Tools
Tools for running and growing a business online.
Calculators, converters and generators that do the job properly. No sign-up and no email address, and every one of them works on the first click.
A/B test significance calculatorProFind out whether your test result is real or noise, using the same two-proportion test statisticians use.BusinessAd budget plannerWork backwards from a revenue target to the ad budget, clicks and conversions you need.MarketingAd spend and ROAS calculatorWork out return on ad spend, cost per click and cost per acquisition, and the break-even you need.MarketingAdSense readiness checkerProEnter your address and we fetch the site, run the checks Google's reviewers apply, and hand back a prioritised fix list.MarketingAge calculatorWork out an exact age in years, months and days, and when the next birthday falls.DataAspect ratio calculatorResize while keeping proportions, and find the ratio of any width and height.DesignBase64 encoder and decoderEncode text to Base64 or decode it back, with URL-safe output for tokens and query strings.DeveloperBill splitterSplit a bill between people, with a tip and optional uneven shares.BusinessBreak-even calculatorFind how many units you must sell to cover your fixed costs, and what that is worth in revenue.BusinessBulk URL slug generatorTurn a list of titles into URL slugs in one go, and flag any that collide.MarketingBusiness schema generatorGenerate the hidden code that tells Google your opening hours, phone number and location.MarketingCampaign link builderBuild tagged links so you can finally tell which post, ad or email actually brought the customer in.MarketingCanonical and meta robots generatorGenerate canonical tags and robots directives correctly — the tags most often set the wrong way round.MarketingCard, IBAN and ISBN validatorCheck a card number, bank IBAN or ISBN is internally valid before it causes a failed payment or a bad record.BusinessCase converterConvert text between sentence case, title case, camelCase, snake_case, kebab-case and more.TextCash runway and burn rateProHow many months of cash you have left at the current burn, and what it takes to reach break-even.BusinessCharacter frequency counterCount how often each character appears — for ciphers, data cleaning and spotting stray symbols.TextChurn and retention calculatorTurn a monthly churn rate into what it actually means: annual loss, average lifetime and revenue at risk.BusinessColour blindness simulatorSee how a palette looks to the 1 in 12 men with colour vision deficiency — and whether it still works.DesignColour contrast checkerCheck text and background against WCAG AA and AAA — the accessibility test most sites quietly fail.DesignColour converterConvert a colour between HEX, RGB and HSL, and get the CSS for each.DesignColour palette generatorBuild a harmonious palette from one colour: complementary, triadic, analogous and a full tint scale.DesignCompound interest calculatorProject savings or investment growth, including regular contributions, and see what is growth and what is yours.BusinessConversion rate and funnel calculatorWork out conversion at each step of a funnel and find where you lose the most people.MarketingCron expression explainerRead a cron schedule back in plain English, so you know when it will actually run.DeveloperCSS box shadow generatorDesign a box shadow visually and copy the CSS, including multi-layer shadows that look natural.DesignCSS gradient generatorBuild a linear or radial CSS gradient and copy the code, with a live preview.DesignCSS minifierStrip comments and whitespace out of CSS and see how much smaller it gets.DeveloperCSV column extractorPull out, reorder or drop columns from a CSV without opening a spreadsheet.DeveloperCSV to JSON converterTurn a spreadsheet export into JSON, handling quoted fields and embedded commas properly.DeveloperCustomer acquisition cost and lifetime valueProWork out what a customer costs to win, what they are worth, and whether that ratio is sustainable.BusinessDate difference calculatorCount the days, weeks, months and working days between two dates.DataDays sales outstanding calculatorMeasure how long customers actually take to pay, and what tightening that up frees in cash.BusinessDepreciation calculatorWrite an asset down over its life, straight line or reducing balance, year by year.BusinessDiscount and sale price calculatorWork out a sale price, the saving, and what a discount does to your margin before you commit to it.BusinessDownload and transfer time calculatorHow long a file takes to transfer at a given connection speed — and where the megabit/megabyte confusion bites.DataDuplicate and overlap finderCompare two lists and see what is in both, what is only in one, and what is duplicated.DeveloperEmail subject line testerCheck a subject line for length, spam triggers and the things that actually suppress open rates.MarketingEmail, URL and phone extractorPull every email address, link, phone number or figure out of a block of messy text.TextFavicon generatorProTurn any image into the full set of favicon sizes, plus the HTML to drop into your head.DesignFind and replaceReplace text across many lines at once, with optional regular expressions and case sensitivity.TextFreelance hourly rate calculatorWork backwards from the salary you want to the rate you must charge, once unpaid time is honest.BusinessGoogle and social previewSee how your page title and description will look in Google results and when shared, before you publish.MarketingGrowth rate (CAGR) calculatorTurn a start and end figure into the compound annual growth rate, and project it forward.BusinessHash generatorGenerate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes of any text, in your browser.DeveloperHMAC signature generatorGenerate an HMAC signature for webhook verification and signed API requests.DeveloperHreflang tag generatorProGenerate the hreflang tags that tell Google which language and region each version of a page serves.MarketingHTML entity encoderEscape characters that break HTML, or decode entities back into readable text.TextHTML to plain textStrip the tags out of HTML and get readable plain text, with paragraphs and line breaks kept.TextHTTP status code referenceLook up what an HTTP status code means and what you should actually do about it.WebImage resizer and converterProResize, compress and convert images to WebP, JPEG or PNG — entirely in your browser, nothing uploaded.DesignInvestment appraisal — NPV and IRRJudge a project properly: net present value, internal rate of return and discounted payback.BusinessInvoice and quote calculatorTotal up line items with tax, a discount and a deposit, and see exactly what is due now.BusinessInvoice due date calculatorWork out when an invoice is actually due under net terms, end-of-month terms or a fixed number of days.BusinessJSON formatter and validatorFormat, validate and minify JSON, with the exact position of any syntax error.DeveloperJSON to CSV converterFlatten an array of JSON objects into a CSV you can open in Excel or Google Sheets.DeveloperJWT decoderDecode a JSON Web Token to read its header and claims, and see whether it has expired.DeveloperKeyword density checkerSee which words and phrases dominate a page, and whether anything is repeated suspiciously often.TextLate payment interest calculatorWork out the statutory interest owed on an overdue invoice, day by day.BusinessLine break and whitespace cleanerFlatten text copied out of a PDF, collapse double spaces and strip trailing whitespace.TextList to SQL, JSON or CSVTurn a pasted column into a quoted SQL IN clause, a JSON array or a delimited line.DeveloperLoan repayment calculatorSee the monthly payment on a loan and, more importantly, what it costs you in total interest.BusinessMarkdown to HTMLConvert Markdown into clean HTML you can paste into a CMS or an email template.TextMeeting cost calculatorPut a figure on a recurring meeting — salary cost per hour, per occurrence, and per year.BusinessMileage and fuel cost calculatorWork out what a journey actually costs in fuel, and what you can claim back per mile or kilometre.BusinessNumber base converterConvert a number between binary, octal, decimal and hexadecimal, in both directions.DeveloperNumber to words converterSpell out a number in English — for cheques, contracts and invoices.DataOpen Graph and Twitter card generatorGenerate the meta tags that control how your page looks when it is shared on social media.MarketingPassword generatorGenerate strong random passwords or passphrases, with a real estimate of how long they resist cracking.DeveloperPassword strength checkerTest how long a password would resist an offline attack, entirely in your browser.WebPayment schedule builderSplit a project fee into a deposit and milestones, and see exactly what is invoiced when.BusinessPercentage calculatorEvery percentage question in one place: X% of Y, what percent, percentage change, and reverse percentages.BusinessPlaceholder text generatorGenerate lorem ipsum paragraphs, sentences or words for mock-ups and layout testing.TextProfit margin and markup calculatorWork out margin, markup and profit from cost and price — and stop confusing the two.Businesspx, rem and em converterConvert between pixels, rem, em and points against your root font size.DesignQuery string parserBreak a URL into its parts and read every query parameter as a table.DeveloperRandom number and pickerDraw random numbers, shuffle a list or pick winners fairly — with a cryptographic random source.DataReadability checkerScore your writing for reading age, and find the sentences making it hard work.MarketingRedirect map generatorTurn a list of old and new URLs into redirect rules for Apache, Nginx or a Next.js config.DeveloperRegular expression testerTest a regular expression against sample text and see every match and capture group.DeveloperRobots.txt generatorGenerate the file that tells search engines what to crawl, including the AI crawlers you may want to block.MarketingROI and payback calculatorJudge whether a spend paid for itself: return on investment, payback period and annualised return.BusinessRoman numeral converterConvert numbers to Roman numerals and back, with proper validation of malformed numerals.DataSalary and hourly rate converterConvert between annual salary, monthly pay, day rate and hourly rate, both directions.BusinessSales commission calculatorWork out commission on flat or tiered rates, including accelerators above target.BusinessSocial and ad character counterCheck one piece of copy against every platform limit at once, from a tweet to a Google Ads headline.MarketingSort and deduplicate linesSort lines alphabetically or by length, reverse them, and strip duplicates or blank lines.TextSQL formatterFormat a one-line query into something readable, with the major clauses on their own lines.DeveloperStatistics calculatorMean, median, mode, standard deviation and quartiles from a list of numbers.DataStock reorder point calculatorWork out when to reorder and how much to hold, so you neither run out nor tie up cash in a warehouse.BusinessTemperature converterConvert between Celsius, Fahrenheit and Kelvin, with the reference points that matter.DataText comparisonCompare two versions of a text line by line and see exactly what was added and removed.TextText reverserReverse text by character, by word or by line — useful for testing and for puzzles.TextText, hex and binary converterConvert text to hexadecimal, binary or decimal byte values, and back again.DeveloperTime duration calculatorAdd up hours and minutes, work out elapsed time, and convert a total into decimal hours for invoicing.DataTime zone converterSee what a given time is in other parts of the world, using real time zone rules including DST.DataTrue cost of an employeeSalary is rarely the real number — add employer contributions, benefits, equipment and holiday cover.BusinessUnit converterConvert length, weight, volume, area, speed and data sizes, with exact conversion factors.DataUnix timestamp converterConvert between Unix timestamps and human dates, in seconds or milliseconds, UTC or local.DeveloperUptime and SLA calculatorTurn an uptime percentage into the downtime it actually permits — per day, month and year.BusinessURL encoder and decoderPercent-encode text for use in a URL, or decode an encoded URL back to something readable.DeveloperURL slug generatorTurn a headline into a clean, lowercase URL slug with accents folded and punctuation removed.TextUUID generatorGenerate cryptographically random version 4 UUIDs, one or a thousand at a time.DeveloperVAT and sales tax calculatorAdd tax to a net price or pull it back out of a gross one — the direction people most often get wrong.BusinessWhat slow pages cost youPut a number on it: estimate the orders and revenue a slow-loading site loses you every month.BusinessWord and character counterCount words, characters, sentences and paragraphs, with a reading time and a readability score.TextWorking day calculatorAdd or subtract working days from a date, skipping weekends and any holidays you list.DataXML sitemap generatorProTurn a list of URLs into a valid XML sitemap, with priorities and change frequencies.Marketing