How to Measure Mattress Sag for Warranty

Key Takeaways

  • Proper measurement is crucial for warranty coverage: Accurately measuring mattress sag ensures eligibility for warranty coverage. Following the outlined steps, including identifying sagging areas and calculating sag depth using a straight edge, provides essential documentation for your claim, ensuring timely resolution and maintaining your mattress investment.
  • Documentation is essential: Keeping detailed records of sag measurements, including location and depth, serves as crucial evidence when filing a warranty claim. Thorough documentation expedites the claims process with the manufacturer or retailer, ensuring efficient resolution of any sagging issues.
  • Understand warranty terms: Familiarize yourself with your mattress warranty’s terms and conditions, including coverage limits, exclusions, and required documentation. Pay attention to thresholds for excessive sagging and specific claim filing requirements to ensure your claim meets the criteria and avoids delays.

Mattress sagging is a common issue that can affect the comfort and support of your bed over time.

Many mattress warranties cover excessive sagging, but to make a warranty claim, you need to accurately measure the degree of sag.

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In this guide, we’ll walk you through the steps to properly measure mattress sag for warranty purposes, ensuring you get the most out of your mattress investment.

Steps to Measure Mattress Sag:

Below are the main steps to measure sag:

a. Prepare the Mattress:

Remove all bedding, including sheets, blankets, and mattress protectors, to expose the surface of the mattress.

Ensure the room is well-lit and free from any obstructions that may hinder accurate measurements.

b. Identify the Sagging Areas:

Visually inspect the mattress to identify the areas where sagging is most prominent.

These are typically the areas where your body weight is concentrated when you sleep.

c. Use a Straight Edge:

Place a straight edge, such as a ruler or yardstick, across the width of the mattress, perpendicular to the sagging area.

Ensure the straight edge is long enough to cover the width of the mattress and extends beyond the depressed area.

d. Measure the Sag Depth:

Using a tape measure or ruler, measure the distance between the straight edge and the bottom of the sagging area.

Record this measurement in inches or centimeters.

Tips for Accurate Measurement:

  • Use a sturdy, flat surface as a reference point for placing the straight edge to ensure consistent measurements.
  • Measure sagging when the mattress is in its usual sleeping position, with weight distributed evenly across the surface.
  • Take measurements at different times of the day and from various angles to capture any variations in sag depth.

e. Repeat for Multiple Points:

Repeat the measurement process for each sagging area across the mattress, including both sides and the middle. Take multiple measurements to ensure accuracy and consistency.

f. Calculate the Average Sag Depth:

Once you have measured sagging at multiple points, calculate the average sag depth by adding all measurements together and dividing by the total number of measurements taken.

This will provide an overall indication of the mattress’s level of sagging.

g. Document the Measurements:

When measuring mattress sag for warranty claims, it’s essential to document your findings accurately to support your claim effectively.

Here are some key considerations for documenting mattress sag:

  1. Record Measurements: Keep a detailed record of the sagging areas on your mattress, including the depth of sag measured in inches or centimeters. Note the location of each sagging area, such as the middle or sides of the mattress.
  2. Take Photographs: Capture visual evidence of the sagging areas by taking clear photographs or videos. Ensure that the images accurately depict the extent of the sagging and provide context for the measurements taken.

When filing a warranty claim for a sagging mattress, it’s helpful to include the following types of photos to support your claim:

  1. Overall View: Take a photo of the entire mattress from a distance, showing its general appearance and any visible sagging areas. This provides context and helps assess the extent of the sag across the mattress surface.
  2. Close-Up of Sagging Areas: Capture close-up shots of the specific areas where sagging is most prominent. Focus on indentations or depressions in the mattress surface, highlighting the depth and severity of the sag.
  3. Measurement Photos: Take photos of the sagging areas with a straight edge placed across the mattress perpendicular to the sagging area. This demonstrates the depth of sag measured using a ruler or tape measure, providing quantitative evidence of the sag.
  4. Multiple Angles: Photograph sagging areas from different angles and perspectives to provide a comprehensive view. This helps ensure that all sagging areas are documented thoroughly and accurately.
  5. Date Stamp: If possible, enable the date stamp feature on your camera or include a timestamp in the photo metadata. This helps establish the timeline of the sagging and verifies that the photos were taken within the warranty period.
  6. Organize Your Documents: Organize your measurement records and photographs in a designated file or folder for easy reference. Store digital copies of documentation securely to ensure accessibility when filing a warranty claim.
  7. Reassess Periodically: Periodically reassess the condition of your mattress and update your documentation as needed. Regular monitoring allows you to track any changes in sagging over time and provides up-to-date evidence for warranty claims.
  8. Notify Manufacturer or Retailer: If you discover excessive sagging on your mattress, notify the manufacturer or retailer promptly, even if you’re not yet ready to file a warranty claim. Early notification allows them to document the issue and provide guidance on next steps.
  9. Follow Warranty Procedures: Adhere to the warranty procedures outlined by the manufacturer or retailer when filing a claim for mattress sag. Provide the required documentation and follow any instructions for submitting the claim to ensure a smooth and timely resolution.
  10. Retain Documentation: Retain documentation for mattress sag warranty claims for the duration of the warranty period and beyond, if possible. Keeping comprehensive records ensures that you have the necessary evidence to support a warranty claim, even if the issue arises later.

Understanding Warranty Coverage:

Most mattress warranties cover sagging that exceeds a certain threshold, typically ranging from 0.75 inches to 1.5 inches, depending on the manufacturer and mattress model.

Before filing a warranty claim, review the terms and conditions of your mattress warranty to understand the coverage limits, exclusions, and required documentation.

Here are key points to understand the mattress warranty coverage in detail:

a. Coverage Period:

Most mattress warranties specify a coverage period, typically ranging from 5 to 20 years, during which the manufacturer will repair or replace the mattress if it exhibits defects covered under the warranty.

Be sure to review the duration of coverage to understand the timeframe within which you can file a warranty claim.

b. Types of Coverage:

Warranty coverage may vary depending on the type of defects included. Common types of coverage include:

Sagging: Many warranties cover excessive sagging, typically defined as indentations greater than a specified depth (e.g., 1.5 inches). Sagging can affect the comfort and support of the mattress and is a common issue covered under warranties.

Structural Defects: Warranties often cover structural defects such as broken or protruding coils, loose seams, or sagging beyond a certain threshold. These defects can impact the integrity and performance of the mattress and may qualify for warranty coverage.

Workmanship and Materials: Some warranties provide coverage for defects in workmanship or materials, such as manufacturing flaws or issues with the mattress components. Be sure to review the warranty terms to understand the scope of coverage for workmanship and materials.

c. Exclusions:

It’s important to be aware of any exclusions or limitations specified in the warranty. Common exclusions may include:

Damage caused by misuse, abuse, or improper care.

Normal wear and tear, including minor body impressions or changes in mattress firmness over time.

Damage resulting from inadequate support, such as using an improper foundation or bed frame.

d. Prorated vs. Non-Prorated Coverage:

Mattress warranties may offer either prorated or non-prorated coverage for repair or replacement.

Prorated Coverage: With prorated coverage, the manufacturer may require the customer to pay a percentage of the original mattress price for repair or replacement, depending on the length of time the mattress has been in use.

Non-Prorated Coverage: Non-prorated coverage typically provides full repair or replacement at no additional cost within the warranty period. However, certain conditions or limitations may apply, so it’s essential to review the terms carefully.


Why is it important to measure mattress sag for warranty?

Measuring mattress sag is crucial for determining whether your mattress qualifies for warranty coverage. Many mattress warranties include provisions for excessive sagging, but accurate measurements are necessary to validate a warranty claim.

How often should I measure mattress sag for warranty purposes?

It's a good idea to measure mattress sag periodically, especially if you notice changes in the comfort or support of your mattress. Regular measurements can help track any changes in sagging over time and provide documentation for warranty claims if needed.

What tools do I need to measure mattress sag accurately?

To measure mattress sag, you'll need a straight edge (such as a ruler or yardstick) and a tape measure or ruler to measure the depth of the sagging areas. Additionally, good lighting and a flat surface are essential for accurate measurements.

At what point does mattress sag become excessive for warranty coverage?

The threshold for excessive sagging varies depending on the manufacturer and mattress model. Most mattress warranties specify a maximum allowable sag depth, typically ranging from 0.75 inches to 1.5 inches. If the sagging exceeds this threshold, it may qualify for warranty coverage.

How do I identify sagging areas on my mattress?

Sagging areas are typically visible as indentations or depressions on the surface of the mattress, especially in areas where your body weight is concentrated when you sleep. These areas may feel softer or less supportive compared to the rest of the mattress.

Can I measure the mattress sag myself, or should I seek professional assistance?

You can measure mattress sag yourself using the steps outlined in the warranty guidelines. However, if you're unsure about the accuracy of your measurements or have difficulty accessing certain areas of the mattress, you may consider seeking professional assistance to ensure precise measurements.

What should I do if my mattress exhibits excessive sagging within the warranty period?

If your mattress develops excessive sagging within the warranty period, document the sagging areas and their depth according to the manufacturer's guidelines. Then, contact the mattress manufacturer or retailer to initiate a warranty claim and request a replacement or repair.

Will measuring mattress sag void the warranty?

No, measuring mattress sag for warranty purposes should not void the warranty. In fact, accurate measurements are necessary to validate a warranty claim and determine whether the mattress meets the criteria for coverage.

What if my mattress warranty does not cover sagging?

If your mattress warranty does not cover sagging or has specific exclusions related to sagging issues, you may explore other options such as mattress toppers or pads to improve comfort and support. Additionally, consider consulting with the manufacturer or retailer for further assistance or recommendations.


Measuring mattress sag for warranty claims is a straightforward process that requires careful attention to detail and accurate measurements.

By following the steps outlined in this guide, you can assess the extent of sagging in your mattress and determine whether it meets the criteria for warranty coverage.

If your mattress exhibits excessive sagging within the warranty period, contact the manufacturer or retailer promptly to initiate the claims process and seek a replacement or repair.

Investing time in proper measurement ensures you receive the support and comfort you deserve from your mattress for years to come.

This article is for informational purposes and should not replace advice from your doctor or other medical professional.

Sarah Anderson, Certified Sleep Science Coach Sarah Anderson

Sarah Anderson is a sleep, health, and wellness writer and product reviewer. She has written articles on changing and improving your sleep schedule, choosing the right mattress for chronic pain conditions, and finding the best pillow for you. Sarah Anderson has her Bachelor of Arts degree from Arizona State University in Journalism and Mass Communications. Prior to working for Zoma, she wrote for a variety of news publications. Sarah's work has been featured on Bustle, PureWow, and other publications.

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