and I'll explain below why that's so important for stomach sleepers. But if you're after something a little softer, check out the deals in our Labor Day mattress sales hub.

Plank Firm (twin)
Save 30%
Plank Firm (twin): was $749 now $524.30 at Plank Mattress

A 2-in-1 mattress with a specialist design at under $1,000 for a queen: the Plank Firm is superb value for money. And today's 30% off sale is the best you'll see, with a queen-size just $932.40 (was $1,332). I've observed a shift in sales strategy at Plank recently, moving away from long-running deals and towards short-lived sales. In other words, shop now before 30% off drops back to 25%. A 120-night trial and lifetime warranty are included.

Our Plank Firm mattress review: ★★★★½
User score: ★★★★½ (4,100+ reviews)

Why the Plank Firm is my favorite mattress for stomach sleepers

Stomach sleepers, there may not be many of us but we know there's nothing more comfortable than burrowing into your bed face first. However, stomach sleeping does come with a (fairly major) downside. It's hell on your back.

The best firm mattresses help offset that problem. On a softer bed, stomach sleepers will often find their body sinks at the hips. This puts strain on your muscles, as they work overtime to keep your spine aloft.

A person lies in a stomach sleeping position on the Extra Firm side of the Plank FIrm mattress

(Image credit: Future)

But firm beds hold the spine straight. By maintaining natural alignment, your body can relax and you'll wake up feeling fresh. For that reason, most of the best mattresses for stomach sleepers are firm.

It's not just stomach sleepers who can benefit from a firm mattress. Back sleepers often need extra support at the spine, while even some side sleepers (particularly those with a heavier build) can appreciate firm support.

And when it comes to firm, even support, no mattress has impressed me like the Plank Firm.

Well. Maybe these two came close...

More firm mattresses I've tried and loved

Plank Firm Luxe (twin)
Save 30%
Plank Firm Luxe (twin): was $1,065 now $745 at Plank Mattress

Plank Firm's luxurious upgrade, the Plank Firm Luxe is the best hybrid mattress for firm support. Like the Plank Original, this is a dual-sided mattress with a firm feel. However, it adds springs, for better airflow (but slightly worse edge support). With 30% off the Luxe is now $1,118.60 (was $1,598), which is the lowest price you're likely to see.

Our Plank Firm Luxe mattress review: ★★★★
User score: ★★★★½ (3,200+ reviews)

Siena Signature (twin)
Siena Signature (twin): $159 at Siena

The best cheap mattress we've tested, the Siena Signature offers firm comfort on a budget. Like the Plank Firm, this is a memory foam mattress that excels at motion isolation and edge support, but this cheaper design is unlikely to have the durability of the Plank. However, with a queen just $349, and a 180-night trial and 10-year warranty included, it's excellent value.

Our Siena Signature mattress review: ★★★★
User score: ★★★★½ (3,600+ reviews)

Labor Day mattress sales 2026: More deals at a glance


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Ruth Jones
Senior Sleep Staff Writer

Ruth is an experienced Senior Staff writer at Tom’s Guide, covering all things sleep and mattresses. She writes to help people sleep better, from how-tos to the latest deals to mattress reviews, and has interviewed an array of experts who share her passion. She is also our specialist on memory foam — she’s flown around the world to see memory foam being made — and leads our hotel mattress content. She has a deep interest in the link between sleep and health, and has tried enough mattresses, from Helix to Nectar to Simba, to know the right bed really can make a difference to your wellbeing. Before joining the team at Tom’s Guide, Ruth worked as a sleep and mattress writer for our sister website, TechRadar.

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