PaperSurvey.io

Survey & Statistics Calculators

A free suite of 62 calculators for designing surveys and analysing results, from sample size and margin of error to reliability, significance tests and scale scoring. Everything runs in your browser, so nothing you type is sent to a server, and there is no sign-up.

The formulas mirror the analytics engine inside PaperSurvey.io, so the numbers you get here match what you would see after scanning and processing a real paper or web survey. Every calculator can be embedded on your own site with a single line of code.

Built into PaperSurvey.io

Skip the copy-paste. Scan your paper or web surveys and PaperSurvey computes these metrics automatically on your real data, ready to export to Excel, SPSS and R. See how

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Survey methodology

Plan and size a survey, and measure how precise your results really are. Work out sample sizes, margins of error, confidence intervals and response rates before and after you collect data.

Margin of Error CalculatorFree margin of error calculator. Enter your sample size, population and confidence level to find the margin of error for your survey results.Sample Size CalculatorFree sample size calculator. Find how many survey responses you need for a given confidence level and margin of error, with optional population correction.Confidence Interval Calculator (Proportion)Calculate the confidence interval for a survey proportion. Enter sample size, the percentage who chose an answer and a confidence level.Confidence Interval Calculator (Mean)Calculate the confidence interval for a mean using the t distribution. Enter the sample mean, standard deviation, sample size and confidence level.Survey Response Rate CalculatorCalculate your survey response rate. Enter the number of responses received and the number of people invited to get the response rate as a percentage.Survey Completion Rate CalculatorCalculate your survey completion rate: the share of people who started your survey and reached the end.Sample Size Calculator for a MeanFind the sample size needed to estimate a mean within a given margin of error, based on the expected standard deviation and confidence level.A/B Test Sample Size CalculatorCalculate the sample size per group needed to detect a difference between two conversion or response rates, given confidence and power.Design Effect & Effective Sample Size CalculatorFree design effect calculator. Enter your cluster size and intra-cluster correlation to get the design effect and effective sample size.Finite Population Correction CalculatorFree finite population correction calculator. Find the factor that shrinks your margin of error when the sample is a large share of the population.

Customer experience

Turn raw feedback into the metrics teams actually track. Calculate NPS, CSAT, CES, churn and average ratings from your survey responses.

NPS Calculator (Net Promoter Score)Free Net Promoter Score (NPS) calculator. Enter your promoters, passives and detractors to get your NPS from -100 to +100.CSAT Calculator (Customer Satisfaction)Free CSAT calculator. Enter the number of satisfied respondents and total respondents to get your customer satisfaction score.CES Calculator (Customer Effort Score)Free Customer Effort Score (CES) calculator. Paste your effort ratings to get the average effort score.Weighted Average CalculatorFree weighted average calculator. Enter values and their weights to compute the weighted mean.Churn Rate CalculatorFree churn rate calculator. Enter customers lost and customers at the start of the period to get churn and retention rates.Average Star Rating CalculatorFree average star rating calculator. Enter how many 1 to 5 star ratings you received to get the weighted average rating.NPS Confidence Interval CalculatorFree NPS confidence interval calculator. Enter your promoter, passive and detractor counts to get the margin of error on your Net Promoter Score.

Descriptive statistics

Summarise a set of numbers at a glance: central tendency (mean, median, mode), spread (standard deviation, variance, percentiles) and the shape of the distribution.

Mean, Median and Mode CalculatorFree mean, median, mode and range calculator. Paste your numbers to get all the measures of central tendency at once.Standard Deviation CalculatorFree standard deviation calculator for sample and population data. Paste your numbers to get the standard deviation, variance and mean.Variance CalculatorFree variance calculator for sample and population data. Paste your numbers to get the variance.Percentile & Quartile CalculatorFree percentile and quartile calculator. Paste your data and choose a percentile to get its value, plus Q1, median, Q3 and the IQR.Z-Score CalculatorFree z-score calculator. Enter a value, the mean and the standard deviation to get the z-score and its percentile rank.Coefficient of Variation CalculatorFree coefficient of variation calculator. Paste your data to get the CV, a standardised measure of spread relative to the mean.Standard Error CalculatorFree standard error of the mean (SEM) calculator. Paste your data to get the standard error, mean and standard deviation.Geometric Mean CalculatorFree geometric mean calculator. Paste positive numbers to get their geometric mean.Harmonic Mean CalculatorFree harmonic mean calculator. Paste your numbers to get the harmonic mean.Skewness and Kurtosis CalculatorFree skewness and kurtosis calculator. Paste your data to measure the asymmetry and tailedness of the distribution.Outlier CalculatorFree outlier calculator using the 1.5 × IQR rule. Paste your data to detect outliers and see the lower and upper fences.

Inferential statistics

Go beyond description and test whether the differences and relationships in your data are statistically significant, with proper p-values from the t, chi-square, F and normal distributions.

Chi-Square Test CalculatorFree chi-square test of independence calculator. Paste a contingency table to get the chi-square statistic, degrees of freedom, p-value and Cramér’s V.Cramér's V CalculatorFree Cramér's V calculator. Paste a contingency table to measure the strength of association between two categorical variables.T-Test Calculator (Two Samples)Free two-sample t-test calculator using Welch's method. Paste two groups of numbers to get the t statistic, degrees of freedom, p-value and Cohen's d.One-Way ANOVA CalculatorFree one-way ANOVA calculator. Paste each group on its own line to get the F statistic, degrees of freedom and p-value.Correlation Calculator (Pearson r)Free Pearson correlation calculator. Paste paired X and Y values to get the correlation coefficient r and R².Linear Regression CalculatorFree simple linear regression calculator. Paste paired X and Y values to get the slope, intercept, R² and the regression equation.P-Value CalculatorFree p-value calculator. Convert a z, t, chi-square or F test statistic into a p-value.One-Sample T-Test CalculatorFree one-sample t-test calculator. Paste your data and a hypothesised mean to get the t statistic, degrees of freedom and p-value.Paired T-Test CalculatorFree paired t-test calculator. Paste before and after values to test whether the mean difference is significant.Cohen's d Calculator (Effect Size)Free Cohen's d effect size calculator. Paste two groups of values to measure how large the difference between their means is.Odds Ratio CalculatorFree odds ratio calculator from a 2×2 table, with relative risk and a 95% confidence interval.Fisher's Exact Test CalculatorFree Fisher's exact test calculator for a 2×2 table. Ideal for small samples where the chi-square test is unreliable.Spearman Correlation CalculatorFree Spearman's rank correlation calculator. Paste paired X and Y values to get the rank correlation coefficient rho.Point-Biserial Correlation CalculatorFree point-biserial correlation calculator. Measure the relationship between a two-group variable and a continuous one, with p-value.Compare Two Correlations CalculatorFree calculator to test whether two independent correlations differ significantly, using the Fisher r-to-z transformation.Confidence Interval for a Correlation CalculatorFree calculator for the confidence interval of a correlation coefficient, using the Fisher r-to-z transformation.Cohen's h CalculatorFree Cohen's h calculator. Enter two proportions to get the effect size for the difference between them, using the arcsine transformation.Number Needed to Treat (NNT) CalculatorFree number needed to treat calculator. Enter control and treatment event rates to get the NNT and the absolute risk reduction.Relative Risk CalculatorFree relative risk calculator. Enter a 2x2 table of exposure and outcome to get the risk ratio and its 95% confidence interval.

Education & assessment

Score and grade tests, then analyse their quality: item difficulty, discrimination, reliability (Cronbach’s alpha, KR-20) and inter-rater agreement.

Test Grade CalculatorFree test grade calculator. Enter points earned and total points to get the percentage score.Item Difficulty CalculatorFree item difficulty calculator for test analysis. Enter how many students answered a question correctly to get the difficulty index.Discrimination Index CalculatorFree item discrimination index calculator using the upper/lower 27% method. Paste total scores and whether each student got the item right.Cronbach's Alpha CalculatorFree Cronbach's alpha calculator. Paste your item response matrix (rows = respondents, columns = items) to measure internal consistency reliability.Pass Rate CalculatorFree pass rate calculator. Paste the scores, set the maximum score and passing threshold to get the percentage of students who passed.Weighted Grade CalculatorFree weighted grade calculator. Enter your component scores and their weights to get your overall weighted grade.KR-20 CalculatorFree KR-20 calculator. Paste a matrix of correct (1) and incorrect (0) responses to measure test reliability for dichotomous items.Standard Error of Measurement CalculatorFree standard error of measurement calculator. Enter the standard deviation and reliability to get the SEM of a test.Cohen's Kappa CalculatorFree Cohen's kappa calculator. Paste the agreement matrix between two raters to measure inter-rater agreement beyond chance.Fleiss' Kappa CalculatorFree Fleiss' kappa calculator. Paste your rating counts to measure agreement between three or more raters, corrected for chance.Krippendorff's Alpha CalculatorFree Krippendorff's alpha calculator. Paste the codes each coder assigned to measure inter-coder reliability, with support for missing values.Intraclass Correlation (ICC) CalculatorFree intraclass correlation calculator. Paste a matrix of subject ratings by rater to get ICC(2,1) and ICC(2,k) for inter-rater reliability.Spearman-Brown Prophecy CalculatorFree Spearman-Brown prophecy calculator. Predict how a test’s reliability changes when you add or remove items.KR-21 CalculatorFree KR-21 calculator. Enter the number of items, mean score and variance to estimate test reliability without the full response matrix.

About these calculators

Each tool gives you the result instantly as you type, along with a plain-language explanation of the formula and what the numbers mean. They cover the full survey workflow: work out how many responses you need with the sample size calculator, check how precise your results are with the margin of error calculator, score customer feedback with the NPS and CSAT calculators, and run proper significance tests like the chi-square test, t-test and ANOVA.

From paper to results

Most of these statistics are things you would normally compute after collecting a survey. PaperSurvey.io scans paper questionnaires and exam sheets into clean digital data with high-accuracy checkbox recognition and AI handwriting recognition, then lets you export to Excel, CSV, SPSS, R and Google Sheets, so the raw numbers for these calculators are ready without any manual data entry.

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