Every Tool on OCXLY, Explained

Pricing for large language models changes constantly, and the cost of a single feature can swing 10× depending on which model you pick. The LLM Cost Calculator lets you punch in input and output token counts for GPT, Claude, Gemini, and other tiers, then compare the totals side by side. Every price is editable, so when a vendor moves a number you can update it without waiting for us. It's the first thing to open before you commit a feature to a particular model.

The Prompt Builder scaffolds structured LLM prompts using the role / task / context / examples / format / constraints pattern, then exports them in plain text, Markdown, or XML style. It's designed to take the guesswork out of prompt engineering — instead of staring at an empty box, you fill in named fields and the tool assembles a clean, model-friendly prompt for you.

Token costs are real money. The Token Counter gives you a BPE-aware estimate of how many tokens a piece of text will consume, using real pre-tokenisation plus byte-calibrated subword counting. Paste a draft prompt or document and you'll know — before you call the API — roughly what it will cost and whether it fits the context window.

The Base64 tool encodes plain text or files to Base64, decodes Base64 back to its original form, and supports URL-safe mode for tokens and query parameters. Useful for inspecting JWTs, embedding small assets in data URIs, debugging API payloads, or moving binary through text-only channels — all live, in-browser.

Sleep happens in roughly 90-minute cycles, and waking mid-cycle is the difference between feeling rested and feeling wrecked. The Sleep Calculator works in both directions: tell it when you need to wake up and it suggests bedtimes aligned to complete cycles; tell it you're going to bed now and it tells you the best times to set an alarm. Simple, gentle, and one of the most consistently useful tools we ship.

The BMI Calculator accepts metric or imperial input and returns your Body Mass Index alongside the WHO category breakpoints and a healthy-weight range for your height. BMI is a coarse indicator, not a verdict — we present the number with that context, so you can use it as a single data point rather than a label.

The JSON Formatter validates and beautifies JSON with syntax highlighting and inline error detection. Paste an API response, a tangled config file, or a one-line minified payload and it becomes legible immediately. When the JSON is broken, the tool tells you exactly where — line and character — so you can fix it instead of guessing.

The Regex Tester gives you live matching with real-time highlighting, named capture groups, replace preview, and toggleable flags. A built-in JavaScript regex cheatsheet sits beside the editor for when you forget which escape does what. Build the expression, watch it match, then copy it back into your codebase with confidence.

Naming things is hard; converting between naming styles shouldn't be. The Case Converter handles 16 cases — UPPERCASE, lowercase, Title Case, camelCase, PascalCase, snake_case, kebab-case, dot.case, slug-form, and more — instantly. Paste a list of identifiers, pick a target style, copy the result.

The Pomodoro Timer implements the classic 25-minute work / 5-minute break cycle with longer rest after four sessions, tracks your progress through the day, and stays calm and uncluttered while it runs. Open the tab, start the timer, and let the structure carry you through whatever you were avoiding.

The Date & Age Finder calculates the days between any two dates, ISO week numbers, and an exact age in years, months, and days. Flexible date formats mean it works for contracts, birthdays, project timelines, and trivia alike — whenever you need a precise interval and don't want to fight a spreadsheet.

The Markdown Editor is a distraction-free writing surface with live preview, a syntax toolbar for people who don't memorise Markdown, auto-save, and one-click export to HTML or .md. Draft a blog post, a README, or a long email and ship it from the same tab.

The Word Counter counts words, characters (with and without spaces), sentences, and paragraphs in real time, and lets you set a target so you know exactly how far you have to go. Useful for writers chasing a brief, developers writing release notes, or anyone fighting a character limit.

Clear writing is measurable. The Readability Analyser scores your text against Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and ARI, then shows you a sentence-by-sentence difficulty map. Wherever the heatmap turns red, that's where readers stumble — rewrite there first.

Placeholder text doesn't have to be boring. The Lorem Ipsum Generator ships five flavours — Classic Latin, Tech, Space, Nature, and a Neuro variant — and lets you generate by paragraphs, sentences, words, or even bytes. Export as plain text, HTML, or Markdown straight into your mockup.

The PDF to Word Converter turns PDF files into editable .docx documents entirely in your browser, preserving text and heading structure. Because the conversion happens locally, sensitive contracts and personal documents stay on your machine — no upload, no cloud queue, no waiting.

The PDF Splitter lets you carve a large PDF into smaller ones by page ranges or extract individual pages as standalone files. Great for trimming an invoice out of a statement, separating chapters from a textbook, or peeling a single signed page out of a 100-page contract.

The PDF Merger is the other half of the splitter: drag in multiple PDFs, reorder them, and combine them into a single document. Everything happens client-side, so you can merge confidential pages without uploading them anywhere.

Typography looks expensive when the sizes follow a consistent ratio. The Type Scale Generator builds harmonious scales using musical ratios — minor third, perfect fourth, golden ratio, and more — previews heading and body sizes side by side, and exports the result as CSS custom properties you can drop straight into your stylesheet.

The Scientific Calculator handles trigonometric, logarithmic, exponential, and power functions, swaps between degrees and radians, and keeps a history of your previous calculations so you can scroll back through your working. It's the always-open second tab you didn't realise you needed.

The Base Calculator converts numbers between binary, octal, decimal, hexadecimal, Base-32, Base-36, and any custom base from 2 to 36. A bit visualiser shows you the underlying binary representation, and the reference table makes it useful as a teaching tool as well as a working one — handy when you're debugging bitwise logic or learning how computers actually count.

The Unit Converter covers more than 20 categories — length, mass, temperature, area, volume, speed, data, pressure, energy, time, and many more. Whether you're translating recipes, sizing storage, or comparing engineering specs in different systems, it answers the question without making you hunt for the right tab.

The Loan Calculator works out monthly payments, total interest, and full amortisation schedules for any kind of loan — mortgage, auto, or personal — with adjustable term and rate. Use it to stress-test what an extra percentage point would cost you, or to see how much faster you'd pay off the principal by adding £50 to each payment.

The Image Compressor shrinks JPEG, PNG, and WebP files in-browser. Adjust the quality slider, resize the dimensions, convert between formats, and download the result without uploading the original anywhere. Ideal for getting page images under a budget or preparing photos for email without losing them to a cloud service.

The Watermark Generator adds text or logo watermarks to your images — tiled across the surface, on a diagonal, or in a single corner — with adjustable opacity, size, and rotation. Everything happens locally, so client work and personal photos never leave your laptop.

The Colour Palette Generator takes a single seed colour and builds palettes using eight harmony rules — complementary, analogous, triadic, tetradic, split-complementary, and three monochromatic variants. Copy any swatch as HEX, RGB, or HSL, and export the whole palette as CSS variables, JSON, or SVG with 10-step shade scales.

The Color Blindness Simulator shows how your designs appear to people with protanopia, deuteranopia, tritanopia, and other colour-vision deficiencies. Pair it with the contrast checker below and you have most of the accessibility kit you need before signing off a colour decision.

The Contrast Checker measures the contrast ratio between two colours and tests it against the WCAG AA and AAA thresholds for normal and large text. Use it whenever you're picking a foreground / background pair — it's faster than guessing, and the result is auditable.

The Focus Soundscape mixes ambient sound and binaural beats for focus, meditation, and deep-work sessions. The presets are tuned for neurodivergent users in particular — long-form, low-stimulation textures that fade into the background instead of demanding your attention.

The Breathing Timer is an animated guide for box breathing, 4-7-8, the physiological sigh, coherent breathing, and extended exhale. Each pattern comes with short, science-backed notes on what it's good for, so you can pick the right technique for the state you're in — sleep, focus, or rapid stress recovery.

Galaxy Chess is two-player live chess over a shared 5-digit key. Create a game, share the code with your opponent, and play in real time — no account, no app install, just a link and a board.

The Reaction Time Test measures how fast you respond to a visual cue across five rounds and returns your average, best, and worst times alongside percentile benchmarks. Useful as a quick caffeine check, a fatigue indicator, or a friendly competition.

The Stroop Test is the classic colour-word interference task — read the word, name the colour, watch your brain stumble. It tracks accuracy and reaction time per trial, making it a fun and surprisingly informative measure of attention and cognitive flexibility.

Treat this page as an index. Bookmark it, search it with Ctrl/⌘ + F, and jump straight to the tool you need. If you'd rather browse visually, the tools page presents the same set as a grid grouped by division, with a search box at the top.

Everything you see here is free, free of accounts, and free of tracking beyond the basic privacy-respecting analytics described in our privacy policy. If a tool is missing, broken, or you wish it did something it doesn't, write to [email protected] — we read every message, and most of the tools on this page exist because someone asked.