How to use the likert scale summary calculator
- Choose the number of answer levels on your scale, from 3 to 7, and the size of the top and bottom box.
- Enter one line for each question: the question text, then the number of answers at each level, lowest level first, separated by commas.
- Read the overall mean, top box and net score, then the table with the mean, standard deviation, median, top and bottom box and net score for every question.
- Use the second table to see the share of answers at each level, and download the results as a CSV file.
Formula
n = sum of the counts for the question
mean = sum of (score x count) / n, with scores start, start + 1, ...
standard deviation = square root of sum of count x (score - mean) squared / (n - 1)
top box = answers in the highest b levels / n; bottom box = answers in the lowest b levels / n
net score = (top box - bottom box) x 100, in percentage points
The median is the middle answer when all answers are sorted. If the two middle answers are different levels it is halfway between them. To reverse a reverse-worded question, new mean = (lowest score + highest score) - old mean.
Three statements on a 5-point scale
"I find the tool easy to use" has counts 2, 3, 9, 21, 15, so n = 50 and the mean is (2 + 6 + 27 + 84 + 75) / 50 = 3.88. The top 2 box is (21 + 15) / 50 = 72.0 percent, the bottom 2 box is (2 + 3) / 50 = 10.0 percent, and the net score is +62.0.
Across the three statements there are 150 answers, with an overall mean of 3.99, a top 2 box of 75.3 percent and a net score of +67.3. The third statement has the best mean (4.20) and net score (+80.0).
Reading the numbers
A rating scale such as strongly disagree to strongly agree gives ordered answers. The mean treats the gaps between levels as equal, which is a common simplification. The top box, bottom box and net score avoid that by counting how many people fall at each end of the scale, and they are easy to compare between questions and between surveys.
Look at the shape as well as the average. Two questions can share a mean of 3.0 while one has everyone in the middle and the other has people split between the two ends. The second table of shares shows that difference. For a scale that asks how likely people are to recommend something, the NPS calculator uses its own cut points. For other lists of numbers, the descriptive statistics calculator goes further.
Comparing groups and checking sample size
This page summarizes the counts you enter. To test whether two groups of respondents rated a question differently, a rank-based method such as the Kruskal-Wallis test is more appropriate than comparing means. Small samples move a lot: ten answers can shift the mean by half a point with one respondent.
Keep the scale the same across questions you add together, and state what the levels meant when you share results.
Assumptions and limits
- Each count is a whole number of 0 or more, entered from the lowest level to the highest.
- Every question uses the same number of levels, chosen at the top of the page.
- The mean and standard deviation assume equal spacing between levels. The top box, bottom box and net score do not.
- Questions with no answers are refused. The overall row adds up the counts of all questions, so questions with more answers weigh more.
Frequently asked questions
What is a top 2 box score?
It is the share of answers in the two highest levels of the scale, such as agree and strongly agree on a 5-point scale. The bottom 2 box is the same for the two lowest levels.
How is the net score different from the NPS?
The net score here is the top box minus the bottom box for the scale you chose. The Net Promoter Score uses a 0 to 10 question and fixed groups of promoters and detractors.
How do I handle a reverse-worded question?
Flip it by hand before comparing: the new mean is the lowest score plus the highest score minus the old mean. On a 1 to 5 scale a mean of 2.0 becomes 4.0.
My comma-separated questions contain commas. Is that a problem?
No. The last numbers on each line are read as the counts, and everything before them is the question, commas included. Put the counts last.