21 free tools, with more on the way
Free online tools
that just work.
Security checks, network tests, generators and calculators for IT pros, businesses and anyone else who needs a job done. No sign-up, no paywall.
- Tools
- 21+
- Cost
- £0
- Sign-ups
- None
- Categories
- 5
Spotlight
Flagship tools
The tools we're building first, all designed for speed and privacy.
Secure Shared Clipboard Transfer
Move text, passwords and snippets between devices with end-to-end encryption and links that expire on their own.
Smart QR Code Generator
QR codes for links, Wi-Fi, contacts and more, in your own colours, as PNG or SVG.
Cyber Essentials Checker
Answer guided questions to see how ready your organisation is for UK Cyber Essentials certification.
Internet True Line Capacity Speed Test
Measure real download, upload, latency and jitter to see what your line can actually deliver.
The toolbox
All tools
Search or filter by category. New tools are added regularly.
21 of 21 tools
Secure Shared Clipboard Transfer
Move text, passwords and snippets between devices with end-to-end encryption and links that expire on their own.
Cyber Essentials Checker
Answer guided questions to see how ready your organisation is for UK Cyber Essentials certification.
Password Generator
Strong random passwords and memorable passphrases, generated in your browser.
Password Strength Tester
See how long a password would take to crack. It never leaves your device.
Email Security Checker
Check a domain's SPF, DKIM and DMARC records and spot spoofing risks.
SSL Certificate Checker
Inspect a site's certificate, its expiry date, the full chain and the TLS versions it supports.
Hash Generator
Create SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or files.
Internet True Line Capacity Speed Test
Measure real download, upload, latency and jitter to see what your line can actually deliver.
What's My IP
Your public IPv4 and IPv6 addresses and connection details at a glance.
DNS Lookup
Look up A, AAAA, MX, TXT, NS, CNAME and SOA records for any domain.
Subnet Calculator
Work out network ranges, masks, broadcast addresses and usable hosts.
HTTP Header Checker
See the response headers, redirect chain and security headers for any URL.
Smart QR Code Generator
QR codes for links, Wi-Fi, contacts and more, in your own colours, as PNG or SVG.
UUID Generator
Generate v4 and v7 UUIDs one at a time or in bulk.
JSON Formatter & Validator
Pretty-print, minify and validate JSON with clear error messages.
Base64 Encoder / Decoder
Encode text and files to Base64, or decode them back.
Unix Timestamp Converter
Convert between Unix time and readable dates in any time zone.
Colour Converter & Contrast
Convert between HEX, RGB and HSL, and check WCAG contrast between two colours.
UK VAT Calculator
Add or remove VAT at 20%, 5% or a custom rate.
Download Time Calculator
Find out how long a file will take to transfer at a given line speed.
Percentage Calculator
Percentages of numbers, percentage change, increases and decreases.
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Show all toolsWhy osir
Built by IT pros, free for everyone
Free, for good
Every tool is free to use. There are no trials, credits or premium tiers.
No sign-up
Open a tool and use it. No accounts, emails or passwords.
Private by design
Where possible, tools run in your browser, so your data never leaves your device.
Fast and lightweight
Hand-written code with no bloated frameworks or trackers. It works on any device.
Brought to you by
Made possible by our partners
osir's free tools are built and supported by three technology companies.