What sizes do innerspring mattresses come in?

Casper gives a height range for Twin XL and identifies bedroom footprint as a Queen consideration.

Twin XL

Casper says Twin XL’s extra length can make a real difference for sleepers between 5 feet 10 inches and 6 feet 5 inches.

• Compare the sleeper’s height with that range.
• Note the stated height range for Twin XL sleepers.

Queen

For Queen, consider bedroom footprint along with sleeping space.

• Check the space available in the bedroom before choosing.
• Keep sleeping space in the comparison too.

Split names describe different setups, so check which pieces the product listing includes.

Two Twin XLs

A Split King is a paired mattress setup.

• For Flexabed, check the product listing for the pair’s dimensions.
• An adjustable frame can let two sleepers set head and foot elevations independently.

Two 36-by-84 halves

A Split California King consists of two separate mattresses.

• Ashley describes its two-mattress Split California King setup as longer and narrower than two Twin XLs.
• For Ashley’s Split California King, check the listed dimensions of both pieces before ordering.

The examples include split choices, custom sizing, and an Avocado mattress with a listed size range.

• Flexabed lists Split King pairs in 38-by-74, 38-by-80, or 38-by-84-inch sizes, and offers soft, medium, and firm innerspring options.
• Mattress Insider offers custom sizes and shapes for its RV innerspring when a listed size does not fit.
• The mattress described in Avocado’s specifications is available only in Twin, Twin XL, and Full.
• Dreamfoam Essential is an all-foam mattress, not an innerspring example.

RV mattresses have no industry standard like regular home mattresses, although some sizes are common.

• The Original Mattress Factory lists a Short Queen.
• RV makers such as Airstream, Winnebago, and Casita use other special sizes.
• Original Mattress Factory says it can make mattresses in nearly any shape and size.

One RV innerspring model is about 8 inches high, while the Saatva Classic is listed in 11.5- and 14.5-inch heights; adjustable-base use is limited to the lower height.

Measure the full bed setup, including the mattress, foundation, and frame, to judge how easily you may get in and out.

Avocado’s published per-size specifications show that coil counts differ by mattress size.

Compare counts within one model, rather than across brands or models.

Rooms To Go lists Twin XL at 38 by 79.5 inches, with a listed negative tolerance and minimum dimensions of 37.5 by 79 inches; Queen is 60 by 79.5 inches, with a listed negative tolerance and minimum dimensions of 59.25 by 78.75 inches.

For a Mattress Insider custom build, note that it may deviate up to 1.5 inches in either direction from the original measurements.

Before buying, check measurement details, full height, and room clearance, plus the bed-support rule for the exact model and platform.

1. For a Magic Sleeper custom mattress, round measurements to the nearest half inch; if between sizes, choose slightly smaller rather than larger.
2. For an angle cut on that custom mattress, measure X across the width and Y along the length, starting at the platform corner.
3. For a Saatva Classic on a slatted platform, check that slats are at least 3 inches wide and spaced less than 4 inches apart.
4. Measure the full height with the mattress, foundation, and frame included.
5. Casper suggests taping the mattress outline on the floor to visualize clearance for doors, closets, and lamps.

Are Split King and Split California King available in every model?

The available evidence does not establish availability in every model for Split King and Split California King. Saatva lists Split California King only for its Classic 11.5-inch and Solaire models; its Classic page lists both split sizes, while Flexabed lists Split King choices at 38-by-74, 38-by-80, or 38-by-84 inches.

What does Split King mean?

A Split King means 2 Twin XL mattresses placed side by side, with an overall size of 76 by 80 inches.

Is Twin XL the same length as Queen or King?

Twin XL is 80 inches long and 5 inches longer than Twin, but the available facts do not give Queen or King lengths, so check those listings before assuming they match.

We read 13 published pages from 11 sites (help.avocadogreenmattress.com, Saatva, ashleyfurniture.com, Casper and 7 more), checked in October 2026. Every sentence in the answers above cites one of them; the offer card at the end names its own source. This page reports published sources only; we did not test mattresses in person.