SwiftMultiTool — Free Online Tools, Converters & Calculators

SwiftMultiTool is a collection of more than 50 free online tools, converters and calculators that run instantly in your browser. There is no sign-up, no installation and no cost — every tool delivers immediate results. Whether you need to count words for an essay, generate a strong password, convert currencies, format JSON, look up DNS records or create a QR code, SwiftMultiTool brings them together in one fast, mobile-friendly place.

Word & Language Tools

Text manipulation, word analysis and language utilities for writers, students and marketers.

Time & Date Tools

Time zone conversion, date calculations and time management utilities.

• Time Zone Converter — compare times across world time zones
• Date Calculator — add or subtract dates and find durations
• Timer & Stopwatch — count down or count up with precision
• Sleep Calculator — find the best bedtime based on sleep cycles

Math & Unit Converters

Mathematical calculators and unit conversion tools for everyday and technical use.

• Unit Converter — length, weight, temperature, volume, area, speed and more
• Currency Converter — live exchange rates between world currencies
• Mortgage Calculator — calculate monthly mortgage payments
• Percentage Calculator — discounts, tips, increases and decreases
• Scientific Calculator — advanced math and trigonometric functions
• GPA Calculator — compute grade point average
• Citation Generator — create APA, MLA and Chicago citations
• Fuel Efficiency Converter — MPG to L/100km and back
• Precious Metal Weight Converter — grams, ounces and troy ounces
• Energy & Power Converter — joules, watts and kilowatt-hours
• Speed, Force & Pressure Converter
• Light, Radiation & Sound Converter
• Mechanics & Chemistry Converter

Quick Image Utilities

Image processing and generation tools that run entirely in your browser.

• Image Converter — convert between PNG, JPG and WebP
• Favicon Generator — create favicons from any image
• Bulk Image Resizer — resize many images at once

Developer & Programming Tools

Tools for coding, formatting and development workflows.

• JSON Formatter — format, validate and beautify JSON
• Base64 Encoder/Decoder — encode and decode Base64 strings
• JWT Decoder — inspect JSON Web Token headers and payloads
• Cron Job Generator — build and explain cron expressions

Data & Formatting Engines

Convert and format data structures between common formats.

• JSON to CSV Converter — transform JSON data into spreadsheet CSV
• SQL Formatter — beautify and indent SQL queries
• Regex Tester — test regular expressions with live matches
• Markdown to HTML — convert Markdown into clean HTML
• URL Encoder/Decoder — encode and decode URLs safely
• HTML Entity Identifier — encode and decode HTML entities
• Lorem Ipsum Generator — generate placeholder text

Privacy & Networking Tools

Security and network utilities for developers and system administrators.

• DNS Lookup & WHOIS — query domain registration and DNS records
• DNS Record Generator — generate SPF, DKIM and other DNS records
• IP Checker — find your public IP address
• IP Range Checker — check public and private IP ranges
• Subnet Calculator — calculate subnets and CIDR ranges
• Port Checker — test whether a network port is open
• Hash Generator — generate MD5, SHA-1 and SHA-256 hashes
• API Key Generator — create secure random API keys
• UUID Generator — generate version 4 UUIDs
• Passphrase Generator — create memorable secure passphrases
• PIN Generator — generate random numeric PINs

Guides & Articles

Visit the SwiftMultiTool blog for in-depth guides on getting the most from these tools. Every article below has its own stable, crawlable page:

• The Word Count Targets That Actually Matter (And the Ones You Can Ignore) — Not every word limit carries the same weight. Here is which counts are enforced by software, which are enforced by humans, and how to hit them without rewriting your draft three times.
• Why Your Strongest Password Is One You Will Never Remember — The habits that make a password memorable are the same habits attackers model. Here is how to switch to generated credentials without making your daily life harder.
• Scheduling Across Time Zones Without the 3am Mistake — Daylight saving, half-hour offsets and date rollovers cause most cross-border meeting errors. A short guide to booking times your colleagues can actually attend.
• Discounts, Margins and the Percentage Mistake Almost Everyone Makes — Stacked discounts, reversed increases and the gap between margin and markup cost people real money. Here is the arithmetic behind each, in plain language.
• The Metric-to-Imperial Conversions Engineers Actually Use — Most conversion charts are padded with units nobody touches. These are the handful that appear in real drawings, specifications and purchase orders, and the rounding rules that keep them safe.
• Percentage Math for Real Life: Discounts, Tips, Raises, and Compound Changes — Percentages behave asymmetrically, and that asymmetry is where money leaks. A practical tour of stacked discounts, reversed increases, raises and compounding.
• The Real Math Behind Loan Amortization — Your monthly payment never changes, but what it buys you does. Understanding the split between interest and principal explains why early overpayments are so powerful.
• Calculating Exact Age Across Time Zones, Leap Years, and Calendars — Age looks like subtraction until a leap day, a time zone or a historical calendar reform gets involved. Here is what actually makes date arithmetic hard.
• Word Count Rules for Essays, SEO Content, and Social Media — Three writing worlds, three completely different relationships with length. Knowing which rules bind and which are folklore saves a great deal of pointless rewriting.
• Character Limits Explained: Twitter/X, Meta Descriptions, SMS — A character is not always one character. Encoding, emoji and pixel-width truncation mean the limit you are told is rarely the limit you get.
• Text Case Rules Real Editors Follow — Title case is not one rule but several competing ones, and sentence case has quietly won on the web. A short guide to choosing and applying a convention consistently.
• How Diff Algorithms Actually Compare Text — A diff does not know what you changed. It finds the smallest edit script that explains the difference, and understanding that explains every confusing diff you have ever read.
• Why Lorem Ipsum Exists and When to Use It — Placeholder text has a five hundred year history and a specific job: letting you judge layout without reading. It also causes real damage when it escapes into production.
• Debugging Malformed JSON: A Field Guide — Almost every JSON parse failure comes from the same short list of causes. Learn to recognise them from the error message and stop bisecting files by hand.
• Common Data Structure Pitfalls When Converting CSV to JSON — CSV is flat, untyped and barely standardised. JSON is nested and typed. Every conversion has to invent answers to questions the CSV never asked.
• What Base64 Actually Does — Base64 is not encryption, not compression and not obfuscation. It is a way of carrying binary data through systems that only accept text, and it always costs you a third more bytes.
• Hashing Explained: What MD5, SHA-1, and SHA-256 Are For — A hash is a one-way fingerprint, not encryption. Knowing which algorithm is broken, which is fine for integrity checks, and which belongs nowhere near a password.
• What Actually Makes a Password Strong in 2026 (Entropy, Not Just Length) — A long password is not necessarily a strong one. The real measure is entropy, the bits of uncertainty an attacker must search through, and it changes how you should generate and compare credentials.
• Why URLs Break Without Encoding (and What Each Special Character Means) — A space, an ampersand or a hash in the wrong place can silently break a link or split a query string. URL encoding exists to solve this, and the rules are simpler than they look.
• Regular Expressions for Beginners: The 10 Patterns That Solve 80% of Problems — You do not need to master the whole regex language to be productive. Ten patterns cover the bulk of validation, extraction and cleaning tasks you will actually meet.
• Markdown Syntax Quirks That Trip Up Beginners (and How Renderers Differ) — Markdown looks like plain text with a few symbols, but the spec has sharp edges: nested lists, indented code, line breaks and tables all behave differently across renderers.
• HEX, RGB, and HSL Explained: Choosing the Right Color Format for the Job — Three formats describe the same color in three different ways, and each one makes a different task easy. Picking the right format saves time when adjusting, matching or generating colors.
• CSS Gradient Techniques Beyond the Basics: Mesh, Conic, and Layered Gradients — A two color linear gradient is the start, not the end. With multiple color stops, conic gradients and layered backgrounds you can build depth, lighting and texture in pure CSS.
• Lossy vs. Lossless Image Compression: Choosing the Right Settings for Web Performance — Images are the heaviest part of most pages, and the compression choice you make decides both file size and visible quality. The right setting depends on the content, not a single rule.
• Image Dimensions and Aspect Ratios for Every Platform (Social, Web, Print) in 2026 — Every platform crops differently, and an image that looks perfect in one place is mangled in another. A reference to the dimensions and ratios that matter, and how to prepare one source image for all of them.
• Unix Timestamps Explained: Why Computers Count Time From 1970 (and How Time Zones Break Things) — A Unix timestamp is the seconds since midnight on 1 January 1970. It is elegant, timezone free and the source of a surprising number of bugs when humans get involved.
• True Randomness vs. Pseudo-Randomness: What Your Random Number Generator Is Actually Doing — The numbers your computer calls random are almost certainly deterministic, produced by an algorithm from a seed. That is fine for most purposes and dangerous for a few.
• QR Code Standards, Error Correction, and Why Your QR Code Might Not Scan — A QR code is not a single format but a family of versions with built in error correction. Understanding the levels and capacity limits explains why some codes scan reliably and others fail.
• Cron Syntax Demystified: Building Reliable Scheduled Tasks Without the Headaches — Five fields, a handful of operators, and a long list of subtle traps. A clear walkthrough of cron syntax, the environments it runs in, and the failures that catch people by surprise.
• Advanced Calculator Techniques: From Logarithms to Matrix Operations — A scientific calculator is more than arithmetic with extra buttons. Knowing what logarithms, exponents, trigonometry and matrix operations actually do unlocks the problems a basic calculator cannot touch.

About SwiftMultiTool

SwiftMultiTool is built to be fast, accessible and privacy-friendly. All calculations and conversions run client-side in your browser whenever possible, so your data never leaves your device. The site is mobile-friendly, works without an account, and is free for everyone. Read more on the About page, browse the FAQ, or contact us with questions.

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