Everyday calculators

Pick the question, enter X and Y, and read the answer with the formula used.

Enter the original price and the discount to see the sale price and what you save, then stack a second coupon or add tax for the checkout total.

Enter a price and pick a state to see the tax and total, or switch the mode to pull the tax out of a price that already includes it.

Enter a value and pick the units for length, weight, kitchen volumes and temperature, using exact definitions rather than rounded approximations.

Enter a date of birth to get an exact age today, or on any date you choose, down to the day.

Enter two dates to get the number of days between them, the same span in weeks, months and years, and how many of those days are weekdays.

Enter the distance, your car's mpg and the local gas price to see what the drive costs, per mile and per person.

Enter the total length of the walls and their height to see how many gallons a room takes, with doors, windows and a second coat accounted for.

Enter the slab or footing size to get the concrete in cubic yards and the number of bags, so you know whether to mix it yourself or order a truck.

Enter what the recipe makes and what you need, then an ingredient amount, to get the adjusted quantity in measurements you can actually use.