Estimate an STC-style sound isolation rating from transmission loss values or a simple sound reduction value. This calculator shows estimated STC, isolation category, speech privacy level, average transmission loss, and calculation details.
Quick estimate mode:
Enter one sound reduction or transmission loss value. The calculator uses it as a rough STC-style estimate.
Frequency-band mode:
Enter multiple transmission loss values. The calculator estimates an STC-style value from the average, minimum, and band spread.
Speech privacy:
The calculator assigns a general speech privacy category based on the estimated STC rating.
An STC rating calculator helps estimate how well a wall, door, window, floor, ceiling, or partition may reduce airborne sound. It can be useful for apartments, offices, studios, classrooms, home theaters, bedrooms, and noise-control planning.
This is a simplified estimate. Official STC ratings require standardized lab or field testing and rating procedures.
Official STC ratings are based on transmission loss measurements across speech-related frequency bands. This calculator uses simplified estimating methods:
STC stands for Sound Transmission Class. It is a single-number rating used to describe how well a building assembly reduces airborne sound, especially speech-range sound.
No. Transmission loss is usually measured at specific frequencies. STC is a single-number rating based on a set of transmission loss measurements.
STC 40 to 50 is generally good for many walls and partitions. STC 50 or higher is commonly considered stronger isolation for speech privacy.
Sound can leak through gaps, doors, windows, vents, outlets, ceiling paths, floor paths, and framing connections around the main wall or partition.