# How Is Latex Density Measured?

In recent years, latex mattresses have become very popular among sleepers. Density, or weight per unit of volume, is an important consideration for latex mattress shoppers. The density of a bed’s individual latex layers can impact mattress durability, temperature, odor, and other important variables for owners, as well as cost. In this guide, we’ll explain how density is measured for latex mattress layers and shed some light on how to choose a mattress based on density.

## What Is Latex Density?

Density refers to the weight of one cubic foot of material, and is expressed in pounds per cubic foot (PCF). To calculate density, simply divide an object’s total weight by its overall volume. For example, a latex layer that weighs 100 pounds and measures 25 cubic feet has a density of 4 PCF. If the latex has a uniform consistency, then each cubic foot will weigh 4 pounds.

Latex is a liquid extract derived from the sap of rubber tree plants. Due to its natural durability and flexibility, latex has many different industrial uses today. In mattresses, two types of latex are generally used: Dunlop and Talalay. Both latex types differ in terms of their specific processing method, as well as consistency, weight, and other characteristics. A full breakdown is found in the table below.

 Type of Latex Processing Steps Consistency Firmness Weight Dunlop 1. Latex is whipped into a froth, injected into a mold, and baked in a vulcanization oven 2. Latex is removed from the oven to be washed, then baked a second time to remove moisture content Heterogeneous Fluffy, foamy material is dispersed across the top of the latex layer, while heavier sediment gathers at the bottom Dunlop latex can be engineered for any firmness, but it is usually on the firmer side It may be used as a softer comfort layer or a firmer support core/base material The sediment in Dunlop latex pulls down the weight, making the material fairly bottom-heavy Talalay 1. Latex is whipped into a froth and injected into a mold 2. The mold is vacuum-sealed, causing the latex to expand to its full shape 3. Latex is frozen, which pushes carbon dioxide through the material and forms air pockets 4. Latex is baked, then removed from the mold and washed/dried Homogenous Talalay latex has a light, fluffy consistency that is uniform throughout the material Talalay latex tends to be airier and softer than Dunlop latex foam It is commonly used as a comfort layer material, but rarely used in the support core Talalay latex tends to be lighter due to its air pockets

Generally speaking, Dunlop latex tends to have a higher density than Talalay latex; this is one of the reasons why Dunlop latex is primarily used as a support core material.
When measuring density, latex falls into one of three categories: low, medium, or high. Density is also used to evaluate polyfoam and memory foam used in mattresses. However, density ranges for these materials vary considerably. The comparison table below lists normal density ranges for latex (both Dunlop and Talalay), polyfoam, and memory foam.

 Material Low-density Range Medium-density Range High-density Range Latex Less than 4.3 PCF 4.3 to 5.3 PCF More than 5.3 PCF Polyfoam Less than 1.5 PCF 1.5 PCF to 1.7 PCF More than 1.7 PCF Memory foam Less than 4 PCF 4 PCF to 5 PCF More than 5 PCF

It’s worth noting that most mattress brands offering latex beds do not disclose the density of individual latex layers. This is because firmness and indentation load deflection (ILD) are more commonly used to evaluate how a mattress feels for sleepers (see next section). This is not the case for polyfoam and memory foam mattress layers; brands frequently disclose density specs for these materials.

## Density vs. Firmness and ILD

Some mattress brands use the terms ‘density’ and ‘firmness’ interchangeably. However, this is technically inaccurate. While density is a weight/volume measurement used for individual mattress layers, ‘firmness’ refers to how soft or firm the bed feels as a whole. Firmness is assigned using a 1-10 scale, with 1 being softest and 10 being firmest. Most mattresses made today range from a 3, or ‘Soft,’ to an 8, or ‘Firm.’

Another firmness measurement is indentation load deflection, or ILD. ILD refers to the amount of weight needed to compress a certain material. To calculate ILD, place a metallic disk measuring 1 foot in diameter on a section of material measuring 4 inches thick. The ILD – expressed in numerals – is the amount of weight needed to compress that material by 25%.
The table below lists common firmness and ILD ranges for the latex used in today’s mattresses.

 Firmness Level 1-10 Rating Latex ILD Range Characteristics ‘Extra Soft’ 1-2 12 or lower The material conforms very closely to the sleeper’s body and sinks significantly ‘Soft’ 3 13 to 17 The material conforms closely and sinks to a noticeable degree ‘Medium Soft’ 4 18 to 22 Close conforming, but not as much sinking as softer materials ‘Medium’ 5 23 to 26 Moderate conforming with some sinking ‘Medium Firm’ 6 27 to 33 Moderate conforming, minimal sinking ‘Firm’ 7-8 34 to 38 Minimal conforming and little to no sinking ‘Extra Firm’ 9-10 39 or higher Very little conforming, typically no sinking whatsoever

Although density and firmness/ILD are separate measurements, there is some overlap between them. Denser latex layers are usually firmer and offer less conforming, while less dense layers will feel softer and conform more. It’s important to note that, while many brands do not disclose latex density specs, most provide firmness and/or ILD specs for their beds.

## Natural vs. Synthetic Latex

In addition to density and processing method, latex mattress shoppers should evaluate each bed based on how much natural and/or synthetic latex is used.

Natural latex primarily consists of the extract from rubber trees, though chemical-based cure packages are also used to generate the foamy material during processing; this is true of Dunlop and Talalay processing methods. Some brands advertise their mattresses as 100% organic, but this label is misleading. The standard certification for organic latex – known as the Global Organic Latex Standard (GOLS) – mandates  the material must contain at least 95% natural latex. Therefore, a ‘certified-organic latex mattress’ still contains at least trace amounts of petrochemical filler.

Synthetic latex typically contains little to no natural latex. The chief components are petrochemicals, such as styrene and butadiene, which are treated with emulsifying agents to reduce surface tension. The resulting material is very similar to natural/organic latex in terms of density and feel, but it tends to be less durable and trap body heat to a more noticeable degree. Synthetic latex is also much less eco-friendly than natural/organic latex.

Blended latex contains a combination of natural and synthetic latex. The ratio varies by material, but as a rule blended latex must contain at least 30% natural latex; otherwise it should be labeled as ‘synthetic.’ Some brands advertise blended latex as ‘natural latex,’ which is also misleading because the blended latex may primarily consist of synthetic components.

## How Does Latex Density Affect a Mattress?

The density of latex layers in a mattress can impact other aspects of the bed, as well. The table below breaks down some of these factors, including temperature neutrality, pain relief, and odor potential.

 Mattress Performance Factor Low-density Latex Rating Medium-density Latex Rating High-density Latex Rating Durability Good Low-density latex is less durable than its denser counterparts, but is still fairly durable and tends to last longer than mattress foams Good to Very Good Most mattresses with medium-density latex have an expected lifespan of seven and a half years or longer, which is above-average Very Good High-density latex is one of the most durable mattress materials available; expect a lifespan of at least eight years Conforming Poor to Fair Latex provides less overall conforming than memory foam; low-density latex is more likely to sink without contouring closely to the sleeper’s body Good Medium-density latex conforms to a noticeable extent, but those seeking a deep body hug should opt for higher-density latex and/or foam Good to Very Good High-density latex is the best latex option for sleepers who prefer close, consistent conforming Pain/pressure relief Fair to Good Most low-density latex layers alleviate some aches and pains, but those with chronic discomfort may experience minimal relief Good to Very Good Due to its decent conforming ability, medium-density latex offers consistent pain and pressure relief for most sleepers Good to Very Good Most sleepers find that medium- and high-density latex layers offer comparable levels of pain and pressure relief Temperature neutrality Good Low-density latex offers stronger air circulation, allowing mattresses with this material to sleep cooler than those with denser latex Good Medium-density latex may absorb some body heat, but most find it maintains a tolerable – if not perfectly comfortable – temperature Fair to Good High-density latex can easily trap heat; some mattress manufacturers aerate the material with holes for easier airflow Sex Good Latex is more responsive than foam, which makes it better for sex; low-density latex offers the most responsiveness Fair to Good Mattresses with medium-density latex are sufficiently springy for most couples Fair High-density latex is not particularly responsive, and may not be springy enough for some couples Motion isolation Good Due to its responsiveness, low-density latex minimizes most – but not necessarily all – motion transfer Good to Very Good Medium-density latex isolates motion transfer fairly well – but not to the same extent as memory foam Very Good High-density latex comes closest to memory foam in terms of absorbing and reducing motion transfer Noise potential Excellent Density does not appear to impact noise potential, as low-density latex is virtually silent when bearing weight Excellent Medium-density latex does not make any noise when bearing weight either Excellent High-density latex, like its less dense counterparts, does not make noise when bearing weight Odor potential Good Mattresses with low-density latex often emit rubbery off-gassing odors when new, but in most cases the smells will dissipate in a matter of days (if not hours) Fair to Good Denser latex produces more odor than less dense latex, but medium-density latex is not associated with excessively strong or long-lasting smells Poor to Fair High-density latex carries the highest odor potential; smells range from noticeably pungent to offensive and persistent Mattress weight Moderate to High Latex is an exceptionally heavy mattress material, but low-density latex is the lightest option; the average mattress weighs 90-105 lbs. High Mattresses with medium-density latex can be fairly heavy; the average weight is about 100-115 lbs. High Naturally, high-density latex is the heaviest of the three; the average mattress with high-density latex weighs 110-125 lbs. Average price Moderate Latex – natural/organic latex in particular – can drive up the price-point of a mattress, though some low-cost options are also available; expect to pay between \$900 to \$1,300 for a Queen size mattress Moderate to High Generally, the denser the latex layers, the higher the price; as a result, beds with medium-density latex have middle-of-the-road price-points – on average, \$1,200 to \$1,600 in a Queen size High Latex mattresses are among the most expensive beds on the market; models with high-density latex are usually the priciest and carry an average price-point of \$1,500 to \$2,000

## Choosing the Right Latex Density

Lastly, latex mattress shoppers should consider two personal factors when choosing a model: body weight and sleep position.

Lighter individuals (less than 130 pounds) typically prefer beds that are softer and less dense because they conform to their bodies more closely. This is especially true of side sleepers, who need extra cushioning below the shoulders and hips in order to align their spines and prevent pressure points from building up. A firmer, denser mattress may not conform closely enough for lighter people.

Heavier individuals (more than 230 pounds) are the opposite. Firmer beds are considered the ideal because they do not sink excessively, unlike softer, less dense mattresses. Back and stomach sleepers do not need extra cushioning beneath the shoulders and hips because their position naturally aligns the spine; rather, they require a supportive, even sleep surface that won’t sag beneath their heaviest areas. As a result, most back and stomach sleepers also prefer firmer beds. Those who weigh between 130 and 230 pounds typically prefer mattresses that combine soft body-contouring and firm surface support.

The table below lists the optimal density ranges for sleepers based on weight and position. Please note these ratings are highly subjective; every sleeper is different, and some may find that different density levels are better for them.

 Sleep Position Ideal Density for Lightweight People (Less than 130 lbs.) Ideal Density for Average Weight People (130-230 lbs.) Ideal Density for Heavyweight People (More than 230 lbs.) Side Low to Medium Medium Medium to High Back Low to Medium Medium to High High Stomach Medium Medium to High High

## Additional Tuck Resources

To learn more about mattresses and other sleep products made from latex, please visit the following Tuck.com pages.