Math & Numbers
Estimate statistical power for one-sample mean or proportion tests using sample size, alpha, and expected effect
statistical-power-calculatorMath & Numbers
Calculate standard normal PDF, CDF, tail probability, two-tail probability, and central area from a z-score
standard-normal-calculatorMath & Numbers
Calculate sample and population standard deviation, variance, coefficient of variation, and sigma intervals
standard-deviation-calculatorMath & Numbers
Sum arithmetic series, geometric series, or a custom list of terms
sum-of-series-calculatorFinance
Calculate profit/loss for stock call and put options
stock-option-calculatorMath & Numbers
Calculate sum of numbers with partial sums, cumulative sums, and statistics
sum-calculatorMath & Numbers
Calculate statistical measures for numerical datasets including mean, median, mode, standard deviation, and more
statistics-calculatorFinance
Calculate stock trading profit or loss including buy/sell commissions and fees
stock-profit-calculatorMath & Numbers
Fit zero-order, first-order, and second-order rate equations to concentration-time data. Get reaction order, rate constant k, half-life t½, and R² goodness-of-fit.
reaction-rate-calculatorMath & Numbers
σ(n) = 2n ⟺ perfect. Factorization-based σ(n), proper-divisor sum, deficient/perfect/abundant classification, abundancy index, Euclid–Euler form. n ≤ 10¹².
perfect-number-checkerMath & Numbers
Smallest k with a^k ≡ 1 (mod n) via φ(n) reduction: power table, minimality proof, cyclic subgroup <a>, primitive-root and maximal-order flags.
order-of-element-mod-nMath & Numbers
Three-point PERT estimates: te and σ² per activity, critical path, expected project duration and variance, and normal completion probability for a target time.
pert-network-analyzer