Utility Tools

Estimate one-rep max (1RM) using Epley, Brzycki, and Lombardi formulas.

Convert HbA1c to estimated average glucose (eAG) in mg/dL and mmol/L and back, with ADA category ranges. Educational only.

Estimate AC tonnage from room area, sun exposure, and occupancy (planning estimate).

Draw, type or upload a signature and place it on a PDF page. Processed in your browser so the document is never uploaded.

Calculate the exact age difference between two people from their birth dates, in years, months and days. Perfect for couples, siblings and friends. Free, private.

Discover how old you would be on Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune based on each planet's orbital period. A fun space calculator. Free, private.

Convert between degrees, radians, gradians, turns and mils, with the radian conversions that trip up trigonometry.

Calculate upcoming anniversary milestones (days/weeks/months/years) from a start date.

Calculate monthly electricity usage and cost for multiple appliances from wattage and hours/day.

Blend two parents' names into new name suggestions, with readability and pronunciation checks. Generated in your browser.

Generate example vaccination dates from baby DOB using common milestone intervals. Verify with local guidelines.

Convert a bread recipe to baker's percentages, scale it to any flour weight or dough quantity, and adjust hydration, salt and starter while keeping the ratios correct.

Generate barcodes in the common symbologies, with the check digits, quiet zones and sizing rules that make them actually scan.

Decode binary back to text, and diagnose the usual reasons it comes out as garbage.

Basic eligibility checker using age, weight, and days since last donation. Always confirm with your blood bank.

Estimate body fat percentage using the U.S. Navy tape method with cm measurements.

Calculate your bra size from underbust and bust measurements with US, UK and EU conversions plus sister sizes.

Strip the invisible characters and formatting damage that copied text carries, in one pass.

Count the number of business (working) days between two dates, excluding weekends, with total days and weeks. Great for projects and deadlines. Free, private.

Create downloadable .ics calendar invites with reminders that open in Apple Calendar, Outlook and Google Calendar, plus instant Google Calendar links.

Predict a child's adult height from the parents' heights using the mid-parental height method, in cm or feet and inches.

Calculate distance between two cities (major Indian cities supported) or enter coordinates manually.

Measure your clicks per second in 5 to 60 second challenges with ratings and a saved personal best. Works with touch too.

Calculate coffee and water by weight for pour over, French press, AeroPress, espresso, cold brew and batch brewing, with bloom volume, pour schedule and yield after absorption.

Estimate the conception date and window from a due date, last period or birth date, adjusted for cycle length. Educational only.

Estimate concrete volume and approximate material quantities (cement bags, sand, aggregate) by mix ratio.

Compare baseline vs current config.

Convert cooking measurements between cups, grams, millilitres, ounces and spoons, with the volume-to-weight problem explained.

Create a live countdown to any date and time — birthdays, holidays, launches, exams or new year — showing days, hours, minutes and seconds remaining. Free, private.

A new tool extracted from the codebase.

Validate a card number with the Luhn algorithm and identify the issuing network from its prefix. Runs locally, nothing is transmitted.

Build cron expressions from a schedule, and read the fields that cause the classic mistakes.

Pick the columns you want out of a CSV, reorder them, drop duplicate rows and filter by a value, then export the result as CSV, TSV or JSON without opening a spreadsheet.

Join two CSV datasets on a shared key with inner, left, right or full join semantics, see which rows matched, and export the combined result without a database or a spreadsheet.

Turn CSV or tab separated data into a Markdown table with correct escaping, optional column alignment and padded columns so the raw source stays readable.

Convert a spreadsheet of contacts into a vCard 3.0 or 4.0 .vcf file that imports into iPhone, Android, Outlook and Google Contacts, with correct line folding and escaping.

Validate a CSV file's structure and find the quoting, encoding and delimiter faults that break imports.

A new tool extracted from the codebase.

Convert digital storage units — bits, bytes, KB, MB, GB, TB and binary KiB/MiB/GiB — instantly and accurately. Free, private, browser-based.

Convert data transfer / internet speed units — bps, kbps, Mbps, Gbps and KB/s, MB/s, GB/s — instantly. Understand your real download speed. Free, private.

Add or subtract days, weeks, months or years from any date to find a future or past date. Perfect for deadlines, due dates and planning. Free, private, instant.

Find out what day of the week any date falls on — past or future — plus the day of year, week number and how long ago or away it is. Great for birthdays. Free, private.

Cycle fullscreen solid colors (red, green, blue, white, black and more) to find dead or stuck pixels on any monitor or phone.

Convert decimal numbers to hexadecimal, with the padding and two's complement rules that matter in code.

Calculate how many deck boards, joists and fasteners a deck needs from its dimensions, including gap spacing, waste allowance, board length optimisation and total material cost.

A new tool extracted from the codebase.

Calculate billable weight from parcel dimensions using carrier DIM divisors for UPS, FedEx, DHL, USPS and air freight, and see how much box space is costing you.

Generate Discord timestamp codes that display in each user's local time and update live (relative). Pick a date and time and copy every format. Free, private, instant.

Estimate how long a download takes at a given connection speed, allowing for real-world overhead.

Calculate how many drywall sheets a room needs, with openings deducted, plus screws, joint tape, compound and corner bead quantities and an estimated material cost.

Score email based on headers and subject.

Clean up text by removing all empty lines.

Convert between joules, calories, kilowatt-hours, BTU and electronvolts, including the calorie confusion that misleads everyone.

A new tool extracted from the codebase.

Estimate EV charging time and cost from battery size, charge %, charger power, electricity price, and efficiency.

Calculate fan electricity consumption and monthly cost from wattage, usage hours, and tariff.

Estimate your likely ovulation date and fertile days from cycle length. Calculated locally in your browser with nothing stored or transmitted.

Verify a file against a published checksum, and understand what a matching hash does and does not prove.

Estimate total flooring area across rooms and add wastage for purchase planning.

Convert fuel economy between US MPG, UK (imperial) MPG, kilometers per liter and liters per 100 km. Compare your car's efficiency in any unit. Free, private, accurate.

Size a standby or portable generator from the appliances you need to run, accounting for motor starting surge, power factor and altitude derating rather than adding up nameplate watts.

Calculate gravel, sand or crushed stone needed in cubic yards and tons from area and depth, with optional cost estimate.

Calculate your five heart-rate training zones from age, with the more accurate Karvonen method when you add resting heart rate.

Convert hexadecimal to decimal, and read the hex values that appear in colours, memory and error codes.

Estimate paint liters required from area, coats, coverage, and wastage.

A new tool extracted from the codebase.

Validate an IBAN with the official mod-97 checksum, verify the country specific length and format, and split it into bank code, branch code and account number.

Convert between Unicode domain names and Punycode, and spot homograph attacks.

Combine JPG, PNG and WebP images into a single PDF with page size and orientation control. Runs in your browser with no upload.

A new tool extracted from the codebase.

Check whether a website is reachable from outside your network, and interpret the result.

Convert an ISBN between the 10 and 13 digit forms, recalculate the correct check digit for each, and see the hyphenated display form with registration group and publisher elements.

Convert a JSON array into CSV with automatic column discovery, dot notation flattening for nested objects, configurable delimiters and Excel safe quoting.

Press every key to light it up on a virtual keyboard and spot dead or stuck keys, with key code details for developers.

Calculate the series resistor an LED needs from supply voltage, forward voltage and target current, with the nearest E24 standard value, the resulting real current and the required power rating.

A new tool extracted from the codebase.

Convert between symbolic and octal Linux permissions, and understand what each bit does.

Generate Lorem Ipsum placeholder text by paragraphs, sentences or words, with optional HTML markup. Runs entirely in your browser.

Validate any Luhn protected identifier or generate the missing check digit. Works for card numbers, IMEI, SIM ICCID, Canadian SIN, national provider identifiers and any other mod-10 number.

A new tool extracted from the codebase.

Generate medication reminder times from a start date/time, interval, and number of doses.

Extract metadata from images and documents, and see what a file discloses before you share it.

Convert between military (24-hour) time and standard 12-hour AM/PM time both ways, with a full reference chart.

Find the moon phase and illumination percentage for any date, with the phase name and emoji. Useful for photography, gardening and stargazing. Free, private.

Work out how many cubic yards or bags of mulch you need from bed size and depth, in imperial or metric units.

Count down the days, hours and minutes until your next birthday and see how old you'll turn. Fun and free, updates live in your browser. Private.

Solve any two of voltage, current, resistance and power to get the other two, with the full power triangle, unit prefixes and a check against common component ratings.

A distraction-free online notepad that autosaves to your browser as you type, with word count, download and print.

A free, accurate online stopwatch with start, stop, lap and reset. Records lap and split times with millisecond precision. Runs in your browser — no install.

A new tool extracted from the codebase.

Estimate ovulation date and fertile window from last period start and cycle length.

Work out how many cartons fit on a pallet in each orientation, how many pallets fill a container, and what percentage of the space and weight allowance you are actually using.

Sanitize password lists against policy rules.

Paste a list of passwords to find exact duplicates, case-only variants and same-word-different-year patterns that attackers try automatically.

A new tool extracted from the codebase.

Attach a cover page to the front of a PDF, either from another file or generated with a title block. Processed locally with no upload.

Work out the correct page order for printing a folded booklet, including the blanks needed to reach a multiple of four. Runs locally.

Generate a custom single-page PDF cover sheet with title, subtitle, footer and accent color locally in your browser. No uploads or API calls.

Remove unwanted pages from a PDF and download the result. Supports ranges and odd or even removal, processed in your browser with no upload.

Repeat selected pages inside a PDF any number of times, at a chosen position. Runs in your browser with no upload.

Extract even-numbered pages from a PDF into a new PDF locally in your browser. No uploads, no API calls, fully private.

Pull specific pages out of a PDF into a new file. Supports ranges, odd and even selection, and first or last pages. No upload required.

Extract the first N pages and last N pages from a PDF into one new PDF locally in your browser. No uploads, no API calls, fully private.

Add blank pages at chosen positions in a PDF, matching the surrounding page size. Useful for duplex printing and binding. No upload required.

Combine multiple PDF files into one in your browser. Reorder before merging, no upload, no file size limit imposed by a server, no watermark.

Inspect PDF metadata: author, creator software, creation and modification dates, page sizes and security settings. Read locally, nothing uploaded.

Detect whether a PDF mixes page sizes or orientations and list which pages belong to each size group. Runs locally in your browser with no uploads.

Extract odd-numbered pages from a PDF into a new PDF locally in your browser. No uploads, no API calls, fully private.

Count the pages in a PDF locally in your browser. Files are read on your device and never uploaded to any server.

Insert page numbers into a PDF with control over position, starting number, format and which pages are skipped. No upload required.

Get a simple position guide for a page number within a document, including front/back position, odd/even status and approximate booklet grouping.

Analyze a page-range expression against a PDF to see selected pages, duplicates, and unselected pages. Runs fully in your browser with no uploads.

Check a page label sequence against a PDF page count to find missing, duplicate or out-of-order labels. Runs fully in your browser with no uploads.

Inspect each page size, orientation and nearest common paper size in a PDF locally in your browser. No uploads, no API calls, fully private.

Rearrange the page order of a PDF by dragging or by entering a custom sequence. Processed in your browser with no upload.

Reverse the page order of a PDF in one step. Fixes documents scanned back to front. Processed in your browser with no upload.

Rotate PDF pages 90, 180 or 270 degrees, individually or all at once, and save the orientation permanently. No upload required.

Generate simple labeled divider pages as a PDF from a list of section titles. Runs locally in your browser with no uploads or API calls.

Split a PDF into separate files by page range or extract every page individually. Runs in your browser with no upload and no watermark.

Calculate simple side-by-side two-up page pairs for printing or layout planning. Runs locally in your browser with no uploads.

Stamp a text or image watermark across PDF pages with control over opacity, angle and position. Processed in your browser with no upload.

Estimate upcoming period dates from your cycle length and last period. Calculated in your browser so no cycle data is stored or transmitted.

Estimate personal CO₂e footprint from electricity, gas, transport, and flights using rough default factors.

Convert pet age to human equivalent using size and breed-adjusted curves rather than the debunked multiply-by-seven rule.

A new tool extracted from the codebase.

A new tool extracted from the codebase.

Calculate pool volume for rectangular, round, oval and kidney shapes with sloping floors, then work out the chlorine, shock, acid or alkalinity dose to reach your target reading.

Convert between watts, kilowatts, horsepower, BTU per hour and tons of refrigeration, including the several different horsepowers.

Estimate a due date from the last menstrual period or conception date, with an honest account of how approximate it is.

Convert between psi, bar, pascals, atmospheres, mmHg and inches of mercury, including the gauge versus absolute distinction.

Estimate daily protein intake based on weight and goal (maintenance, fat loss, muscle gain).

Generate QR codes for URLs, text, Wi-Fi and contact details. Adjustable error correction and size, produced entirely in your browser.

Estimate annual harvestable rainwater from roof area, rainfall, and runoff coefficient.

Generate random values of any type, with the distinction between random and cryptographically secure made explicit.

Generate cool, unique and available-looking usernames for gaming, social media and sign-ups, combining adjectives, nouns and numbers. Choose a style. Free, private.

A new tool extracted from the codebase.

Scale ingredient quantities from original servings to target servings (supports simple numbers and fractions).

A new tool extracted from the codebase.

A new tool extracted from the codebase.

Read a resistor value from its colour bands, or find the bands for a value you need. Covers 4, 5 and 6 band resistors with tolerance, temperature coefficient and E series preferred values.

Convert ring sizes between US, UK and EU systems or find your size from a ring's inside diameter or finger circumference in mm.

A new tool extracted from the codebase.

A new tool extracted from the codebase.

Calculate required airflow (CFM) from room volume and desired air changes per hour (ACH).

Record your screen, window or browser tab (with optional mic audio) directly in the browser and download the video — nothing is uploaded.

Detect your screen and browser viewport dimensions, and understand why they differ.

Test how your website looks on different screen resolutions.

Draw Secret Santa names privately in your browser with support for exclusion pairs and click-to-reveal assignments.

A new tool extracted from the codebase.

Generate cryptographic hashes of files in your browser to verify downloads and detect changes.

Overwrite file contents before deletion, and understand where shredding does and does not work.

Generate cryptographically secure random tokens for API keys, session identifiers and reset links.

Get a recommended session timeout and re-authentication policy based on your application type, from banking to social media, aligned with NIST 800-63B guidance.

Convert shoe sizes between US, UK, EU and centimeters for men and women using standard sizing charts. Find your size in any system. Free, private, instant.

Draw your signature with mouse, finger or stylus and download it as a transparent PNG ready for PDFs and documents.

Suggest bedtimes based on wake time and 90-minute sleep cycles.

Create sms: links with pre-filled messages and tel: click-to-call links for websites, QR codes and marketing campaigns.

A new tool extracted from the codebase.

Count spacebar presses freely or race timed 5–30 second challenges, with presses per second and a saved best score.

Convert between miles per hour, kilometres per hour, metres per second, knots and Mach, with the conversions that matter in practice.

A new tool extracted from the codebase.

A new tool extracted from the codebase.

Estimate number of steps, riser height, and run from total rise and tread depth.

Full-featured stopwatch with lap times and countdown timer with preset durations. Progress bar and audio notification on completion.

A new tool extracted from the codebase.

A new tool extracted from the codebase.

Get sunrise, sunset, day length, solar noon and civil twilight for any coordinates and date using the NOAA algorithm — no data sent anywhere.

Estimate BMR/TDEE and daily macros (protein/fat/carbs) using Mifflin-St Jeor and activity level.

Convert text between camelCase, PascalCase, snake_case, kebab-case, CONSTANT_CASE, Title Case and sentence case. Runs entirely in your browser.

A new tool extracted from the codebase.

Compare text files and highlight differences.

Redact personal and sensitive data from text before sharing it, and avoid the redactions that do not actually redact.

Repeat text multiple times instantly.

Convert text to binary, with the character encoding detail that decides whether it round-trips correctly.

Work out how many tiles a floor or wall needs from the area in square feet, tile length and width in centimetres, and a wastage allowance for cuts and breakage.

Add up a week of clock in and clock out times with breaks, and see regular hours, overtime past 40, daily overtime and gross pay at your rate.

Calculate the duration between a start time and end time in hours and minutes, with support for overnight periods. Great for timesheets and shifts. Free, private.

Convert between seconds, minutes, hours, days, weeks, months and years, with the ambiguities that make some of those unreliable.

Find overlapping meeting times for multiple participants using UTC offsets and working hours.

Convert lists of Unix timestamps to readable dates in bulk, with timezone handling and the seconds-versus-milliseconds problem.

Convert Unix timestamps to human-readable dates and back, in seconds or milliseconds, across time zones and ISO 8601. Runs in your browser.

Convert multiple timestamps to a single timeline.

Estimate total toll cost for a trip using count+average or a list of toll values.

A new tool extracted from the codebase.

Convert between units across twelve measurement families at once, seeing the value in every related unit rather than one at a time, with exact and defined factors shown.

Calculate or verify the check digit for UPC-A, UPC-E, EAN-13, EAN-8, ITF-14 and GTIN-14 barcode numbers, and convert between the GTIN formats.

Estimate how long a UPS will run your load, size the VA rating you need, and apply Peukert derating so the figure reflects real battery behaviour rather than the marketing number.

Encode or decode many URLs at once, with the component rules that decide which characters change.

Parse a User-Agent string into browser, engine, operating system and device. Explains why UA strings are unreliable and what to use instead.

Generate a QR code that adds your contact details (name, phone, email, company, website) to any phone with one scan.

Validate a 17 character VIN with its official check digit, and decode the manufacturer region, model year and assembly plant from the number itself with no lookup required.

Calculate a resistive divider output voltage, pick the resistor pair for a target voltage, and see the loading error a real input impedance introduces before it surprises you.

Calculate voltage drop over a cable run and find the wire gauge that keeps it within limits. Supports AWG and metric cross sections, copper and aluminium, single phase and three phase.

Estimate wallpaper rolls needed from total wall width/height and roll size.

Estimate daily water needs from body weight, activity and climate, and understand why the eight-glasses rule has no evidence behind it.

Estimate water tank size in liters from household size, liters per person per day, and storage days.

Test your webcam and microphone before a video call — live preview, resolution info and a mic level meter, all on-device.

Find the ISO 8601 week number for any date, plus the day of year and the date range of that week. Useful for planning and scheduling. Free, private, instant.

Generate a WhatsApp message link (wa.me) with a prefilled message and phone number.

Create a QR code that joins a WiFi network on scan, with the format, security types and privacy considerations explained.

Count words, characters with and without spaces, sentences and paragraphs, with estimated reading time. Runs entirely in your browser.

A new tool extracted from the codebase.

Build YouTube chapter timestamps for your video description in the correct format (00:00 Intro). Add chapters, auto-sort, and copy a ready-to-paste list. Free, private.

View and save the thumbnail of any YouTube video in all available sizes up to HD 1280x720, straight from YouTube's public CDN.