Tools

Work out final amount and interest for a lump sum or monthly savings plan - year-by-year chart, time-to-target answer, German tax and inflation view.

Hypotenuse, general triangles, sine and cosine on the unit circle, prism and pyramid volumes - with a Pythagoras proof you can watch.

Calculate area, circumference, volume and surface area for a circle, cylinder, cone or sphere - with one drawing that shows how the four shapes connect.

Six modes in one tool: days between dates, human-readable duration, add or subtract, age, countdown, and German working days.

Project a lump-sum investment or an ETF savings plan in one tool. See the real TER drag in Euros, plus optional German Vorabpauschale tax for an honest after-tax estimate.

Which barcode does your product need? The generator recommends EAN-13, ISBN-13, Code 128, or ITF-14, shows the check-digit derivation, and flags whether the code still scans once printed.

Translate text to Morse code and back - with German umlauts, audio playback at your own speed, and a tap-input mode for practice.

Enter start and end times; the calculator applies Germany's statutory break (ArbZG § 4) automatically, flags overtime above 8 h, and shows your weekly-target gap.

A stylometric signal for text: three statistical components plus an honest limit. No percent score, no AI verdict, no promise the field cannot keep.

Compute PayPal fees both ways: gross to net, or what to invoice so net X arrives. Five modeled scenarios compared side by side.

Character counter for tweet, SMS, SEO title and meta description - with translator mode for standard pages at 1,500 and 1,800.

Plan meetings across time zones with named participants, per-person working hours, regional holidays, and DST shifts marked inline on the strip.

Type a cron expression and check it against Vixie, Quartz, AWS EventBridge, GitHub Actions and Kubernetes. Plain-language describe plus diagnostics for the documented footguns.

Diff checker with three modes - code, prose, and translation. Word-level granularity for prose, no whole-line-red.

Lorem ipsum generator with slot fitting (Button, H1, Meta) and live preview in a mock component. Plus a German layout-stress variant and a sourced length cheatsheet.

JSON Web Token (JWT) decoder with security checks. Flags what's off with your token: alg: none, expired, weak HS256 secret, PII in the payload.

Convert Markdown to HTML and see what each token actually produces - with a live spec-rule explainer and a visible GFM vs CommonMark switch.

Calculate aspect ratios and preview how your image fits Instagram, Open Graph or A4 - before you export, not after.

Bidirectional converter with strict validation (`VL → not valid; 45 = XLV`), derivation per conversion (`1984 = M + CM + LXXX + IV`), Year mode with verify-before-permanent share link, plus side-by-side Maya, Babylonian, Egyptian, and Greek-attic comparison. All in your browser.

Tip calculator with card-pad preview, service slider, pre-tax mode, service-charge check, travel norms, and per-person split.

Hash generator for 8 algorithms at once - SHA-2/3, BLAKE2/3, MD5. Status badges, avalanche demo, file hashing up to 50 MiB. Local in your browser.

Unix timestamp converter with 16 readings: Unix, ISO 8601 and 12 calendar/date notations - Julian Day, Mayan, Hijri, Thai Buddhist, Ethiopian, Indian Saka and more. Y2038 warning. Local in your browser.

Color converter for 6 spaces at once: HEX, RGB, HSL, OKLCH, LAB, Display-P3. With OKLCH lightness rotator and live WCAG meter. Local in your browser.

Percentage calculator with 6 modes - including percentage points vs percent and asymmetric loss-recovery. Live visualisation per mode, in your browser.

What's the name of a number with 33 zeros? 100 zeros? Convert any number to its name in 9 notations including English, Indian lakh/crore, Japanese, scientific. BigInt to 10^200.

UUID generator with a per-version layout diagram: v1, v3, v4, v5, v7 and ULID. v7 is sortable, v4 is random, v3/v5 are deterministic. All in your browser.

Base64 step by step: 3-byte groups as chips, 4-character blocks beside them, padding and URL-safe variant explained. Encode and decode in the browser.

Count working days in Germany 2025-2027. Pick your federal state, plan vacation in a 12-month grid, find the strongest bridge days. Output transfers to the hourly rate calculator.

JSON formatter, validator and sorter. Type chips for every field, tree view, caret-pointed error card with common-cause list.

QR code generator with capacity chips. Bytes, version, EC level and WCAG contrast in one view. Four modes (text, URL, vCard, Wi-Fi). No account.

Password generator with entropy explained. Length and charset size determine the bits, and the bits drive the strength label. Weak-password alert with one-click fix. No account.

URL encoding step by step: every %-code colour-coded and explained, double-encoding alert, encode and decode in the browser.

German VAT calculator. 19 or 7 percent, gross-to-net or net-to-gross, quick reference for reduced-rate goods, custom EU rate. Runs in browser, no signup.

Calculate your net salary in Germany for 2026. Lohnsteuer, Soli, health, pension, tax-class comparison. No signup.

Calculate a freelancer hourly rate with target income, working days, overhead, and utilisation. DACH defaults, no signup.