More

Enter a date of birth for an exact age in years, months and days as of today — or a chronological age as of any reference or test date. Age on any date, birth year and age difference run on the same page.

Convert brown sugar between cups, grams and ounces, work out the white sugar and molasses that make a given amount, and compare substitutes — with the packing convention behind every number shown.

Enter any date to find its weekday. The result also shows where the date falls in the year, its ISO week, and the calendar convention used — plus the month around it, the same date in nearby years, and, for dates before the Gregorian reform, what the calendar actually said in a particular country.

Work out the hours between two times, with the break taken off — then turn the same entry into a weekly timecard, duration arithmetic, hours from now, or decimal hours, without leaving the page.

Shoe size conversions are recommendations, not exact unit conversions: a size number is a marking convention, so US, UK, EU and Asian sizes only relate to each other through the foot the shoe is built for. This converter goes size to foot length to size, and shows the range and the source behind every answer.

Compare two or more product offers on a common per-unit basis, verify a retailer's shelf-tag unit price against the arithmetic, or measure shrinkflation between an old and new pack size.

Calculate an acceptance rate from applicants and admits, analyze a complete admission funnel, or compare your academic profile with officially published college ranges—without false precision.

Find your current attendance rate and absence rate, the classes you still need to attend to reach a target, how many you can miss, whether the target is even reachable, and a weighted view across several subjects. For the marks behind the attendance there are separate tools: your GPA, a course grade, a test score percentage, or the graduation rate for a whole cohort.

Calculate your term or cumulative GPA, plan the GPA you need to reach a target, and model how retaking a course could change the result. Every calculation shows the formula, the numbers substituted into it, course-level impact, and the assumptions used.

Model a whole course with the Course planner or grade a single score, a weighted course, a points-based course, or find the score you need on the final — one tool, five modes (Course planner, Single score, Weighted course, Points-based course, Final grade target), with letter grades on a scale you can customize.

Work out a graduation rate from graduates and a starting cohort — the headline measure of whether an institution actually delivers on its promise.

Work out a test score as a percentage from the marks you earned and the total available — the standard way scores convert into a grade, with the percentage you missed shown alongside.

Calculate how many BTUs you need for an air conditioner, a heater or a room. Adjust for size, ceiling height, climate, insulation, sunlight and occupancy — and see exactly which of them is driving the number. Start from the room's floor area if you do not have it to hand, and use unit conversion to move between BTU, kilowatts and tons.

Work out exactly how much concrete your job needs — in cubic yards, cubic feet, cubic metres, litres or bags — for slabs, footings, walls, post holes, columns, circular pads, tubes, curbs, stairs and tapered pours. Every field takes its own unit, several sections add into one order, and the exact geometric volume is always shown beside the amount to order.

Work out exactly how much gravel a job needs — for one area or a whole layered driveway — in US short tons, metric tonnes, cubic yards, cubic metres or bags, with the density you are actually using named and sourced, loose and compacted kept apart, and the cost of your own suppliers compared side by side.

Work out exactly how much mulch a job needs — for one bed or for a whole yard of beds, borders and tree rings — in cubic yards, cubic feet, litres or bags, with the mulch already on the ground taken off the top and the bagged and bulk purchase costed side by side.

Work out how many tiles and how many boxes a job actually needs — for a floor, a wall, a shower, a backsplash or a whole multi-surface project — with the cut loss, the reserve and the box overage reported as three separate numbers instead of one vague word.