The Toolkit

The exact age at testing — in years, months, and days — the way schools, speech-language pathologists, psychologists, and clinics calculate it.

Enter two birth dates to find the exact age gap between two people — in years, months, and days.

How many days are between two dates? Get the exact count in days, weeks, months, and business days — instantly.

Enter the date something happened — a quit date, a wedding, day one of a habit — and see exactly how long ago it was in days, weeks, and calendar time, plus when the next round-number milestone lands.

How many days until the big day? Pick any date — or tap a holiday — and watch the live countdown.

What date is 90 days from now — or 6 months before a deadline? Add or subtract any mix of days, weeks, months, and years from a date.

How many working days are there between two dates? Weekends are always excluded — and you can exclude US federal holidays too.

What day of the week was — or will be — any date? Pick a date and get its weekday, day of the year, ISO week number, and the days remaining in that year.

How much time is there between two times? Or what time will it be in 7 hours 45 minutes? Both tools are below.

Convert a date and time from one time zone to another — and see that same moment in every listed zone, with each zone's UTC offset on that date.

Wake up at the end of a sleep cycle, not in the middle of one. Pick a wake-up time or a bedtime — the calculator does the 90-minute math.

A countdown timer and a stopwatch in one page — set hours, minutes, and seconds, start it, and get a visual finish plus an optional beep. The stopwatch records laps. No install, no sign-up.

What is my zodiac sign? Enter a birth date to get the Western (tropical) zodiac sign, its date range, symbol, and element. For entertainment and general information.

Find your Chinese zodiac animal and element from your birth year. Enter a full birth date if you have one — it matters for January and February births, as explained below. For entertainment and general information.

Calculate board feet for any board or a whole lumber order — and what it costs at your local price per board foot.

Enter the total rise of your staircase and get risers, treads, total run, stringer length — plus a comfort check before you cut anything.

How much concrete does your slab need? Get cubic yards for ready-mix, or the exact bag count if you're mixing it yourself.

Too small a job for a ready-mix truck? Enter your slab size and get the bag count for 40, 60, and 80 lb pre-mix — buy one size, in one trip.

Add up the square footage of one room or a whole house — with a waste allowance and cost estimate for flooring, tile, sod, and more.

Find out how many gallons of paint a room actually needs — walls measured, doors and windows deducted, coats counted.

How much mulch do you need? Get cubic yards for a bulk delivery — or the exact number of bags — from your bed size and depth.

Tiles and boxes for a floor, shower, or backsplash — with the grout gap and a cut-waste allowance built in.

How much grout does your tile job need? Enter the tile size, the area, and the joint width and depth for an estimate in pounds and bags. This is a planning estimate — always check the coverage chart on your grout bag before you buy.

Cubic yards and tons of gravel, crushed stone, or rock for a driveway, path, or drainage bed — from length, width, and depth.

Materials for a wood fence — posts, sections, rails, pickets, and concrete — from the total fence length and your post spacing.

How many deck boards do you need? Board count and linear feet from your deck size, board width, and gap — plus a fastener estimate.

Enter a roof's rise and run to get its pitch in the standard x/12 format, the angle in degrees, and the rafter length for every foot of run.

How many squares of shingles does your roof need? Get squares, bundles, and underlayment rolls — from a measured roof area, or from house size plus pitch.

How many rolls do you need? Measure the room once, deduct the doors and windows, and get a roll count matched to the roll you're buying.

Carpet is cut from a roll and sold by the square yard — this calculator turns your room size into the linear feet to order and the square yards you'll actually pay for.

How many cubic yards do you need? Mix units freely — feet for the pad, inches for the depth, meters if that's what your tape says — and get yards, feet, and meters at once.

How many sheets of drywall does your room need? Get sheet counts for the walls (and ceiling, if you want it), plus screw and mud estimates.

How much insulation do you need? Get batts, rolls, or blown-in bags for your area and target R-value — and the depth to install.

How much soil, compost, or fill do you need? Get cubic yards for a bulk delivery — or exact bag counts — from your bed size and depth.

How many gallons does your pool hold? Pick the shape, enter the size and average depth, and get gallons and liters.

What size air conditioner does your room need? Get a recommended BTU range from the room's size, sun exposure, and insulation.

Measure your stack and see how much wood you really have — in cords, face cords, and ricks — or flip it around and find out how many stacks make the number of cords you want.

How much water will your tank actually hold — and how much will it weigh? Enter the dimensions for gallons, liters, substrate, and water weight.

Work out your gross pay for any pay period, with overtime at time-and-a-half (1.5×) or double time (2×).

Convert an hourly wage into a yearly salary — or a salary back into an hourly rate — based on the hours and weeks you actually work.

Add up a week of shifts: daily clock in and out times, unpaid break minutes, your hourly rate — out comes daily hours, the weekly total, the overtime split over 40 hours, and gross pay.

Turn miles driven into a reimbursement estimate: miles × your per-mile rate. Use the quick calculator for one trip, or the trip log to total a whole week or month of driving.

What does it cost to run an appliance? Enter its watts, how long it runs each day, and your electricity rate — get the daily, monthly, and yearly cost, per appliance and for the whole list.

Enter the list price and the percent off. Add a second stacked discount (like a coupon on top of a sale) and your local sales tax rate to see the true final price — and exactly what you save. This is plain shopping math; no prices or retailer offers are listed or implied here.

Add, subtract, multiply, or divide two fractions. Every answer comes back simplified, in mixed-number form when it can be, and as a decimal.

Simplify a ratio to its smallest whole numbers, scale a ratio up or down to hit a target part, solve a proportion a : b = c : x, or find a screen's aspect ratio from its width and height.

Paste any list of numbers — separated by commas, spaces, or line breaks — and get the mean, median, mode, range, and standard deviation in one pass.

Raise a base to any power — whole, negative, or fractional — or flip it around and take an nth root. Huge and tiny answers are also shown in scientific notation.

Pick what you know — two legs of a right triangle, a leg and the hypotenuse, three sides, two sides with the angle between them, or one leg and one acute angle — and get every missing side, angle, the area, and the perimeter.

Enter any single measurement — radius, diameter, circumference, or area — and get all four. Everything is computed with the full precision of π your device carries, then rounded only for display.

The pure geometry of a cylinder — a tank, pipe, can, or post hole. Enter the radius (or diameter) and the height or length, and get the volume in cubic units, liters, and US gallons, plus the surface area.

Convert Arabic numbers to Roman numerals and Roman numerals back to numbers, across the full standard range of 1 to 3999 — with strict checking, so non-standard forms are rejected with an explanation instead of silently misread.

Convert non-negative integers between decimal, binary, hexadecimal, and octal — all four bases at once, with the bit length of the value shown.

Convert between cups, tablespoons, teaspoons, fluid ounces, and milliliters — and see the weight in grams for common ingredients, because a cup of flour and a cup of honey are very different amounts of food.

Convert oven temperatures between Fahrenheit, Celsius, and Gas Mark — for recipes written in any of the three systems.

Convert between US, UK, and EU ring sizes — or work backwards from a measured inside diameter — with diameter and circumference for every size.

Convert between US, UK, and EU shoe sizes for men, women, and kids from the standard conversion tables — or measure your foot and get the nearest size in all three systems.

Turn a metric tire code like 225/65R17 into real dimensions — overall diameter, sidewall height, circumference, revolutions per mile — and compare two sizes side by side.

Convert fuel economy between US MPG, liters per 100 km, and km per liter — then price a trip from its distance, your economy, and the fuel price.

Convert between Fahrenheit, Celsius, and Kelvin in any direction — enter a temperature in one scale and see it in all three.

Convert between pounds, kilograms, ounces, grams, and stones — enter a weight in one unit and see it in all five, including the stones-and-pounds form common in the UK.

Type a color in any format and the others update instantly, with a live preview swatch. If the color exactly matches a named CSS color, the name shows too.

Speed, distance, time — enter any two and solve the third. Results come out in mph, km/h, and m/s, with a runner's pace per mile and per kilometer as a bonus.

Enter any run — distance and time — to get your pace per mile and per kilometer, and predicted finish times for the classic race distances at that same pace.

What the air temperature feels like on exposed skin once the wind is counted — using the official National Weather Service (NWS) wind chill formula.

How hot it feels when humidity slows your body's cooling — the National Weather Service heat index, from air temperature and relative humidity.

The temperature at which dew forms — the single best number for how muggy air actually feels — from air temperature and relative humidity.

Paste or type your text below — word, character, sentence, and paragraph counts update as you type, along with reading time, speaking time, and keyword density.

Paste your text, pick a case style, and copy the result. The preview updates live as you type.

Generate strong, random passwords right here on the page. The randomness comes from your browser's built-in cryptographic generator, crypto.getRandomValues — the passwords are created on your device and never sent anywhere.

Random integers in any range (with or without duplicates), random decimals, and a dice roller. The randomness comes from your browser's cryptographic generator, crypto.getRandomValues — the numbers are created on your device and never sent anywhere.

How old is your dog in human years? This uses the modern research-based formula — not the old "multiply by 7" rule — with an adjustment for your dog's size.

Dial in your brew: pick a coffee-to-water ratio and start from either the coffee or the water — the other side is worked out for you, with spoon and cup equivalents.