Helix Split King buying guide · Updated September 23, 2026
Can you build a Helix Split King? Yes. Put two Helix Twin XL mattresses side by side. Each measures 38 by 80 inches, giving you the 76-by-80-inch footprint of a standard king. You can choose different models for the two sleepers. For separate head and foot adjustment, pair them with a compatible Split King adjustable base that operates each side independently.
Our starting recommendation: choose both halves from the same Helix collection, confirm the finished heights with your selected upgrades, and select each sleeper’s comfort independently. Midnight Luxe plus Dusk Luxe is a pairing to consider when a side sleeper shares with a back or combination sleeper.
This guide helps you specify the setup. For individual mattress performance and testing, follow the linked Yawnder reviews below. The pairings here are buying recommendations, not claims that we tested every combination together.
Which Helix mattresses should you pair?
Choose based on each person’s needs before choosing the collection. Body weight, shoulder sensitivity and preferred feel can change the right answer even when two people use the same sleep position.
| Couple’s needs | Pairing to consider | What to check |
|---|---|---|
| Both prefer a medium feel for side sleeping | Midnight Luxe + Midnight Luxe | Whether each sleeper gets enough shoulder cushioning. |
| Side sleeper + back or combination sleeper | Midnight Luxe + Dusk Luxe | Try each model individually; similar firmness labels do not mean identical feel. |
| Side sleeper + partner who wants a firm surface | Midnight Luxe + Dawn Luxe | The firmer partner should confirm comfort in their usual position. |
| Both want to explore the Elite collection | Two Twin XL Elite models | Final mattress height, sheet depth and ease of getting into bed. |
These starting points follow Helix’s model guide. They are not a guarantee of personal fit.
Midnight Luxe: start here for the side-sleeper half
Read our Helix Midnight Luxe review before choosing this side. Pay particular attention to how the reviewer’s body type and sleep position compare with yours. A mattress that suits one partner can still feel too firm or too soft to the other.
Dusk Luxe or Dawn Luxe: choose the other half deliberately
Use the Dusk Luxe review and Dawn Luxe review to compare the alternatives. A Split King is useful when choosing the same mattress would leave one sleeper making a substantial comfort compromise.
Considering Elite?
Read our Midnight Elite review and Midnight Luxe versus Midnight Elite comparison. Decide whether the upgrade matters to both partners before pricing two halves.
Match the height, even when you mix firmness
Helix’s current collection guide lists Core at 11.5 inches, Luxe at 13.5 inches and Elite at 15 inches. Staying within one collection is a useful starting point for a level sleeping surface. Confirm both finished specifications before ordering, especially when selecting different cover or comfort upgrades.
Mixing collections can create a step down the middle. Do not assume a topper or different base leg height will solve this cleanly: it changes the setup and may complicate articulation. Ask for a written configuration check that names both mattresses, upgrades and bases.
Which adjustable base works?
Helix states that all of its mattresses are designed to work with its adjustable base. For another manufacturer’s base, verify the exact mattress and base pairing, including support requirements, dimensions and load limits.
A Split King base must give you two independently controlled sides if that is the feature you want. Helix explains independent and synchronized operation here. A one-piece king mattress will not give two sleepers separate mattress movement.
- Confirm that the quoted base includes both halves and the required controls.
- Check fit inside your bed frame, including clearance and any slats that must be removed.
- Check the base’s capacity against the mattress and sleeper loads according to its instructions.
- Measure total bed height with the chosen mattress and base legs.
What does a complete Helix Split King setup cost?
Complete total = left Twin XL + right Twin XL + base configuration + bedding and protectors + applicable delivery, setup and tax. Price each selected half separately. A queen promotional price or a single Twin XL price does not tell you the Split King total.
We have not verified a checkout total for every combination, so this guide does not present a starting price as a complete package quote. Use the official Midnight Luxe selector and Helix adjustable-base selector, or request an itemized Yawnder quote for your exact setup.
| Line item | Quantity or configuration | Confirm before paying |
|---|---|---|
| Mattresses | Two Twin XL, chosen separately | Model, collection, upgrades and price of each half. |
| Support | One complete Split King base arrangement | Both sides included; independent controls if desired. |
| Protectors and fitted sheets | Two Twin XL protectors and fitted sheets | Pocket depth fits the finished mattress height. |
| Delivery and assembly | Seller-specific service | What is included, what costs extra and who assembles it. |
| Final charges and terms | Itemized checkout or written quote | Tax, discounts, mattress trial and separate base return policy. |
Compare the final payable totals for equivalent configurations. Mattress trial terms should never be assumed to cover the adjustable base or accessories; use the policies of the seller taking your order.
Living with two mattresses
The center seam is the main compromise. Two separate fitted sheets let each side move freely. A shared king comforter can still cover the bed, but a shared topper or tightly fitted bridge can interfere with the separate movement you bought the setup for.
For sliding and gaps, start with our guide to keeping a Split King together. If you frequently sleep across the center and do not need separate adjustment, compare a shared king or another split-firmness approach before buying.
Before you order
- Choose each person’s mattress independently.
- Confirm both are Twin XL, with matching finished heights.
- Verify base compatibility and separate controls.
- Get the full itemized price and seller-specific return terms.
- Check delivery access and total bed height.
Want help narrowing the pair? Contact Yawnder with both sleepers’ positions, preferred feels and your existing base model. Select models may be available to try at our Encinitas showroom; confirm current floor availability before visiting.
Frequently asked questions
Is a Helix Split King one mattress or two?
The setup described here uses two separate Twin XL mattresses. Select two halves when ordering rather than assuming that one king mattress has independent sides.
Can we use different Helix models?
Yes, provided you specify compatible sizes and support. Check finished heights and selected upgrades so the two surfaces align.
Do two regular twin mattresses make a king?
No. Regular twins are shorter. Use Twin XL for the standard 80-inch-long Split King arrangement. See Helix’s Twin XL dimensions guide.
Do we need an adjustable base?
No. Separate mattresses can address different comfort preferences on suitable stationary support. An independently operating Split King adjustable base adds separate positioning.
Is this the same as a split California king?
No. This guide specifies a standard king footprint using two Twin XL mattresses. Do not order a split California king base for this configuration.