All tools

Word Counter

Free online word counter: instantly count words, characters (with and without spaces), sentences, paragraphs and reading time. Private, no sign-up.

Case Converter

Convert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, snake_case or kebab-case instantly. Free online case converter, no sign-up.

Online Notepad

Free online notepad that saves automatically in your browser. No sign-up, no server storage: write notes, count words and download them as a text file.

Slug Generator

Turn any title into a clean, SEO-friendly URL slug. Removes accents and special characters, lowercase, hyphens or underscores. Free online slug generator.

Online Text Editor

Free online text editor for plain text: write, open .txt and .md files from your device, download them, or sign in to save them in your account and open them anywhere.

Remove Duplicate Lines

Remove duplicate lines from any list or text instantly. Options for case sensitivity, trimming spaces and removing empty lines. Free, private, no upload.

Sort Lines

Sort lines of text alphabetically (A–Z or Z–A), numerically, by length or reverse their order. Free online line sorter that runs in your browser.

Lorem Ipsum Generator

Generate lorem ipsum placeholder text by paragraphs, sentences or words. Copy or download dummy text for mockups, templates and layouts. Free.

Reverse Text

Reverse text online: write backwards letter by letter, reverse the word order or flip the order of lines. Works with emoji and accents. Free.

Web Search

One search box for Google, Bing and DuckDuckGo: pick your search engine from the dropdown and search. Your query goes straight to the engine, never to us.

Weather

Free weather forecast for any town or your current location: temperature, rain, wind and humidity now, hour by hour for 24 hours and for the next 9 days.

Dutch Energy Prices

Today’s and tomorrow’s Dutch electricity price per hour and the gas price per day, with and without VAT. See the cheapest hours for your dishwasher, laundry or EV.

Website Shortcuts

Make a start page of shortcuts to your favourite websites, each with its own icon. Add, edit, reorder and remove links. Saved in your browser; sign in to keep them on every device.

VeilChat

Message someone you know with a virtual number and a PIN instead of your phone number. No app, no email address. Messages are stored encrypted and deleted after 30 days.

Cover Grid Maker

Make a grid of your favourite game covers or movie posters: search, drag to arrange, then download a PNG or share it. Save your grids to your account. Free.

Photo Editor

Edit photos online for free: layers, crop, rotate, resize, brightness, contrast, blur and filters. Runs in your browser – your pictures are never uploaded.

Base64 Encode & Decode

Encode text to Base64 or decode Base64 to text online. Full UTF-8 support and URL-safe Base64URL option. Free, instant and private. Also via API.

URL Encode & Decode

Percent-encode text for safe use in URLs and query strings, or decode encoded URLs back to readable text. UTF-8 support. Free online URL encoder.

JSON Formatter & Validator

Format, beautify, minify and validate JSON online. Choose 2 spaces, 4 spaces or tabs, and get clear error messages for invalid JSON. Free and private.

Social Media Preview

Preview how a page link may look in a social post. Check its Open Graph and Twitter Card title, description and image.

Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text instantly. UTF-8 input, uppercase option, runs in your browser. Also via API.

UUID Generator

Generate random UUID v4 or time-ordered UUID v7 identifiers online, in bulk up to 500 at once. Uppercase and no-hyphen options. Free, also via API.

SSL Certificate Checker

Free SSL certificate checker: see a domain's chain, expiry, SANs, issuer and trust, or decode a PEM certificate – PKIoverheid and UZI too.

Password Generator

Generate strong, random passwords with letters, numbers and symbols. Choose the length, exclude look-alike characters and see the entropy. Free and private.

OIN Lookup

Find the OIN (Organisatie-identificatienummer) of a Dutch government body or company by name, OIN or KvK number. Shows sub-OINs, status and BSN authorisation.

eID 4.4 SAML Validator

Validate DV or LC SAML metadata against eID SAML 4.4: XML schema, signature, PKIoverheid certificates, OIN, entityID, endpoints and algorithms. Free, nothing stored.

eTD Service Catalogue Editor

Load an OIN's entries from the eTD service catalogue, edit service definitions, instances, attributes, classifiers and certificates, and generate checked catalogue XML. Free.

File Explorer

A simple online file explorer for your free Synsi account: browse folders, upload files, rename, move, download and delete the documents you saved from tools.

Length Converter

Free length converter for metres, centimetres, feet, inches, yards, miles, kilometres and nautical miles. Exact factors and instant results.

Weight Converter

Free weight converter for kilograms, grams, pounds, ounces, stone and tonnes. Exact factors for kg to lb, lb to kg and stone to kg conversions.

Temperature Converter

Free temperature converter for Celsius, Fahrenheit and Kelvin. See the formulas, oven temperatures and body temperature conversions instantly.

Volume Converter

Free volume converter for litres, millilitres, US and UK gallons, cups, pints, quarts, fluid ounces, tablespoons, teaspoons and cubic metres.

Area Converter

Free area converter for square metres, square feet, acres, hectares, square kilometres, square miles, square yards and square inches. Exact results.

Speed Converter

Free speed converter for kilometres per hour, miles per hour, knots, metres per second and feet per second. Exact results for driving and sailing.

Time Converter

Free time converter for milliseconds, seconds, minutes, hours, days, weeks and years. Convert hours to minutes, days to hours and more instantly.

Data Storage Converter

Free data storage converter for bits, bytes, KB, MB, GB, TB, PB and binary KiB, MiB, GiB and TiB. See why a 1 TB drive shows 931 GB.

Pressure Converter

Free pressure converter for bar, psi, pascal, kilopascal, megapascal, millibar, atmospheres and torr. Ideal for tyre, weather and hydraulic pressure.

Energy Converter

Free energy converter for joules, kilojoules, megajoules, watt-hours, kilowatt-hours, calories, kilocalories and BTU. Exact factors, instant results.

Power Converter

Free power converter for watts, kilowatts, megawatts, mechanical horsepower, metric horsepower (PS) and BTU per hour. Exact, instant results.

Frequency Converter

Free frequency converter for hertz, kilohertz, megahertz, gigahertz, terahertz and revolutions per minute (RPM). Instant and exact results.

Angle Converter

Free angle converter for degrees, radians, gradians, arcminutes and arcseconds. Convert degrees to radians and back with the exact formula.

Force Converter

Free force converter for newtons, kilonewtons, pound-force, kilogram-force and dynes. Convert N to lbf, kgf to N and more with exact definitions.

Torque Converter

Free torque converter for newton-metres, kilonewton-metres, pound-feet and pound-inches. Convert engine torque and torque wrench settings exactly.

Fuel Economy Converter

Free fuel economy converter for litres per 100 km, kilometres per litre, US MPG and UK (imperial) MPG. Compare car fuel consumption worldwide.

Density Converter

Free density converter for kilograms per cubic metre, grams per cubic centimetre, grams per millilitre, pounds per cubic foot and pounds per US gallon.

Acceleration Converter

Free acceleration converter for metres per second squared, standard gravity (g) and feet per second squared. Convert g-force to m/s² and back.

Illuminance Converter

Free illuminance converter for lux, kilolux, foot-candles and phot. Convert lux to foot-candles for lighting design, photography and plant grow lights.

Electrical Units Converter

Free electrical units converter for volts, millivolts, kilovolts, amps, milliamps, ohms, kilohms, megohms, watts and kilowatts. Includes Ohm’s law.

Storage Calculator

Calculate how much storage a collection of files uses and how much capacity remains. Supports decimal GB and binary GiB units.

Download Time Calculator

Estimate download time from file size and internet speed. Convert GB, GiB and Mbps to a clear time estimate in seconds, minutes and hours.

Age Calculator

Calculate your exact age in years, months and days, plus total weeks and days lived and the days until your next birthday. Free online age calculator.

Week Number Calculator

Find the ISO 8601 week number for any date. See the week-year, weekday, and Monday-to-Sunday dates with this free week calculator.

Date Add or Subtract Calculator

Add or subtract a number of days, weeks, months or years from a date, with month-end dates handled safely.

Time Duration Calculator

Calculate the elapsed time between two clock times, including intervals that cross midnight.

Time Zone Converter

Convert a local date and time between common IANA time zones and see the UTC offset and Unix timestamp.

Unix Timestamp Converter

Convert Unix timestamps in seconds or milliseconds to a readable UTC date and back again.

Leap Year Calculator

Check whether a year is a leap year and see how many days it contains.

Calendar

Free online calendar: today’s date, ISO week number, day of the year and quarter, month and year views with week numbers, plus public holidays for 5 countries.

Fraction Calculator

Add, subtract, multiply, divide or simplify fractions and see the exact result and decimal equivalent.

Ratio Calculator

Simplify a two-part ratio and calculate each part as a percentage of the total.

Average Calculator

Find the arithmetic mean of a list of numbers, together with their sum and count.

Probability Calculator

Calculate the probability of an event from favorable outcomes and the total number of equally likely outcomes.

Standard Deviation Calculator

Calculate the mean, variance and standard deviation of a data set using a population or sample formula.

Variance Calculator

Calculate population or sample variance and standard deviation from a list of observations.

Percentage Change Calculator

Calculate the percentage increase or decrease between an original value and a new value.

GCD and LCM Calculator

Find the greatest common divisor (GCD) and least common multiple (LCM) of two whole numbers.

Scientific Calculator

Evaluate common scientific functions including trigonometry, logarithms, powers, roots and reciprocals.

Quadratic Equation Calculator

Solve a quadratic equation in the form ax² + bx + c = 0 and inspect its discriminant and roots.

Linear Equation Calculator

Solve a linear equation in the form ax + b = 0 for x.

Exponent Calculator

Calculate a base raised to a power, including fractional and negative exponents.

Logarithm Calculator

Calculate a logarithm for any positive value and valid positive base other than one.

Square Root Calculator

Find the principal square root of a non-negative number.

Factorial Calculator

Calculate n factorial, the product of all positive integers up to n.

Z-Score Calculator

Convert a value to a z-score using its mean and standard deviation.

Confidence Interval Calculator

Estimate a confidence interval for a mean using a sample mean, standard deviation, sample size and confidence level.

Mean, Median and Mode Calculator

Calculate the mean, median, mode and count for a set of numbers.

Range Calculator

Find the minimum, maximum and range of a list of numerical values.

Linear Regression Calculator

Fit a straight line to paired x and y observations and calculate slope, intercept and R-squared.

Correlation Coefficient Calculator

Calculate Pearson’s correlation coefficient from paired x and y data.

P-Value Calculator

Estimate a one-tailed or two-tailed p-value from a z-score under the standard normal distribution.

Normal Distribution Calculator

Calculate the z-score, cumulative probability and probability density for a normal distribution.

Bayes' Theorem Calculator

Update a prior probability using a true-positive rate and false-positive rate to calculate a posterior probability.

Percentage Calculator

Free percentage calculator: find X% of Y, what percent X is of Y, the percentage change between two numbers, or add and subtract a percentage.

Inflation Calculator

Free inflation calculator: see what something will cost in the future or how much your money will be worth, at any yearly inflation rate.

Discount Calculator

Calculate the savings and sale price after a percentage discount.

Investment Return Calculator

Compare an initial investment with its ending value and calculate total and annualized return.

ROI Calculator

Calculate net profit and return on investment from project cost and revenue.

Tip Calculator

Work out a tip, the total bill and each person’s share.

Split Bill Calculator

Add tax and tip to a bill, then split the total evenly across a group.

Salary Calculator

Convert gross annual salary into an estimated gross and take-home amount per pay period.

Hourly to Annual Salary Calculator

Convert an hourly wage to an annual estimate or an annual salary to an hourly equivalent.

Overtime Calculator

Estimate regular and overtime pay for a work period using your hourly rate and overtime multiplier.

Pay Raise Calculator

Calculate your new annual salary and the value of a percentage raise.

Rent vs Buy Calculator

Compare estimated rent payments with net homeownership costs over a selected time period.

Debt Payoff Calculator

Estimate payoff time and interest from a debt balance, APR and fixed monthly payment.

Credit Card Interest Calculator

Estimate credit card interest and remaining balance over a selected number of months.

Emergency Fund Calculator

Set a savings target from monthly essential expenses and estimate how long to fill the gap.

Retirement Calculator

Project savings to a target retirement age and compare the result with an income-based target.

Baby Boy Name Generator

Generate baby boy name ideas and filter them by first letter. Explore timeless and modern names, then copy or download your shortlist for free.

Baby Girl Name Generator

Generate baby girl name ideas and filter them by first letter. Explore timeless and modern names, then copy or download your shortlist for free.

BMI Calculator

Calculate your body mass index (BMI) in metric or imperial units, see your WHO weight category and the healthy weight range for your height. Free.

Body Fat Calculator

Estimate body fat percentage from age, height, weight and sex with a BMI-based equation. Includes metric and imperial units. Free adult calculator.

TDEE Calculator

Estimate your total daily energy expenditure (TDEE) from age, height, weight and activity level. Includes metric and imperial units. Free adult calorie calculator.

BMR Calculator

Estimate your basal metabolic rate (BMR) from age, height, weight and sex. Supports metric and imperial units. Free adult BMR calculator.

Calorie Calculator

Estimate how many calories you need each day to maintain your weight. Enter your age, height, weight and activity level. Free calculator for adults.

Ideal Weight Calculator

Estimate an adult weight range for your height based on BMI values of 18.5 to 24.9. Includes metric and imperial units and a reference midpoint.

Calorie Deficit Calculator

Estimate maintenance calories and a goal-based daily target from your age, height, weight and activity. Compare BMR formulas and see optional macro estimates.

Protein Intake Calculator

Protein intake by body weight for general, active and athletic adults.

Water Intake Calculator

See a reference for total daily water intake based on life stage.

Waist-to-Height Ratio Calculator

Calculate your waist-to-height ratio as an adult screening measure.

Lean Body Mass Calculator

Estimate fat-free mass from body weight and body-fat percentage.

Calories Burned Calculator

Estimate energy use from body weight, activity and exercise duration.

Running Pace Calculator

Find your pace per kilometre and mile from distance and finish time.

One Rep Max Calculator

Estimate a one-repetition maximum from the weight and repetitions completed.

Heart Rate Zone Calculator

Estimate five training heart-rate zones from age-predicted maximum heart rate.

Sleep Calculator

Choose a wake time and see bedtimes allowing for 7, 8 or 9 hours of sleep.

Due Date Calculator

Estimate a pregnancy due date from the first day of the last menstrual period.

Ovulation Calculator

Estimate ovulation and a fertile window from period date and cycle length.

Pregnancy Weight Gain Calculator

Compare current gain with a singleton pregnancy reference range based on pre-pregnancy BMI.

Vitamin & Mineral Intake Calculator

Vitamin and mineral intake calculator: see the US RDA or AI and the EU PRI or AI with upper limits for 23 nutrients, by age, sex, pregnancy and breastfeeding.

Supplement Stack Calculator

Supplement stack calculator: add up vitamins and minerals from all your products, spot nutrients you take twice and compare totals with US and EU upper limits.

Supplement Label Analyzer

Supplement label analyzer: paste a Supplement Facts label to see each vitamin and mineral against US and EU upper limits, including overlap with other products.

Supplement Dose Calculator

Supplement dose calculator: enter a vitamin or mineral, the amount per serving and servings per day to see your intake as a share of the RDA and upper limit.

Vitamin D Calculator

Vitamin D calculator: convert IU to µg, add food and other supplements, and compare your daily vitamin D with the US RDA, EU AI and the 100 µg upper limit.

Elemental Mineral Calculator

Elemental mineral calculator: convert the weight of magnesium citrate, calcium carbonate, zinc gluconate, ferrous sulfate and more into the elemental amount.

Magnesium Calculator

Magnesium calculator: find the elemental magnesium in magnesium citrate, glycinate, oxide, malate, taurate and threonate, and compare it with the upper limit.

IU Converter

IU converter for vitamins: convert international units to micrograms or milligrams and back for vitamin D, vitamin A (retinol, beta-carotene) and vitamin E.

Paint Calculator

Estimate wall area and the paint needed for one or more coats, including an allowance for paint lost to spills and touch-ups.

Flooring Calculator

Estimate the floor area for one or more rooms, add a cutting-waste allowance and calculate how many flooring packs to buy.

Tile Calculator

Calculate the number of floor tiles and boxes needed from room size, tile dimensions, box quantity and a cutting-waste allowance.

Concrete Calculator

Estimate concrete volume and the number of ready-mix bags for a rectangular slab, footing or post base.

Gravel Calculator

Estimate the gravel volume for a rectangular area from its length, width and planned depth, with an optional extra allowance.

Mulch Calculator

Work out the volume of mulch needed to cover a garden bed at your chosen depth, including an optional extra allowance.

Soil Calculator

Estimate the amount of topsoil or garden soil needed to fill a rectangular bed or raised planter.

Wallpaper Calculator

Estimate wallpaper rolls from wall dimensions and roll size, with extra material for matching a repeating pattern.

Roofing Calculator

Estimate roof covering area from roof length, sloped length, roof sections and a waste allowance.

BTU Heating Calculator

Estimate the heating output in watts and BTU per hour from room floor area and an adjustable heat-load assumption.

Air Conditioner Size Calculator

Estimate a room air conditioner size in BTU per hour and cooling tons from room area, sun exposure and occupancy.

Electricity Cost Calculator

Estimate monthly energy use and electricity cost for an appliance from its wattage, daily use and your price per kilowatt-hour.

Solar Panel Calculator

Estimate a solar array size and panel count from monthly electricity use, peak sun hours, system efficiency and panel wattage.

Water Tank Calculator

Calculate the capacity of a rectangular or cylindrical water tank from its internal dimensions.

Room Area Calculator

Calculate the floor area and combined perimeter for one or more rectangular rooms in metric or imperial units.

Sudoku

Play Sudoku free in your browser: four difficulty levels, notes, hints, undo and a timer. Every puzzle has exactly one solution. Share a puzzle with a link. No sign-up, no ads.

Five Letters

Guess the five-letter word in six tries. A new daily puzzle for everyone, unlimited practice, streaks and statistics, a result to share without spoilers. Free, no sign-up.