On this page
Understanding Noise Reduction Ratings
Formula
The Noise Reduction Rating (NRR) on hearing protection labels does not equal the actual noise reduction you receive. OSHA recommends derating the NRR: subtract 7 and divide by 2 for the real-world reduction.
Noise above 85 dB can cause hearing damage. OSHA limits exposure to 85 dB for 8 hours, with halving for every 3 dB increase (88 dB = 4 hours, 91 dB = 2 hours, etc.).
Common use cases:
- Selecting adequate hearing protection
- Calculating safe work exposure times
- Meeting OSHA workplace safety requirements
Frequently Asked Questions
Was this calculator helpful?
People Also Use
BMI Calculator
Calculate your Body Mass Index (BMI) instantly with our free calculator. Enter your height and weight to find your BMI category and health range.
Kids BMI
Calculate your child's BMI and percentile ranking using age and sex-specific CDC growth charts for ages 2-20.
Calorie Calculator
Estimate your daily calorie needs for weight loss, maintenance, or gain based on age, sex, height, weight, and activity level.
BMR Calculator
Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation to find how many calories your body burns at rest.
TDEE Calculator
Calculate your Total Daily Energy Expenditure based on BMR and activity level to plan your diet and fitness goals.
Macro Calculator
Calculate your daily macronutrient targets for protein, carbs, and fat based on your calorie goal and diet type.
Calorie Deficit
Calculate your daily calorie deficit needed to reach your goal weight within your desired timeframe.
Weight Loss
Estimate how long it will take to reach your goal weight based on your TDEE and chosen weekly loss rate.