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.
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.
Builds fixed-rate loan and mortgage amortization schedules, shows how much of each payment goes to interest, and compares payoff strategies such as extra monthly payments, one-off lump sums, a higher fixed payment, or a shorter term, with interest saved, months saved, payoff date, and an APR estimate when fees apply. Use when a user asks "how much interest will I pay?", "should I overpay my mortgage?", "what if I pay 200 more a month?", or wants a payoff plan for a car, student, or home loan.
Plans a day hike leg by leg. Estimates time with Naismith's rule and Langmuir's descent corrections, adjusted for terrain, fitness, pack weight and breaks, gives clock times for each leg, checks the finish against sunset and the latest safe start, and works out water to carry between refills and snacks to pack. Flags after-dark finishes, long dry stretches and hard terrain late in the day. Includes a stdlib Python planner 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.
