Calculator Inputs
Enter time-weighted noise intervals using one consistent duration unit.
Example Data Table
This example shows how different sound levels combine into one equivalent exposure value.
| Source | Sound Level (dB) | Duration (Minutes) | Comment |
|---|---|---|---|
| Press Area | 88 | 15 | Short but intense exposure period |
| Assembly Line | 82 | 30 | Longer moderate exposure period |
| Loading Zone | 90 | 10 | Highest measured interval in the sample |
| Control Room | 74 | 20 | Lower background level for comparison |
Example result: The sample intervals produce an equivalent noise level of about 85.18 dB.
Formula Used
The equivalent continuous noise level combines different sound levels into one time-weighted value:
Leq = 10 × log10 [ Σ(ti × 10^(Li/10)) / Σti ]
- Li = sound level for each interval in decibels.
- ti = duration for each interval in the same time unit.
- Σ = total of all intervals.
This method converts each decibel value into linear energy, weights it by time, sums the exposure, and converts the result back to decibels.
How to Use This Calculator
- Choose a duration unit such as seconds, minutes, or hours.
- Enter a label for each source or exposure interval.
- Input the measured sound level in decibels for every interval.
- Enter the matching duration for each level using the same unit.
- Add or remove rows until all exposures are listed.
- Press the calculate button to show the Leq result above the form.
- Review the detailed table to see which interval contributes the most energy.
- Use the CSV or PDF buttons to save the calculated summary.
Frequently Asked Questions
1) What does equivalent noise level mean?
Equivalent noise level, or Leq, is one steady sound level containing the same total acoustic energy as changing noise over the chosen time period.
2) Why is Leq different from a simple average?
Decibels are logarithmic, so loud intervals contribute much more energy than quiet ones. Leq accounts for that energy weighting, while a simple average does not.
3) Which duration unit should I use?
Use any unit you prefer, but keep every interval in the same unit. The result stays correct because the formula uses consistent relative durations.
4) Can I mix minutes and hours in one entry set?
Not directly. Convert all durations to one common unit first, then enter them together so the weighting stays accurate.
5) Do short loud events strongly affect Leq?
Yes. Even brief high-level events can raise Leq noticeably because sound energy increases rapidly with decibel level.
6) Is this useful for workplace and community studies?
Yes. Engineers often use Leq for occupational assessments, traffic analysis, environmental surveys, equipment studies, and general acoustic exposure reviews.
7) What happens if a duration is zero?
A zero duration adds no valid exposure time, so this calculator blocks it. Enter only positive durations for meaningful results.
8) What do the export buttons save?
They save the calculated summary and interval breakdown. CSV is useful for spreadsheets, while PDF gives a simple report format.