Online Tools for Everyone

Fast, free tools right in your browser. No sign-up, no data sent to servers — everything runs locally.

Cryptography & Hashing

Hash Generator (MD5, SHA-1, SHA-256, SHA-512)

Compute MD5, SHA-1, SHA-256, SHA-384 and SHA-512 from any text — all algorithms in one tool, entirely in your browser.

JWT Decoder

Decode JSON Web Tokens and instantly inspect header, payload and claims like exp and iat.

Password Generator

Strong passwords and Diceware passphrases with strength meter — cryptographically random.

WordPress Password Hash Generator

Generate WordPress password hashes and verify existing hashes against passwords.

JWT Generator

Generate signed JSON Web Tokens (HS256/384/512).

UUID Generator

UUIDs (v4, v7, v1, NIL) up to 1000 at once in multiple formats.
Encoding & Decoding

Base64 Encoder/Decoder

Encode and decode text and files to/from Base64. Supports UTF-8 and data URIs.

JSON Formatter

Format, minify and validate JSON with precise error location.

JSON Editor

Powerful JSON editor with tree, text and table view, schema validation, diff, query and conversion.

XML Editor

XMLSpy-style XML editor: fully editable tree view, XPath, XSLT, XSD validation and generation.

URL Encoder/Decoder

Encode and decode URLs and text components. With explanation of reserved characters.

YAML ⇄ JSON

Convert YAML to JSON and back — entirely in your browser.

CSV ⇄ JSON

CSV to JSON and back — with delimiter choice and header detection.

Markdown → HTML

Convert Markdown to HTML live with GFM syntax and XSS protection.
Text Tools

RegEx Tester

Test regular expressions live with match highlighting, capture groups and syntax reference.

Lorem Ipsum Generator

Generate placeholder text: Lorem Ipsum and filler text in multiple languages. By paragraphs, words or characters.

Word Counter

Words, characters, sentences, paragraphs, reading time — all live.

Case Converter

camelCase, snake_case, kebab-case and 11 more formats.

Slug Generator

SEO-friendly URL slugs with diacritic handling and stop-word filter.
Date & Time

Unix Timestamp Converter

Live current Unix time, convert dates to Unix timestamps and Unix timestamps to readable dates.

Date Difference Calculator

Days between two dates, age calculator, working days, or add/subtract days.

World Clock & Meeting Planner

Live clocks for cities worldwide, 24h meeting slider with work-hours overlay.

Countdown Timer

Live countdown to New Year, Christmas, birthday or any custom date.

Age Calculator

Exact age in years, months, days — plus days until next birthday.

Cron Generator

Build cron expressions visually, parse them and check next runs.
CSS Tools

CSS Gradient Generator

Create linear and radial CSS gradients visually with live preview and copy the generated code.

CSS Border-Radius Generator

Visually adjust rounded corners — individual corners, elliptical radii, with live preview.

CSS Box-Shadow Generator

Create CSS box shadows visually: multiple shadows, offset, blur, spread, inset — with live preview.
Design & Colors

Color Converter

Convert colors: HEX, RGB, HSL, CMYK. Generate palettes: complementary, analogous, triadic.

Material Design Colors

All Material Design colors as interactive palette. Click to copy, CSS variables, download the CSS file.

Contrast Checker

Check WCAG AA/AAA contrast with live preview.
Calculators

Percentage Calculator

Calculate percentages: X% of Y, X is what % of Y, percentage change.

BMI Calculator

Calculate Body Mass Index with WHO category classification. Metric and Imperial.

Unit Converter

Convert units: length, weight, temperature, area, volume, speed, digital data.

TDEE & BMR

Daily calorie needs by Mifflin-St Jeor — with cutting and bulking targets.

Tip Calculator

Calculate tip and split the bill between people.

Loan Calculator

Amortizing loan: monthly payment, interest and total cost.

IBAN Calculator & Validator

Calculate and validate IBANs, find BIC + bank

Compound Interest

Wealth growth with compound interest and monthly contributions.

VAT Calculator

Add or strip VAT — with quick-select common rates.

Bauspar vs. Savings plan

Compare a German Bausparvertrag with an ETF savings plan over the full term, with chart.

Real Hourly Wage

What's truly left per hour after commute, lunch and work clothes?

Heating Comparison

Heat pump vs. gas vs. oil vs. pellets: 20-year cost comparison with chart.

Caffeine Calculator

When's your last coffee so your sleep is undisturbed?

Schengen 90/180

How many days can you still stay in Schengen? Multi-trip calculator.

DE Property Tax

German transfer tax + notary + land register + broker in one go.

Personal Inflation

Your real inflation rate based on your own spending basket.
Web & Dev

HTTP Status Codes

Quick lookup of all HTTP status codes with explanation.

LLM API Cost

Compare Claude, GPT, Gemini & DeepSeek API pricing side by side.

AI Token Counter

Estimate tokens for Claude, GPT-4o, GPT-4 and Gemini at a glance.
Media & Social

QR Code Generator

QR codes for URLs, Wi-Fi, vCards, email and SMS — customizable colors and size.

YouTube Thumbnail Downloader

View and download YouTube thumbnails in all resolutions. Just paste the URL.
Kitchen & Home

Recipe Scaler

Scale cooking recipes to any servings, convert baking pans and cups to grams.
PHP

PHP date() & strtotime()

Interactive reference: test format strings live, look up parameters and try strtotime() expressions.
Outdoor & Maps

Dog Map

OSM map with poop bag dispensers, bins, vets and dog-friendly zones. Live GPS and GPX export.

Lifesaver — AED Map

Find the nearest defibrillator instantly. With emergency-call button and directions.

E-Mobility Map

EV chargers and EV-only parking with kW filter, plug type and navigation.

Kids Map

Playgrounds and changing tables, with age, shade and fencing filters.

Drinking Water Map

Skip plastic bottles — free drinking fountains and water taps near you.

Bike Map

Repair stations, pumps, rentals and covered parking for cyclists.

Camping Map

Campsites, motorhome pitches, and sanitary dump stations.

Swimming Map

Bathing lakes, outdoor and indoor pools with lifeguard info and prices.

Farmers' Market Map

Farmers' markets and farm shops with opening hours and organic labels.

Accessibility Map

Wheelchair-friendly places with traffic-light status: full/limited/no access.

Recycling Map

Recycling centers and containers with material filter (glass, paper, plastic, e-waste).

Climbing Map

Climbing gyms, boulder halls, and outdoor crags with difficulty grade and route count.

Book Lover Map

Bookshops, libraries, and public bookcases — buy, borrow, swap.

Postal Map

Mailboxes with collection times, parcel lockers, post offices and pickup shops.

Why CalcSI?

Ready Instantly

No registration, no login. Just open and start using.

Responsive

Works on desktop, tablet and smartphone — anywhere, anytime.