Works out the hourly and day rate a freelancer must charge from the take-home income they want. Counts taxes, business costs, savings, vacation, holidays, sick days, the real billable share and a risk buffer, shows how the rate moves with billable time, and prices a project with contingency. Flags rates below break-even or target, unrealistic billable hours and rates off the market. Includes a stdlib Python calculator with --self-test.
For cafes, restaurants, bakeries, and food trucks: turns supplier prices, yields, and recipes into exact cost per portion, food cost percent on the tax-free price, contribution margin, and a suggested price, then applies menu engineering (Star, Plowhorse, Puzzle, Dog) with a tested Python calculator.
Compares commute options - car (fuel or EV), transit, bike, e-bike, walking, day-share mixes and park-and-ride legs - per month and year with cash cost, door-to-door time, time cost at your own hourly value, cost per trip and CO2. Picks pass vs pay-per-ride for the days you ride, separates car running costs from fixed costs, and shows the break-even value of an hour. Includes a stdlib Python calculator with --self-test.
Estimates what each home appliance costs to run from its watts, hours per day and your electricity tariff. Reads a CSV, works out kWh and cost per day, month and year, standby (vampire) loads, each appliance's share and off-peak pricing, compares the total with a real bill, and ranks savings ideas such as LED bulbs, 30 C washes and cutting standby by yearly savings. Includes a stdlib Python estimator with --self-test.
Splits shared costs for a group trip, house share, or event: equal, subset, weighted, or exact splits, mixed currencies with stated rates, and repayments already made, all in integer cents so totals match. Produces per-person balances and a short "who pays whom" list (at most one transfer fewer than people). Use when friends ask "who owes what?" after a trip or a shared house month. Includes a stdlib Python splitter with --self-test.
