Calculate 95th percentile bandwidth from sample readings in bps, Kbps, Mbps, or Gbps, using the standard billing discard-top-5% method.
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95th Percentile Bandwidth Formula
The calculator uses the common 95th percentile bandwidth billing method: sort all bandwidth samples from lowest to highest, discard the highest 5% of samples, then return the highest remaining value.
d = ceil(0.05*n)
i = n - d - 1
P95 = S_i
Result = P95_Mbps / U_out
- n = total number of numeric bandwidth samples entered
- d = number of highest samples discarded
- i = zero-based index of the 95th percentile value after sorting in ascending order
- Si = sorted bandwidth sample at index i
- P95 = 95th percentile bandwidth value
- P95Mbps = 95th percentile value converted to Mbps
- Uout = output unit conversion factor relative to Mbps
The bandwidth samples field accepts values separated by commas, spaces, or line breaks. The input unit is first converted to Mbps using decimal network units. The samples are then sorted from smallest to largest. The calculator removes the highest ceil(5% of n) samples and reports the largest remaining sample. The output unit dropdown converts that final Mbps value to bps, Kbps, Mbps, or Gbps.
Bandwidth Unit Conversion Factors
| Unit | Meaning | Equivalent in Mbps |
|---|---|---|
| bps | bits per second | 0.000001 Mbps |
| Kbps | kilobits per second | 0.001 Mbps |
| Mbps | megabits per second | 1 Mbps |
| Gbps | gigabits per second | 1000 Mbps |
Samples Discarded at the 95th Percentile
| Number of samples | Discarded samples | 95th percentile is taken from |
|---|---|---|
| 10 | 1 highest sample | 9th value in sorted order |
| 20 | 1 highest sample | 19th value in sorted order |
| 100 | 5 highest samples | 95th value in sorted order |
| 288 | 15 highest samples | 273rd value in sorted order |
Example Calculations
Example 1: Small Mbps sample set
Suppose you enter these samples in Mbps:
10, 12, 15, 20, 25, 30
There are 6 samples, so the discard count is:
d = ceil(0.05*6) = 1
After sorting, the highest sample, 30 Mbps, is discarded. The highest remaining value is 25 Mbps.
95th percentile bandwidth = 25 Mbps
Example 2: Output converted to Gbps
Suppose you enter these samples in Mbps:
800, 850, 900, 950, 1000, 1100, 1300, 2000
There are 8 samples, so the discard count is:
d = ceil(0.05*8) = 1
The highest sample, 2000 Mbps, is discarded. The highest remaining value is 1300 Mbps.
1300 Mbps / 1000 = 1.3 Gbps
95th percentile bandwidth = 1.3 Gbps
FAQ
What does 95th percentile bandwidth mean?
95th percentile bandwidth is a way to estimate sustained bandwidth usage while ignoring short traffic spikes. In this method, the top 5% of measured samples are discarded, and the next highest value is used as the result. This is commonly used for bandwidth billing and capacity review.
Why does the calculator discard the highest samples instead of averaging them?
The 95th percentile method is not an average. It is based on sorted samples. By removing the highest 5% of readings, brief spikes have less effect on the result, while regular high usage is still counted.
How many samples should you enter?
You need at least two numeric samples. For a more meaningful 95th percentile result, use samples collected at regular intervals over the period you want to measure, such as every 5 minutes across a day, week, or month.
