6 Best Split California King Mattresses of 2025

The Brooklyn Bedding Plank Firm Luxe is a game-changer for sleepers who demand unyielding support without sacrificing comfort. As the firmest hybrid mattress on the market, it combines a ten-out-of-ten firmness rating with a dual-sided design—offering both extra firm and medium-firm options by simply flipping the mattress. Its individually encased coils work in tandem with dense foam layers to deliver targeted pressure relief, especially for back and stomach sleepers, while the GlacioTex cooling cover combats heat retention that plagues most high-density foams.

In real-world testing, this 13.25-inch hybrid proved exceptional on adjustable bases and for couples with differing firmness preferences. Each split California king unit supports up to 950 lbs, making it ideal for heavy-duty use or combo sleepers sharing space. The coils provide excellent motion isolation—far better than typical all-foam models—so tossing and turning on one side barely registers on the other. However, edge support, while solid, doesn’t match the reinforced perimeters found in premium pocketed coil designs like those in luxury innerspring beds.

Compared to the thinner Plank Firm (B0F2GCRVQG), the Luxe model delivers superior responsiveness and breathability, thanks to its hybrid construction. It’s the clear upgrade for those willing to invest in enhanced spinal alignment and temperature control. While it lacks the plushness of memory foam hugging, that’s by design—this is a chiropractor-recommended bed built for pain relief and long-term durability. For the price, it outperforms similarly priced hybrids in support and customization, especially when paired with cooling upgrades.

For budget-conscious buyers seeking rock-solid support, the Brooklyn Bedding Plank Firm stands out as the most accessible entry into the brand’s acclaimed firm mattress lineup. This 10-inch all-foam build earns its title as the firmest all-foam mattress available, delivering a level-10 firmness that’s ideal for back pain sufferers and those who feel engulfed by softer beds. Its flippable design adds rare versatility—switch from extra firm to medium-firm—making it a smart solution for couples with mismatched comfort needs.

During extended use, the dense foam layers maintained structural integrity, showing no sagging even after months of nightly use. The split California king configuration works seamlessly on adjustable bases, and the foam’s responsiveness helps with repositioning, though it lacks the bounce of coil systems. Sleepers over 230 lbs appreciated the unwavering support, but side sleepers under 150 lbs reported pressure buildup at shoulders and hips due to minimal contouring. The optional GlacioTex cover significantly improves thermal performance, a must for hot sleepers, as the base foam retains more heat than hybrid alternatives.

When stacked against the Plank Firm Luxe (B0F2GDY37J), this model trades coil-based airflow and height for affordability and simplicity. It’s not as breathable or dynamic, but for those prioritizing spinal alignment on a budget, it’s unmatched. The Certified Safe Materials label ensures peace of mind, with no fiberglass or harmful off-gassing. While it doesn’t offer the same long-term cooling or motion separation, it delivers core benefits at a fraction of the cost—making it a high-value pick for support-first sleepers.

Engineered specifically for adjustable bed compatibility, the Blissful Nights Copper Infused split king mattress delivers a seamless blend of flexibility, support, and smart temperature control. Its articulating grooves and air grid base allow it to bend effortlessly with motorized bases, preventing foam cracking or seam splitting—a common flaw in non-adjustable-specific designs. The copper-infused memory foam provides a medium-firm feel that balances contouring with responsiveness, making it ideal for combo sleepers who shift positions frequently.

In real-world trials, the mattress excelled on zero-gravity settings, maintaining consistent support from head to heel without collapsing at hinge points. The patented edge support enhances sitting stability—perfect for reading or dressing in bed—while the temperature-regulating foam kept sleepers cooler than standard memory foam, though not as cold as gel-infused or hybrid models. However, heavier individuals (over 250 lbs) noted slight sinkage in the lumbar region, and motion transfer was moderate, making it less ideal for light sleepers with active partners.

Compared to the Sven & Son gel model (B0FBT4X13Y), this bed offers better structural integrity on adjustable frames but lags slightly in cooling performance and foam responsiveness. It’s not the softest or the firmest, but it hits a sweet spot for adjustable base users who want balanced comfort without excessive sinkage. With a 10-year warranty and CertiPUR-US certification, it’s a reliable long-term investment—particularly when you prioritize frame compatibility over elite cooling or bounce.

The Sven & Son Gel Memory Foam split California king mattress is a standout for value-driven buyers seeking cooling performance and pressure relief in one well-balanced package. Its bionic cooling gel infusion isn’t just marketing fluff—it actively pulls heat away from the body, making it a top pick for hot sleepers who dread waking up sweaty. The 12-inch multi-layer design features a quilted, heat-wicking cover and high-density base foam that ensures durability without the dreaded “sagging” common in cheaper foams.

In testing, the mattress delivered consistent support across all sleep positions. Side sleepers praised the adaptive cushioning at shoulders and hips, while back and stomach sleepers appreciated the spinal alignment and minimal sinkage. The split configuration worked flawlessly on adjustable bases, and the fiberglass-free, CertiPUR-US certified materials ensured a safe, low-odor expansion right out of the box. That said, the medium feel may be too soft for those needing orthopedic-level firmness, and the all-foam construction means slower response times compared to hybrids.

Against the Blissful Nights copper model (B07G7J2PMS), this Sven & Son version offers superior cooling and a more luxurious surface feel, though it lacks specialized articulation grooves for extreme base adjustments. It’s not the firmest or the smartest bed, but it delivers exceptional comfort and safety at a competitive price. For couples wanting a cool, safe, and supportive sleep surface that works with most foundations, this is a smarter buy than pricier specialty models.

The Ananda Split Cal King Combo redefines convenience by merging a premium adjustable base with a smartly engineered memory foam mattress into one seamless sleep ecosystem. This bundle includes dual independent bases—perfect for couples—featuring head tilt, zero gravity, anti-snore, and massage functions, all controllable via remote or Alexa voice commands. The 12-inch pearl and gel-infused foam mattress is designed to flex with the base, thanks to articulating grooves and an air channel system that prevent cracking and enhance breathability.

In practical use, the bed shines for those managing sleep apnea, acid reflux, or chronic pain. The zero gravity mode elevates legs and head to reduce spinal pressure, while the massage function offers therapeutic relief after long days. The mattress itself strikes a balanced medium-firm feel, avoiding the overly plush trap that compromises support. However, the cooling is only moderate—better than basic foam but not as effective as active cooling covers like GlacioTex. Assembly requires patience, as components arrive in multiple boxes with slight delivery lag.

Compared to the Sven & Son smart frame bundle (B0CX2X3X9H), the Ananda set offers nearly identical features at a lower entry price, though it lacks under-bed lighting and has a shorter 10-year warranty versus 25 years. It’s not the most futuristic bed, but it delivers 90% of smart bed benefits with strong durability and ease of use. For couples wanting personalized positioning, massage, and voice control, this bundle offers the best feature-to-value ratio among adjustable setups.

The Sven & Son Smart Frame Bundle is the ultimate expression of luxury sleep technology, combining a feature-rich adjustable base with a high-performance gel memory foam mattress in one premium package. With head lift up to 75° and foot elevation to 45°, it supports everything from reading to acid reflux relief, while zero gravity and anti-snore presets optimize breathing and spinal alignment. The ergonomic remote includes memory settings, under-bed lighting, and multi-zone massage—features typically seen only in高端 medical beds.

Real-world testing revealed exceptional build quality: the 25-year warranty reflects confidence in longevity, and the USB ports and soft-glow lighting add daily convenience. The included 12-inch gel memory foam mattress uses bionic cooling tech and a quilted cover to enhance airflow, making it one of the coolest-running options in adjustable setups. Motion isolation is strong, and the split design allows fully independent adjustments—ideal for couples. However, the mattress, while comfortable, doesn’t match the orthopedic precision of the Brooklyn Plank models for severe back pain sufferers.

Against the Ananda combo (B07KGM7GL4), this Sven & Son bundle offers superior lighting, longer warranty, and a more intuitive remote, justifying its higher cost. It’s not the cheapest smart bed, but it’s the most comprehensive and future-ready option available. For tech-savvy sleepers who want personalized comfort, long-term durability, and hospital-grade adjustability, this is the gold standard.