A daily puzzle, and the math for your next project.

• Tile Calculator

  Enter room size and sq ft per box to get your tile box count. Buy 10% extra for a straight lay, 15% for diagonal and 15–20% for herringbone.

• Topsoil Calculator

  Enter area and depth to get cubic yards and bags of topsoil. Rule of thumb: 1 cubic yard is 36 bags of 0.75 cu ft and covers 81 sq ft at 4 in deep.

• Paver Base Calculator

  Get paver base in 0.5 cu ft bags, cubic yards and tons (1 cu yd = 54 bags, about 1.4 tons). Use 4–6 in of compacted base for patios, 6–8 in for driveways.

• Gravel Calculator

  Get gravel in tons, cubic yards and bags. 1 cubic yard ≈ 1.4 tons; 1 ton ≈ 0.71 cu yd (19 cu ft) and covers about 77 sq ft at 3 in deep.

• Concrete Footing Calculator

  Concrete for deck, fence and wall footings in cubic yards and 80 lb bags, plus a Sonotube chart. A 10 ft × 12 in × 8 in footing needs 13 bags.

• Grout Calculator

  How much grout do you need? Enter tile size (in, cm or mm), joint width and thickness for 25 lb bags, plus a coverage chart from mosaics to 24×24 tile.

Guides

• How Much Topsoil Do I Need for Grass or Beds?
• How Much Tile Do I Need?
• How Much Gravel Do I Need?

• Word CounterCount words, characters, sentences and reading time, and check your text against X, LinkedIn, Instagram, SMS and meta description limits.
• Case ConverterConvert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, kebab-case or CONSTANT_CASE. Stays in your browser.
• Days Between DatesCount the days between two dates, with weeks, months and years, business days and US federal holidays. Include or leave out the end date.
• Add Days to a DateAdd or subtract days, weeks, months, years or business days from a date and see the date you land on, with month ends and leap years handled.
• Age CalculatorYour exact age in years, months and days on any date, in total weeks, days and hours, with a countdown to your next birthday. Feb 29 births handled.
• Time CalculatorAdd hours and minutes to a date and time ("72 hours from now"), find the hours between two times, and add up a timesheet, with daylight saving handled.
• Time Zone ConverterConvert a time between time zones and plan a meeting: see several cities side by side, where working hours overlap, and daylight saving changes.
• Unit ConverterConvert length, area, volume, weight and temperature with exact factors, plus cubic yards, tons and bags for gravel, soil, sand and concrete.
• Number Base ConverterConvert whole numbers between binary, octal, decimal, hex and any base from 2 to 36, up to 5,000 digits, with grouped digits and a two’s-complement view.
• Cubic Yards to TonsConvert cubic yards to tons and back for gravel, sand, topsoil, river rock and concrete, with weight-per-yard tables for each material.
• Cubic Yards to BagsHow many bags make a cubic yard: 0.5 to 3 cu ft bags of mulch, soil, gravel or sand, and 40, 60 or 80 lb concrete mix bags, both ways.
• Password GeneratorMake a strong random password or passphrase on your device: choose length and characters, see its strength in bits and copy it. Nothing is sent.
• Password Strength CheckerCheck how strong your password is: a 0–4 score, crack times, and the patterns that weaken it, with tips to fix them. Checked on your device, never sent.
• Online TimerFree online timer with alarm: run several named timers at once, quick presets, Pomodoro mode, +1 min, full screen and notifications.
• StopwatchOnline stopwatch with laps: lap and split times to the hundredth, fastest and slowest lap, copy laps as text, keyboard shortcuts, full screen.
• Countdown to a DateCount down to any date and time in days, hours, minutes and seconds, and share a link that shows the same countdown in each viewer’s time zone.
• Percentage CalculatorWork out X% of Y, what percent X is of Y, percentage change, a % increase or decrease, and the original before a discount, with the formula shown.
• Fraction CalculatorAdd, subtract, multiply and divide fractions and mixed numbers like 2 3/8 + 1 5/16, simplify, and convert to decimals, with every step shown.
• Random Number GeneratorPick a random number between any two numbers, draw several with or without repeats, flip a coin or roll dice. Fair, unbiased and drawn on your device.
• Random Name PickerPaste a list and pick a random winner, shuffle it or split it into teams. Every entry has the same chance, and your list never leaves your device.
• Feet and Inches CalculatorAdd, subtract, multiply and divide lengths like 5' 7 3/8" with exact fractions, rounded to 1/16 inch, plus decimal feet, mm and cm and a tape view.
• Board Foot CalculatorBoard feet for a whole cut list: pieces × thickness × width × length, 4/4 to 16/4 hardwood or nominal 2×4s, with waste and the cost at your price.
• Slope CalculatorFind slope from rise and run, or rise or run from a slope: percent, degrees, ratio like 1:12, roof pitch and line length, in feet and inches or metric.
• Aspect Ratio CalculatorFind the aspect ratio of any width and height (1920×1080 is 16:9), resize to a ratio to solve the missing side, or get a screen’s size from its diagonal.
• Roman Numeral ConverterConvert numbers and years to Roman numerals and back, 1 to 3,999 (larger with a bar). Strict checking explains why IIII, VX or IC are not valid.
• Stair CalculatorFind risers, treads, exact riser height, run, stair angle and stringer length from the total rise, with an IRC model-code check. Inches or metric.
• Decimal to Fraction ConverterTurn a decimal like 0.375 or 0.1(6) into an exact fraction, or round inches to the nearest 1/16 or 1/32 on a tape measure, with the working shown.
• Average CalculatorPaste a list of numbers and get the mean, median, mode, range, sum, count and standard deviation, plus a weighted average, with the working shown.
• Unix Timestamp ConverterConvert a Unix timestamp to a date and a date to a timestamp. Seconds to nanoseconds, any time zone, plus a live counter of the current Unix time.
• Remove Duplicate LinesRemove duplicate lines from a list, keep the first or last copy, and sort A to Z, naturally or at random. Works in any language and stays in your browser.
• Week Number CalculatorFind the week number of any date in the ISO 8601 and US systems, or the dates a week number covers. Also day of the year, days left and quarter.
• Text CompareCompare two texts and see what changed, line by line with changed words highlighted. Ignore case or spacing, copy a unified diff. Stays in your browser.
• Scientific Notation ConverterConvert any number to scientific, E and engineering notation or back to standard form, round to significant figures, and count the sig figs you typed.
• Lorem Ipsum GeneratorGenerate lorem ipsum by paragraphs, sentences, words or an exact character count, as plain text, HTML or Markdown. Built from the classic Latin passage.
• Tip CalculatorWork out the tip, the total and each person’s share of a bill, before or after tax, with optional rounding. Exact to the cent, all in your browser.
• JSON Formatter & ValidatorValidate JSON with the exact line and column of any error, then pretty-print, minify or sort keys. Big numbers keep every digit. Runs in your browser.
• Base64 Encode & DecodeEncode text or a file to Base64 and decode it back, with correct UTF-8 for emoji and any language, URL-safe and MIME variants. Runs in your browser.
• Day of the Week CalculatorFind out what day of the week any date falls on, from year 1 to 9999. Shows the ISO week, the nth weekday of the month, and a Doomsday-rule mental method.
• GPA CalculatorWork out your GPA from credits and letter grades or percentages: unweighted, weighted (Honors, AP/IB), cumulative, and the GPA you need next.
• URL Encode & DecodePercent-encode or decode URLs and query strings with correct UTF-8, split a URL into parts and parameters, and catch double-encoding. Runs in your browser.
• Hash GeneratorHash text or a file with SHA-256, SHA-1, SHA-384, SHA-512, MD5 and CRC32, add an HMAC key, and check a checksum. Runs in your browser; nothing is uploaded.
• Color Converter & Contrast CheckerConvert any CSS color between HEX, RGB, HSL, HWB, CMYK and OKLCH, find the nearest named color, and check WCAG 2 contrast for AA and AAA text.
• Military Time ConverterConvert military time (24-hour) to standard 12-hour time and back: 1430, 2:30 pm, noon, 2400. How to say it, a 24-hour chart and the Zulu zone letters.
• Pace CalculatorWork out pace, finish time or distance from the other two for running, walking or cycling, with km and mile splits and finish times for common races.
• Gas Mileage & Fuel Cost CalculatorWork out a trip’s fuel and cost, your mileage from a fill-up, or convert MPG (US and UK), L/100 km and km/L. Split the cost between people.
• Sales Tax CalculatorAdd sales tax, VAT or GST to a price, take it out of a tax-inclusive price, or find the rate from two prices. Exact to the cent, all in your browser.
• Ratio & Proportion CalculatorSolve a/b = c/d for x by cross-multiplication with the steps shown, simplify a ratio like 6:9:15, or split a total in a ratio such as 120 in 2:3:5.
• Cooking Measurement ConverterConvert cups, tablespoons, teaspoons and ml with US, metric, Australian or UK sizes, get kitchen fractions like 3 tbsp + 1 tsp, and scale a recipe.
• UUID GeneratorGenerate random v4 and time-ordered v7 UUIDs on your device, up to 1,000 at a time, and inspect any UUID for its version, variant and embedded timestamp.
• JWT DecoderDecode a JWT to its header and payload, read exp, iat and nbf as UTC times, spot expired or alg none tokens, and check HMAC signatures. Runs locally.
• Color Contrast CheckerCheck the WCAG 2.2 contrast ratio of text on a background, see AA and AAA pass or fail, preview it live, and get the nearest text color that passes.
• Cron Expression ExplainerPaste a 5-field cron expression and read it in plain English, with the next 10 run times in your time zone or UTC. Handles names, steps and @daily.
• Loan CalculatorMonthly payment, total interest and a full amortization schedule for a fixed-rate loan, with optional extra payments. Exact to the cent, in your browser.
• CSV to JSON ConverterConvert CSV to JSON or JSON to CSV in your browser. Handles quoted fields, line breaks, any delimiter, and shows the exact line and column of an error.
• Final Grade CalculatorFind the score you need on the final exam to reach the grade you want, from your current grade and the final’s weight, or from weighted categories.
• Timesheet CalculatorAdd up weekly hours from start and end times and unpaid breaks, overnight shifts included. Shows h:mm and decimal hours, with optional pay and overtime.
• Voltage Drop CalculatorEstimate voltage drop in volts and percent for copper or aluminum wire, single or three phase, and find the smallest AWG size that stays within 3% or 5%.
• Business Days CalculatorCount working days between two dates, or add and subtract business days from a date. Skips weekends and US federal holidays on their observed dates.
• Compound Interest CalculatorFuture value with compound interest: initial deposit, rate, compounding frequency, optional monthly or yearly contributions, APY and a year-by-year table.
• HTML Entity Encoder & DecoderEscape text for safe HTML or decode named, decimal and hex character references the way browsers do, with all 2,231 standard names. Runs in your browser.
• Regex TesterTest JavaScript regular expressions: highlighted matches, capture groups, replacements with $1 or $<name>. Stops runaway patterns. Runs in your browser.
• Generator Size CalculatorAdd up running watts and the largest starting surge for the appliances you want to power, and get a generator size with amps at 120 and 240 volts.
• Image ResizerResize and compress JPEG, PNG and WebP images by width, height, percent or longest side, and convert the format. Runs in your browser; nothing is uploaded.
• Number to Words ConverterConvert numbers to English words, check amounts and ordinals, or words back to digits. Exact up to 66 digits, with optional British “and”.
• QR Code GeneratorTurn a link, text, Wi-Fi login, email or phone into a QR code. Set error correction, size and colors, then download PNG or SVG. Made on your device.
• Text to Binary ConverterConvert text to binary, hex, octal or decimal bytes and back. UTF-8 by default (é is 2 bytes, an emoji 4) or UTF-16, with a per-character breakdown.
• Chmod CalculatorConvert Unix file permissions between a checkbox grid, octal (755, 4755), ls -l text (rwxr-xr-x) and chmod commands; apply changes like u+x,go-w.
• Random Team GeneratorPaste names, choose how many teams or people per team, and split them randomly and evenly. Reshuffle, copy the teams or share a link to the same split.
• IP Subnet CalculatorWork out the network, broadcast, usable hosts, masks and binary of any IPv4 CIDR block, split it into subnets, and expand or compress IPv6 addresses.
• Unit Price CalculatorCompare products by price per ounce, pound, liter or count. Mixed units are converted exactly, ranked cheapest first, and weight versus volume is flagged.
• Conduit Fill CalculatorCheck how many wires fit in EMT, rigid, PVC or flexible conduit under NEC Chapter 9: fill percent, pass or fail, and the most of one wire size that fits.
• Electricity Cost CalculatorFind what an appliance or a list of appliances costs to run: kWh and cost per day, month and year from watts (or amps and volts), hours and your rate.
• Hourly to Salary CalculatorConvert hourly pay to salary and back across daily, weekly, biweekly, semimonthly, monthly and annual, with unpaid weeks off and overtime. Pre-tax.
• Markdown Table GeneratorBuild a GitHub Markdown table from an editable grid or pasted CSV, TSV or spreadsheet cells. Set column alignment, pad columns, and parse a table back.
• Mortgage CalculatorMonthly mortgage payment with taxes, insurance, HOA and PMI (and the month PMI ends), plus total interest and an amortization schedule. In your browser.
• URL Slug GeneratorTurn titles into clean URL slugs: hyphen or underscore, accents to ASCII, optional stop-word removal and a max length. Batch mode warns about duplicates.
• Credit Card Payoff CalculatorMonths to pay off a credit card at a fixed payment, or the payment to be debt-free in N months, with total interest and a schedule. Exact to the cent.
• Discount CalculatorSale price from a percent or dollar discount, stacked discounts as one effective percent, buy-one-get-one deals, tax after discount, and original price.
• SMS Character CounterCount SMS segments: GSM-7 (160 / 153) or UCS-2 (70 / 67), characters left, and which characters force UCS-2, with a one-click GSM-friendly fix.
• Speed, Distance and Time CalculatorEnter any two of speed, distance and time and get the third, in mph, km/h, knots and more. Add stops and a departure time to see when you arrive.
• TV Size and Viewing Distance CalculatorFind the TV size for your seating distance, or the best viewing distance for a TV size, using SMPTE and THX viewing angles, pixel limits and mount height.
• Break-Even CalculatorBreak-even units and revenue from fixed costs, price and variable cost, plus contribution margin, margin of safety and units for a target profit.
• CSS Gradient GeneratorBuild linear, radial and conic CSS gradients with up to 8 color stops, preview them live, copy the CSS or a Tailwind class, and check text contrast.
• PX to REM ConverterConvert px to rem, em, pt, % and vw/vh with an editable root font size, see a px to rem table, or paste CSS and convert every px value to rem at once.
• ROI CalculatorReturn on investment from amount invested and returned: ROI %, dollar gain and annualized ROI (CAGR) from years or dates, with optional fees and income.
• Savings Goal CalculatorHow much to save each month, biweekly or weekly to reach a savings goal by a date, or how long a fixed deposit takes. APY-based, exact to the cent.
• JSON to YAML ConverterConvert JSON to YAML or YAML to JSON in your browser. Quotes strings YAML would misread, writes | blocks, and shows the line and column of any error.
• Morse Code TranslatorTranslate text to Morse code and back, with audio at any WPM (Farnsworth too) and a full ITU-R M.1677-1 chart with punctuation, @ and SOS.
• Tire Size CalculatorDecode a tire size like 225/45R17 into width, sidewall, diameter and revs per mile, compare two sizes for speedometer error, and read load and speed codes.
• Typing Speed TestFree typing speed test for 30 seconds, 60 seconds or 2 minutes: live WPM, net WPM, accuracy and characters per minute, with the scoring formulas shown.
• Color Palette GeneratorMake a color palette from one base color: complementary, analogous, triadic, square and monochromatic harmonies, plus a 50-900 scale made in OKLCH.
• Heat Index and Wind Chill CalculatorHeat index from temperature and humidity, wind chill from temperature and wind speed, and dew point, using the NWS formulas in °F or °C, mph or km/h.
• Pomodoro TimerFree Pomodoro timer: 25-minute focus sessions, 5-minute breaks and a long break every 4 sessions. Editable lengths, auto-start, session counter, alarm.
• Standard Deviation CalculatorPaste numbers and get the standard deviation (sample and population), variance, mean, quartiles and z-scores, with the step-by-step working and a dot plot.
• Wire Size CalculatorFind the smallest copper or aluminum wire size for a load: checks NEC ampacity, the 240.4(D) small-wire limits and voltage drop, and shows which governs.
• Barcode GeneratorMake Code 128, EAN-13, UPC-A, EAN-8 and Code 39 barcodes with check digits and quiet zones. Download PNG or SVG at your size and DPI. Made on your device.
• GCF and LCM CalculatorFind the GCF (GCD) and LCM of 2 to 20 numbers with Euclid’s algorithm, prime factors and multiples shown, plus Bézout coefficients and fraction reduction.
• Image Color PickerPick any pixel of an image for its HEX, RGB, HSL and OKLCH value, and get its dominant colors with contrast. Runs in your browser; nothing is uploaded.
• Prime Factorization CalculatorCheck if a number is prime and get its prime factors, factor tree, divisors, divisor count and sum, Euler’s totient, and the next and previous prime.
• Quadratic Equation SolverSolve ax² + bx + c = 0 step by step: discriminant, exact and decimal roots (real or complex), vertex, factored form, completing the square and a graph.

All tools