Free Tools

Calculators and converters — no sign-up, instant results.

Statistics Tools

t-tests, ANOVA, chi-square, correlation, regression, power analysis and effect sizes — free online calculators with plain-language interpretation, automatic assumption checks and APA 7 reporting.

Independent Samples t-Test Calculator

Compare two group means with Welch or Student t-test, effect size, confidence interval and automatic assumption checks.

Paired Samples t-Test Calculator

Test before/after or matched-pair differences with effect size, confidence interval and normality check.

One-Way ANOVA Calculator (+ Tukey HSD)

Compare three or more group means with the full ANOVA table, effect sizes and Tukey HSD post-hoc comparisons.

Two-Way ANOVA Calculator

Test two factors and their interaction with the complete ANOVA table and partial eta squared effect sizes.

Chi-Square Test Calculator

Test of independence for contingency tables and goodness-of-fit test, with Cramér's V and expected counts.

Correlation Calculator (Pearson & Spearman)

Pearson r and Spearman rho together, with significance test, confidence interval and normality check.

Simple Linear Regression Calculator

Fit y = a + bx with coefficient table, R², F-test, confidence intervals and residual normality check.

Power Analysis Calculator: t-Test

A priori sample size and post-hoc power for t-tests — G*Power parameters (d, α, power) in the browser.

Power Analysis Calculator: One-Way ANOVA

Sample size and power for one-way ANOVA from Cohen's f — a browser-based G*Power alternative.

Power Analysis Calculator: Two Proportions

Sample size and power for comparing two proportions (A/B tests, clinical rates) via Cohen's h.

Effect Size Converter (d, r, f, η², OR)

Convert between Cohen's d, r, Cohen's f, eta squared and odds ratio; includes Hedges' g and CLES.

Descriptive Statistics Calculator

Mean, SD, median, quartiles, skewness, kurtosis, SEM and 95% CI — with Shapiro-Wilk normality test.

P-value Calculator

Convert a z, t, chi-square or F test statistic into its exact p-value — one- or two-tailed, with a plain-language verdict.

Confidence Interval Calculator

90/95/99% confidence interval for a mean (t or z) or a proportion — from summary statistics, with margin of error and critical value.

Z-Score Calculator

Standardize a value (x, mean, SD) or enter z directly — percentile rank and left-, right- and two-tailed probabilities included.

Standard Deviation Calculator

Sample (n−1) and population (n) standard deviation and variance in one shot — with SEM, coefficient of variation and sum of squares.

Mann-Whitney U Test Calculator

Non-parametric comparison of two independent groups — U, z and p with tie correction, plus the rank-based effect size r.

Wilcoxon Signed-Rank Test Calculator

Non-parametric paired comparison (before/after) — V, z and p with tie correction; zero differences handled the standard way.

Kruskal-Wallis H Test Calculator

Non-parametric comparison of 3+ independent groups — tie-corrected H, df, p and the effect size ε², with group medians.

Cronbach's Alpha Calculator

Scale reliability from an item-response matrix: raw and standardized α, mean inter-item correlation and alpha-if-item-deleted.

Binomial Probability Calculator

P(X = k) plus all cumulative probabilities (≤, ≥, <, >) for n trials with success probability p — with mean and SD.

Permutation & Combination Calculator

C(n, k) and P(n, k) side by side, with factorials — exact integers up to 15 digits, scientific notation beyond.

Finance & Business Tools

Gross-to-net salary, severance pay, VAT, profit margin, loan installments, ROI and freelance withholding — instant, free calculators with up-to-date 2026 parameters.

Gross to Net Salary Calculator (Türkiye 2026)

Gross-net and net-gross salary for Türkiye with a full 12-month tax breakdown and employer cost.

Severance Pay Calculator (Türkiye 2026)

Turkish severance and notice pay from your employment dates, with the current 2026 ceiling.

VAT Calculator

Add or extract VAT with multi-country rate presets and reverse-charge withholding.

Profit Margin Calculator

Margin, markup and profit from cost and price — or the right price from a target margin.

Loan Payment Calculator

Fixed monthly installment, total cost and a full amortization schedule.

ROI Calculator

Return on investment and annualized return (CAGR) from cost and final value.

Currency Converter

Convert currencies with daily rates — or enter your own rate when offline.

Freelance Withholding Calculator (Türkiye)

Turkish freelance invoices: 20% withholding, 20% VAT and the amount you collect.

Compound Interest Calculator

Future value of savings with compound interest and regular contributions, with a full interest breakdown.

Percentage Increase Calculator

Percent increase or decrease between two values, or apply a percentage to a number.

Hourly to Salary Calculator

Convert an hourly wage to weekly, monthly and annual pay — with per-country workweek presets.

Inflation Calculator (Türkiye)

What an amount from one year is worth in another, using official Turkish CPI (TÜİK) data.

Discount Calculator

Sale price and savings from a discount percentage — including stacked double discounts.

Savings Goal Calculator

The monthly amount you need to save to reach a target, with interest working for you.

Break-Even Point Calculator

Units and revenue needed to cover fixed costs, with contribution margin and target profit.

Education & Academic Tools

GPA, final grade, weighted average, word count, readability and APA 7 citations — instant, free, no sign-up required.

GPA Calculator

Calculate your weighted GPA in US 4.0, Turkish, German and French grading systems.

Final Grade Calculator

Find the score you need on the final exam to reach your target course grade.

Weighted Grade Calculator

Combine homework, quizzes and exams by their weights into one course average.

Word Counter

Count words, characters, sentences and paragraphs, with reading and speaking time.

Readability Checker

Score your text with Flesch, Fernández Huerta or Wiener readability formulas.

APA Citation Generator

Create APA 7 references and in-text citations for books, journal articles and web pages.

Health & Fitness

Calorie, BMR, body fat, ideal weight, water intake, macro and body surface area calculators — free, instant, no sign-up. For information only, not medical advice.