Everyday
Short tools for short questions. Nothing here needs an explanation longer than the calculation, so the pages stay out of the way. The answer is above the fold and the reasoning is below it for the times you want to check.
Dining
Tip CalculatorTip and split, with optional rounding-up so nobody is left counting out small change.Split Bill CalculatorSplit a bill evenly, with optional tip and tax. For an uneven split by what each person ordered, use the roommate expense splitter.Restaurant Bill with Tax and TipA restaurant bill with tax, service charge and tip, split between people. Tipping on the pre-tax amount rather than the total is the convention, and the difference is not trivial on a large bill.Pizza Size Value CalculatorWhich pizza is better value per square inch. Area grows with the square of the diameter, so a 16 inch pizza is not a third bigger than a 12 inch one, it is nearly twice the size.
Shopping
Sale Price CalculatorSale price after one or two discounts and tax. Two stacked discounts do not add: thirty percent then twenty percent is forty-four percent off, not fifty.Coupon Stacking CalculatorWhich order to apply a percentage and a flat coupon. Percentage first is always at least as good, because applying the flat amount first shrinks the base the percentage works on.Price per Unit Comparison CalculatorUnit price comparison between two pack sizes. The larger pack is not reliably cheaper per unit, and supermarkets price the exceptions deliberately.
Budgeting
50/30/20 Monthly Budget CalculatorA monthly budget against the common frameworks, computed on take-home pay. The 50/30/20 rule is stated on take-home and quoted on gross often enough to matter, and the two differ by roughly the tax you pay.Roommate Expense SplitterWho owes whom after shared expenses, minimising the number of transfers. Balances always sum to zero, which is the check that the arithmetic is right.Streaming Service Comparison CalculatorStreaming subscriptions costed per hour actually watched. The per-hour figure is what exposes the service you have paid for every month and opened twice.Coffee Cost CalculatorCafe coffee against making it at home, with the difference compounded. The point is not that buying coffee is wrong, but that the compounded figure is rarely what people expect.
Vehicle
Fuel Cost CalculatorFuel cost for a journey in any of the four efficiency units in common use, with the cost per kilometre and the split between passengers. Fuel is the visible cost of driving and usually not the largest one.Fuel Efficiency CalculatorFuel efficiency from distance and fuel used, across two legs if you have them, in all four units. Combining legs by averaging their kmpl figures is wrong, and the page shows both answers so the size of the error is visible.EV vs Petrol Cost ComparisonHow long an electric car takes to pay back its price premium in running cost, and whether it does so inside the period you plan to keep it. Distance driven decides this more than any price does: the same two cars break even in half the time at twice the mileage.EV Charging Cost and Time CalculatorEV charging time and cost. Charging rate tapers sharply above about eighty percent, so the last twenty percent can take as long as the first sixty on a fast charger.Total Cost of Car Ownership CalculatorThe full cost of running a car per kilometre and per month, with depreciation included. Depreciation is usually the largest single cost and the only one nobody pays monthly, which is why it goes unnoticed until the car is sold.
Travel
Road Trip Cost CalculatorThe full cost of a road trip, including tolls and the wear the distance puts on the car, compared against the fare for going by train or air. Comparing a fare to fuel alone is the mistake: it leaves out tolls and the several rupees a kilometre the car itself costs.Flight Cost per Mile CalculatorFlight cost per kilometre and per hour, with extras included. Cost per kilometre falls sharply with distance, which is why a short hop can look expensive next to a long haul that costs three times as much.Currency Exchange with Fees CalculatorThe true cost of a currency exchange, separating the rate markup from the visible fees. The spread is almost always the largest component and is the one not shown to you.Airline Miles Value CalculatorWhat a mile is actually worth on a specific redemption. The taxes and surcharges still payable on an award must come off the cash price first, and on some airlines they consume most of the value.
Home
Moving Cost CalculatorMoving cost by home size and distance, including the return leg that most quotes bury and the floor charges that surprise people on moving day. Transit insurance at one and a half percent of declared value is the cheapest part of the bill and the most often declined.Rent Affordability CalculatorAffordable rent, with the income basis stated. The thirty percent rule was written against take-home pay and is routinely applied to gross, which sets the budget too high by whatever you pay in tax.Security Deposit Interest CalculatorInterest due on a rental security deposit. Several Indian states mandate interest on deposits held, and where nothing is mandated the deposit loses real value every year it sits.Rent Increase CalculatorA rent increase in money rather than percent, and where repeated increases lead. Ten percent a year doubles the rent in seven and a half years, which a single year of the increase does not make obvious.Rent Split by Room Size CalculatorRent split by room size, income or equally, with common areas divided equally first. Splitting the whole rent by bedroom size overcharges the large room, because the kitchen and living room are shared regardless.
Pets
Pet Food and Cost CalculatorLifetime cost of a pet, including an emergency provision. Routine costs are easy to estimate and unplanned veterinary bills are what actually strain people, so they are provisioned for rather than ignored.Dog and Cat Age CalculatorA dog age conversion that reflects how dogs actually age. The first year is worth about fifteen human years and the second about nine, after which larger breeds age faster than small ones.Aquarium Volume CalculatorActual aquarium water volume, which is typically a fifth below the nominal figure. Glass thickness, substrate and the gap below the rim all displace water, and dosing by nominal volume overdoses the tank.
Events
More
Credit Card Rewards Value CalculatorCredit card rewards net of the annual fee, with the monthly cap applied. Headline accelerated rates are almost always capped, and the cap is what determines the real return.Cashback Comparison CalculatorTwo cashback cards compared with caps applied. A capped five percent card loses to an uncapped one and a half percent card above a certain spend, and that crossover point is the whole comparison.Lawn and Garden Fertilizer CalculatorFertiliser quantity from a nutrient application rate. Rates are given as the nutrient, not the product, so the concentration on the bag is what converts one into the other.Plant Spacing CalculatorHow many plants fit a bed at a given spacing. Staggering the rows fits about fifteen percent more in the same area for the same spacing between neighbours.