Mattress sagging is a common problem that affects sleep quality and can cause back pain.
For minor sagging, try rotating your mattress 180 degrees (head to foot) every 3 months to distribute wear evenly.
Add a mattress topper (2-4 inches of memory foam or latex) to provide additional support over sagging areas.
Place plywood between the mattress and foundation to create a firmer, more even surface.
Check your foundation—broken slats or worn box springs can cause mattress sagging.
If sagging exceeds 1.5 inches or causes pain, it is time to replace the mattress. Many warranties cover sagging over 1 inch.
Before attempting fixes, check your warranty. Many mattress warranties cover sagging over 0.75 to 1.5 inches (depending on the brand). Document the sag with photos and measurements — placing a straight edge across the mattress surface and measuring the gap can provide clear evidence.
A quality mattress topper (3-4 inches of high-density memory foam or latex) can extend the life of a sagging mattress by 1-2 years. This buys time while you research and budget for a replacement. Choose a topper density of at least 4 lb/ft³ for meaningful support.
The root cause of sagging often lies in the foundation, not the mattress itself. A broken slat, worn box spring, or uneven surface beneath the mattress can create localized pressure points that cause premature wear. Always inspect the foundation before blaming the mattress.