All Tools
Every tool we make. Free, browser-based, no account required.
The catalog keeps growing. Developer utilities for formatting, validating, and converting. Design tools for color, type, gradients, and favicons. Home and DIY calculators for paint, drywall, flooring, framing, and garden beds. Everyday essentials covering finance, privacy, statistics, and health. New tools ship every few weeks. Search what's here, or jump to a category to see what's already in your corner.
Paste. Compare. Copy the diff.
Semantic diff for JSON & YAML with color-coded comparison and copyable plain-text summaries.
Try it 02The Unix timestamp converter that tells you what you're looking at.
Auto-detects seconds, milliseconds, microseconds, or nanoseconds. Multi-format output with one-click copy.
Try it 03The jq playground developers actually keep open.
WASM-powered jq execution with shareable permalinks, curated examples, and persistent query history.
Try it 04The fastest, cleanest JSON formatter online.
Instant beautify and minify with syntax highlighting, error positions, and one-click copy.
Try it 05See exactly which cron field is wrong, and why.
Field-level cron validation with human-readable schedule descriptions and next execution dates.
Try it 06Hex math that shows its work in every base.
Hex calculator with arithmetic and bitwise operations, plus live output in hex, decimal, octal, and binary.
Try it 07Paste a messy table. Get a perfect one. Instantly.
Markdown table formatter with live preview and correct CJK wide-character alignment.
Try it 08Build an RBAC matrix. Export it anywhere.
Checkbox-grid permission matrix generator with export to CSV, Markdown, and JSON. No spreadsheet required.
Try it 09CSV to JSON in one paste.
Auto-delimiter detection, four JSON output modes, pretty-print or compact, download or copy.
Try it 10Format SQL in seconds, right in the browser.
14 SQL dialects, keyword case controls, indentation options, and a unique before/after diff view.
Try it 11Token count, cost, and context window for GPT, Claude, and Gemini.
Multi-model token counter with cost estimation, context window usage, and live stats. Everything runs in your browser.
Try itEvery composition guide, on any photo, in your browser.
Overlay a golden spiral, phi grid, golden triangle, or rule-of-thirds guide on any image you upload — instant, non-destructive composition analysis in the browser tab you already have open.
Try it 02Your favicon set, dark-mode ready, in 90 seconds.
Favicon package generator producing dark-mode-ready SVG favicons and cross-platform icon sets, fully processed in the browser.
Try it 03CSS text gradients with real fonts and real color science.
A client-side CSS text gradient generator with Google Fonts, OKLCH color, and a live typography preview. Copy production-ready CSS in under a minute.
Try it 04CSS gradients with Tailwind output and OKLCH color quality.
Visual gradient builder with perceptual color space interpolation, Tailwind-native code output, and one-click copy.
Try it 05Drop an image, paste a :root.
Image-to-palette extractor with CSS custom properties, Tailwind v3/v4 output, JSON design tokens, and a WCAG contrast pairings matrix.
Try it 06Convert colors instantly. Copy in one click.
HEX, RGB, HSL, and CMYK conversion in real time with a session color history that persists across page refreshes.
Try it 07Contrast ratio, instantly clear.
WCAG 2.2 + APCA contrast checker that shows the closest on-brand fix for failing color pairs and generates shareable permalinks.
Try it 08Hit space. Get colors that actually pass.
Spacebar-fast, accessibility-first color palette builder. WCAG 2.1 AA/AAA and APCA scored on every pair, with plain-language coaching and CSS / Tailwind v4 export.
Try it 09Font pairings that explain themselves.
Curated heading/subheading/body trios from Google Fonts with plain-language explanations of why each pairing works.
Try itThe honest ceramic coating cost and payback calculator.
Free, no-signup ceramic coating calculator — coverage, real DIY-vs-pro cost, and the month it pays for itself, in under a minute.
Try it 02Accurate drywall sheets in seconds.
Drywall sheet estimator with door/window deductions, accessories breakdown, and cost estimate in under 60 seconds.
Try it 03Know exactly how many boxes to buy.
Flooring calculator for hardwood, laminate, LVP, tile, and carpet with smart waste defaults per material type and cost estimates.
Try it 04Know exactly how much mulch you need. Instantly.
Cubic yard and bag count estimates for garden beds. Enter dimensions, pick depth, get your shopping list.
Try it 05The wallpaper roll calculator that prints your shopping list.
Per-wall wallpaper roll calculator with door and window deductions, pattern match handling, a waste slider, and a printable shopping list.
Try it 06Compost ratios in plain language — not just a C:N number.
A mobile-first compost calculator that turns carbon-to-nitrogen math into plain-language recipes: "add 2.5 buckets of dried leaves to reach 28:1."
Try it 07Mark your studs right the first time.
Stud spacing calculator with a printable layout template showing exact stud positions. The output no competitor offers.
Try it 08Know exactly what to buy before you hit the paint aisle.
Accent wall paint calculator with door/window subtraction, cost estimates at three price tiers, and a printable shopping list.
Try itThe compound interest calculator that doesn't get in your way.
Drag sliders, watch your money grow. Real-time compound interest with a stacked growth chart and a full year-by-year breakdown.
Try it 02See what your photos are hiding, then strip it.
In-browser metadata removal for JPEG, PNG, WebP, and HEIC. Preview GPS, device IDs, and timestamps before wiping them in one click.
Try it 03COGS, gross profit, and margin in one calculation.
Enter inventory and costs, get COGS, gross profit, gross margin, and a step-by-step formula breakdown instantly.
Try it 04Compress unlimited images without a single upload.
Browser-only batch image compressor with a live before/after slider, unlimited queue, and zero network requests.
Try it 05Density, mass, volume — solved and explained.
Three-variable calculator with unit conversion across 24 units, step-by-step breakdowns, and a material reference table.
Try it 06The clean APR↔APY converter — your answer in 10 seconds.
Bidirectional APR↔APY converter with eight compounding frequencies, live results, and the formula always in plain sight — free of funnels and clutter.
Try it 07Every down payment scenario, side by side.
Compare 3%, 5%, 10%, and 20% down payments with real PMI costs, monthly payments, and total cash needed at closing.
Try it 08Test statistic in, p-value out. 30 seconds.
P-value calculator for Z, T, chi-square, and F distributions with tail selection and plain-English significance interpretation.
Try it 09Am I intoxicated? How long until I'm sober?
BAC calculator with custom ABV per drink, color-coded results against the legal limit, and an estimated time-to-sober countdown.
Try itThe shrink number Ugly's leaves out — front and center, in one glance.
Free conduit offset and 3-point saddle calculator for electricians. Pick a trade angle, enter the rise, and read your mark spacing plus the shrink to add back — with shrink as the hero output — in under 15 seconds.
Try it 02Cut crown molding right the first time.
Free crown molding compound miter calculator that gives exact saw miter and bevel angles for any spring angle and real wall corner, plus a diagram showing how to orient the piece on the saw.
Try it 03Read the stick, get the gallons.
A free, mobile-first calculator that turns a horizontal-tank dipstick reading into gallons remaining and gallons to fill.
Try it 04Tension per sling leg, from a tape measure — not a protractor.
Free no-account sling tension calculator. Enter height and leg length — no protractor — and read tension per leg, the tension factor, and a color-coded danger warning in under 30 seconds.
Try it 05Know how far your blade runs past the line — before the first cut.
A free calculator that tells stone and concrete cutters exactly how far a large-diameter circular blade overruns the cut line — with bevel and reverse safe-depth modes and a live side-profile diagram.
Try it 06The ramp length you need — and whether you'll drag your belly getting up it.
A free, vendor-neutral ramp calculator that solves the length you need for a safe loading angle — and gives a plain-language breakover verdict on whether a low vehicle will high-center at the transition.
Try itHow these tools are built
Every tool on AppCrib is a static site that ships to your browser once and runs there. No servers hold your data, because the tools don't need servers. Paste JSON into jsonr, strip EXIF from a photo in Blank, measure a wall in Drywl. All of it runs in your tab. Nothing leaves. That's not a marketing pose. It's the only technical model that can credibly promise your data stays yours.
It also makes everything fast. No spinners, no queue, no cold-start latency dragging a 400ms round trip onto a one-second calculation. Input changes, output updates, done.
The standard they share
Every tool uses the same design system. Same type scale, same color logic, same dark mode, same spacing grid. Someone who's used jqbin already knows how to use Rolemat without reading a tutorial. That's the point of shipping many small tools instead of a handful of large ones. Consistency is a feature, and building it once means every new tool inherits it.
Same privacy model across the catalog. Same performance bar. Same refusal to block the interface with modals or sign-up walls.
Browse by category
Each category has its own landing page where the tools are grouped with a bit more context on what they're for. The lineup in each one keeps expanding.
- Developer Tools11 tools
Formatters, validators, converters, and playgrounds. Every one runs in your browser, respects your data, and doesn't look like it was built in 2008.
- Design Tools9 tools
Color, contrast, type, gradients, and favicons. The small tools designers and front-end developers reach for every week, finally done well.
- Home & DIY Tools8 tools
Paint, drywall, flooring, studs, mulch. The calculators that tell you exactly what to buy before you drive to the store.
- Everyday Tools9 tools
Finance calculators, privacy tools, statistics utilities, and health checks. Everyday tools that don't need a login or a subscription.
- Field Math6 tools
Cut angles, conduit bends, sling loads, tank fills. Field calculators for carpenters, electricians, riggers, and haulers who need the number, not a spreadsheet.
New tools ship regularly
The catalog grows every few weeks. We spot a gap in the free-tool landscape and ship something that fills it. Launch notes and technical deep-dives live on the blog, which is the best way to follow along without checking back here.