Tools - LeCursos
Compound interest calculator with contributions
Calculate compound interest with monthly contributions. See the final amount, how much of it is your own money and how much is interest, period by period.
Descriptive statistics calculator
Paste a series of numbers and get mean, median, mode, standard deviation, variance, quartiles and a box plot. Sample and population shown side by side.
Which statistical test should I use
Answer a few questions about your data and your question, and find the statistical test that usually fits, along with the assumption you have to check first.
Interest rate converter
Turn a rate for one period into the equivalent rate for any other, and see how far the compounded yearly rate sits from the one that is merely multiplied.
Sample size calculator
How many people a survey needs for the margin of error and confidence you want, and why the size of the population barely changes the answer.
Break even point calculator
How much you have to sell to stop losing money, in units and in revenue, with the version that ignores depreciation and the one that includes the profit you want.
Fixed instalment versus constant amortisation
Compare the two amortisation schedules of the same loan, see the instalment where one overtakes the other, and find out which is cheaper once the calendar is taken into account.
Net present value, internal rate and payback
Work out what a project is worth today, find every rate that brings it to zero rather than just the first one, and see the payback with and without discounting.
Simple linear regression
Paste your points and get the line, the slope, the correlation and the plot, with the four sets that show why the numbers alone are not enough.
Number base converter and two's complement
Convert between binary, octal, decimal and hexadecimal, and see the same bits read as a positive number and as a negative one, with the negation worked out step by step.
Economic order quantity
Find the lot size that costs the least over a year, and see how little it costs to be wrong about it, which is the part that actually changes what you do.
Hypothesis test calculator with z and t
Test one average against a reference value and get the p value, the critical value, the range the true average is compatible with, and the conclusion written out in plain words.
Process capability calculator, Cp and Cpk
Work out the capability of a process against its specification limits, the defect rate that follows, and how much of it is spread and how much is simply sitting off centre.
Depreciation calculator, three methods side by side
Straight line, sum of the years and declining balance in one table, with the total they share and what the timing of the tax saving is actually worth.
Reorder point and safety stock calculator
Work out when to place the next order, how much safety stock the service level you want really costs, and whether your uncertainty comes from the demand or from the supplier.
X-bar and R control chart calculator
Paste your subgroups and get both control charts with their limits, the short-term standard deviation the ranges imply, and a plain answer on whether the process is stable.
ABC curve and Pareto classification of items
Paste your list and get the ABC classes, the cumulative curve and, before anything else, whether your curve is steep enough for the classification to be worth the trouble at all.
Invoice discounting: the rate you were quoted and the rate you pay
Work out what advancing an invoice really costs per month and per year, why the quoted rate is never the rate you pay, and why the same fixed fee hurts most on the shortest terms.
Odds converter: decimal, fractional, American, and the margin inside them
Turn one price into every other format and read the implied probability, then add up a whole market to see the house margin that no single price shows.
Big-O growth: what each complexity class actually costs
See the operations and the running time behind each complexity class, what happens when the input doubles, and the exact size where a heavier constant stops mattering.
Kelly stake, the fraction, and where the formula turns against you
Work out the stake the Kelly formula asks for, how much of the growth a fraction of it keeps, and the exact point past which betting more turns the growth negative.
Multiple bets: the payout multiplies and so does the margin
See what a multiple really pays, how unlikely the whole ticket is, and how the house cut compounds once per leg instead of being charged a single time.
Guaranteed return: when it exists, and why it almost never does
Check whether covering every outcome pays whatever happens, how the money has to be split, and the exact price at which the chance begins to exist at all.
Normal, binomial and Poisson, and what swapping one for another costs
Work out exact probabilities for a count and for a normal curve, and see how far the usual approximations land from the exact answer.