What is 99th Percentile response time? (2024)

I was making a dashboard in Grafana for our service when I came across the term 99th Percentile response time.

What is 99th Percentile response time? (2)

Example

Say, if the 99th Percentile response time is 100ms, then out of 100 requests, 1 request took the max response time of 100 ms.

How to think?

You log all the requests and their response time. Sort them in the ascending order of times they took to complete. For 95th percentile, take the (mean/max) of the bottom 5% of the times they took to complete. This value is your 95th percentile response time.

Why is this better?

Mean and median are not a very good metric to show outliers. Say at 9 AM in my service, a peak traffic comes which delays the response time. For that much time, the Nth percentile response time will shoot up a lot as compared to mean and median. 99th percentile is 30 times worse than the median. Also, in the distributed system, when we make an upstream request, it can create a lot of downstream requests. And if those downstream request hit a service with bad 99th percentile delays, then it’s pretty bad.

So this is a better metric to note down. We are seeing the worst case for bottom X percent. Seeing the outliers well which mean and median are not capable of measuring.

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What is 99th Percentile response time? (2024)

FAQs

What is 99th Percentile response time? ›

In a similar manner, the 99th percentile latency tells us the time in which 99% of the requests to the server will return a response. So for example, if the 99th percentile latency was 2000 ms, then 99% of the requests in our dataset of load testing results would respond in 2000 ms or less.

What is the 99th percentile timing? ›

Similarly, p99 response time means the response time of 99% of the requests is less than or equal to the p99 value. p99 - 99% of the requests will be equal to or faster than the p99 value. p90 - 90% of the requests will be equal to or faster than the p90 value.

What does it mean if your in the 99th percentile? ›

The 99th percentile is the highest percentile you can get. It means you are among the top scorers since you scored higher than 99% of the group who took the test. Only 1 in 100 the group scores in this range, so it places you at the very top of the pool.

What is the 99th percentile benchmark? ›

99th percetile means that your benchmark is better then 99% of all benchmarks witht eh same hardware. It really depends where it's used. In benchmark rating which rates you being in 99th percentile? That means you're in Top 1% of that hardware bracket.

What is 99 percentile in API? ›

This is also known as the “tail end” of the response time distribution. The 99th percentile response time refers to the response time that is slower than 99% of all requests. Similarly, this is the response time for the 99th slowest request out of 100 requests.

What is percentile in response time? ›

If the 50th percentile (median) of a response time is 500ms that means that 50% of my transactions are either as fast or faster than 500ms. If the 90th percentile of the same transaction is at 1000ms it means that 90% are as fast or faster and only 10% are slower.

How is 99th percentile calculated? ›

The idea of the 99th percentile is to take a population of data (say, a collection of measurements from a system) and sort them, then discard the worst 1% and look at the largest remaining value. The resulting value has two important properties: It's the largest value that occurs 99% of the time.

Is the 99th percentile the top 1%? ›

In such cases, the 99th percentile is typically the highest, representing the top 1 percent of data points, while the bottom 1 percent fall into the 0th percentile. One common way to calculate percentiles is to use index values for the data points in a set.

Is 99th percentile big? ›

In the 3rd percentile to below the 85th percentile is at a healthy weight. In the 85th percentile to the 97th percentile is overweight. Above the 97th percentile to the 99.9th percentile is obese. Above the 99th percentile is severely obese.

How many people get 1600 on SAT? ›

More often than not, a 1600 can only be achieved by answering every single question correctly. A 1600 is only achieved by around 300 test takers per year and makes you eligible and highly competitive for admission at every college.

Is 99th percentile a genius? ›

In simple words, this means there are a lot of "normies", a few geniuses, and a few intellectually disabled people in a standard population. If we apply the empirical rule to IQ distribution, we can say that 68% of people have an IQ between 85 and 115; 95% - between 70 and 130; and 99.7% - between 55 and 145.

What does it mean when the 99 percentile latency is 100ms? ›

Say, if the 99th Percentile response time is 100ms, then out of 100 requests, 1 request took the max response time of 100 ms.

What is 99th percentile on SAT? ›

SAT Score Percentiles Chart
SAT ScoreNationally-Representative PercentilePercentile Among Actual SAT Test Takers
160099+99+
14609997
14509996
14409896
87 more rows

What is a good API response time? ›

Just to have a number in mind, high-performing APIs are considered to have between 0.1 and 1 second average response time. At 2 seconds the delay is noticeable. At 5 seconds the delay is so significant that the users are starting to abandon the application/website.

What is 95th percentile write latency? ›

P95 latency, also known as the 95th percentile of latency, is a statistical measure used in computer network performance analysis. It essentially indicates that 95% of requests to a system were served faster than this value, while 5% took longer.

What is 95th and 99th percentile in performance testing? ›

P95 (95th percentile): P95 latency reveals that 95% of requests fall below the specified threshold. This metric gives you additional insights into user experience, allowing you to cater to a wider audience. P99 (99th percentile): The P99 metric indicates that 99% of requests are completed within the recorded latency.

Can you score 99 percentile in 2 months? ›

Q1. Can I score 99 percentile in 2 months for JEE Main? Ans: Yes, candidates can score 99 percentile if they give proper time to their preparation. Also, adopting right strategies and maintaining consistency is important during the last months preparation.

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