Stats Calculator Online
Time & Dates Calculators
Age, date differences, duration math, and military time. Free tools on Stats Calculator Online with formulas, how-to steps, similar calculator widgets, tidbits, and exportable reports.
- Age Calculator CalculatorExact age in years, months, and days
- Date Difference CalculatorDays between two dates
- Hours & Minutes CalculatorAdd or subtract durations
- Decimal to Time CalculatorConvert decimal hours to H:MM
- Time to Decimal CalculatorConvert H:MM to decimal hours
- Military Time CalculatorConvert between 12-hour and 24-hour time
- Day of the Week CalculatorFind weekday for a calendar date
- Work Hours CalculatorHours worked from start, end, and break
Tidbits from Stats Calculator Online
Tidbit
A p-value is not the probability H₀ is true
It is the probability of data at least as extreme as yours if H₀ were true. Pair it with an effect size and confidence interval.
P-value calculator →Need a path?
Not sure which test to run?
Start with the statistical test selector, then open the matching calculator with formulas and APA export.
Test selector →Remember
Correlation is not causation
Pearson r measures linear association. Plot the scatter first, and prefer Spearman when the relationship is monotonic but not linear.
Correlation tools →
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- One-Sample t-Test CalculatorHypothesis Testing · Test a sample mean against a hypothesized value
- Mean, Median, Mode CalculatorDescriptive Statistics · Calculate arithmetic mean, median, and mode
- Normal Distribution CalculatorProbability Distributions · PDF, CDF, and quantiles of the normal
- Simple Linear Regression CalculatorRegression Analysis · Fit y = a + bx with inference
- Chi-Square Independence CalculatorHypothesis Testing · Test association in contingency tables
- Sample Size & Power CalculatorHypothesis Testing · Plan sample size for desired power