Free research and form tools
Seven tools for the jobs researchers, students and form builders run into all the time: from sample size and questionnaire reliability to survey analysis and Iranian data. All are free, need no sign-up and calculate in your own browser.
Research and theses
- Sample size calculation (Cochran)Sample size with Cochran's formula for a known or unknown population, with your own confidence level and margin of error, and the calculation steps.
- Morgan tableThe full 90-row Krejcie and Morgan table and a calculator that gives the exact figure for any population size.
- Cronbach's alpha calculatorQuestionnaire reliability from Excel or SPSS data: raw and standardized alpha, each item's correlation, alpha if item deleted and a ready-made methods paragraph.
Survey analysis
Iranian forms and data
How these tools are built
- Every calculation runs in your browser. What you type or paste, from national IDs to questionnaire responses, is not sent to a server.
- Each tool shows its formula on its own page and displays the calculation steps, so you can verify the number and cite it in your report.
- The numbers are checked against references: the Morgan table row by row against the 1970 paper, and Cronbach's alpha against SPSS Reliability Analysis output.
- Persian digits, the «٬» separator and the «٫» decimal mark are accepted everywhere, and data can be copied straight from Excel.
Frequently asked questions
Do these tools cost anything?
No. All the tools are free and you don't need to sign up to use them.
Where does the data I enter go?
Nowhere. The calculations run in JavaScript in your browser, and what you type or paste is not sent to a server.
Do the results match SPSS?
Cronbach's alpha uses the same formula and the same listwise deletion as SPSS and gives the same number for the same data. The sample size calculators reproduce the published formula and table exactly.
Can I cite these tools in my thesis?
Cite the method, not the tool: for example "the sample size was determined with the Krejcie and Morgan (1970) table" or "reliability was assessed with Cronbach's alpha". Each tool's page gives the formula and reference for its method.
From calculation to data collection
Once your sample size and instrument are ready, build the questionnaire or survey in Porsino for free and take the responses out as Excel or SPSS.