What does this tool check?

It performs a real TLS handshake to the domain on port 443 — the same connection your browser makes. It extracts the certificate the server actually presents, along with the TLS version, cipher suite, and certificate chain. This shows exactly what a visitor to the site would see.

Why does it show a different certificate than other tools?

Some tools query Certificate Transparency (CT) logs, which contain every certificate ever issued for a domain — including expired and revoked ones. This tool connects directly to the server and shows only the certificate currently in use.

What does the certificate chain show?

The chain shows how trust is established: from the leaf certificate (issued to the domain) through one or more intermediate Certificate Authorities up to a trusted root CA. A complete chain is required for browsers to trust the certificate.

SSL Certificate Checker

About SSL Certificate Checker

Performs a live TLS handshake to port 443 and extracts the certificate currently served by the domain. Shows the subject, issuer, validity dates, days until expiration, SHA-256 fingerprint, serial number, Subject Alternative Names (SANs), TLS protocol version, cipher suite, and the full certificate chain from leaf through intermediates to the root CA.

Connects directly to the server — shows the actual live certificate, not historical logs
Displays TLS protocol version (TLS 1.2, TLS 1.3) and negotiated cipher suite
Full certificate chain visualization from leaf to root CA
Expiration color-coded: green (>30 days), amber (1–30 days), red (expired)
SHA-256 fingerprint and serial number with copy buttons
Subject Alternative Names (SANs) listed for multi-domain certificates

Frequently Asked Questions

What does this tool check?: It performs a real TLS handshake to the domain on port 443 — the same connection your browser makes. It extracts the certificate the server actually presents, along with the TLS version, cipher suite, and certificate chain. This shows exactly what a visitor to the site would see.
Why does it show a different certificate than other tools?: Some tools query Certificate Transparency (CT) logs, which contain every certificate ever issued for a domain — including expired and revoked ones. This tool connects directly to the server and shows only the certificate currently in use.
What does the certificate chain show?: The chain shows how trust is established: from the leaf certificate (issued to the domain) through one or more intermediate Certificate Authorities up to a trusted root CA. A complete chain is required for browsers to trust the certificate.

Affiliate Recommendation

SSLs.com

SSL certificates made simple, from $3.44/yr

Get started free

This is an affiliate link. We may earn a small commission at no extra cost to you. We only recommend products we genuinely find useful.

More Networking & IT Tools

All Networking & IT tools

Networking & IT

Network Diagnostics

Analyze your network connection with DNS speed tests, latency measurement, WebRTC detection, and browser capability checks.

Networking & IT

Hosting Checker

Identify the web hosting provider, CDN, DNS, and email service for any domain.

Networking & IT

CIDR Aggregator

Summarize a list of IPv4 addresses and CIDR blocks into the minimal set of aggregated CIDR routes.

Networking & IT

Website Speed Test

Server-side performance analysis with DNS/TCP/TLS/TTFB timing waterfall and security header audit.

All Tools

Calculators

Age Calculator — Calculate exact age in years, months, days, and hours from birth date.
Arithmetic Calculator — Basic calculator for add, subtract, multiply, divide.
Aspect Ratio Calculator — Calculate, convert, and lock aspect ratios for images, video, and screen resolutions.
Bandwidth Calculator — Calculate bandwidth needs for transfers and streaming.
Battery Bank Calculator — Calculate battery bank capacity and configuration for solar power systems.
Body Surface Area Calculator — Calculate body surface area from height and weight.
Concrete Calculator — Calculate how much concrete you need for a project.
Date Calculator — Find days between dates or add/subtract time.
Discount Calculator — Calculate sale prices and savings from percentage discounts.
Electrical Power Calculator — Calculate watts, volts, amps, and electricity costs.
Electricity Cost Calculator — Estimate how much an appliance costs to run.
Fabric Calculator — Calculate how much fabric you need for a project.
Freelancer Rate Calculator — Calculate what to charge based on income goals.
Fuel Economy Calculator — Calculate MPG or L/100km from distance and fuel used.
Graphing Calculator — Plot mathematical functions and equations on a graph.
IP Address Calculator — IPv4 subnet calculator: network, broadcast, mask, host range, special-use scope, binary, and subnet splitting.
IPv6 Subnet Calculator — IPv6 subnet calculator: network range, expand/compress, bit-accurate address type, reverse DNS, and subnet splitting.
Lawn Size Calculator — Calculate lawn area for fertilizer and seed quantities.
Meeting Cost Calculator — Calculate how much a meeting costs based on attendee salaries.
MTU Calculator — Find optimal MTU size for your network.
Ohms Law Calculator — Calculate voltage, current, resistance, or power using Ohm's law.
Ovulation Calculator — Estimate ovulation and fertile window dates.
Paint Calculator — Calculate how much paint you need for walls or rooms.
Percentage Calculator — Find percentages, percent change, and what percent X is of Y.
Pregnancy Calculator — Calculate due date and pregnancy milestones.
Recipe Nutrition Calculator — Calculate calories and macros for a recipe.
Resistor Color Code Calculator — Decode resistor values from color bands.
Solar System Sizing Calculator — Size a solar panel system for your energy needs.
Standard Deviation Calculator — Calculate mean, variance, and standard deviation.
Surround Sound Setup Calculator — Calculate speaker placement for surround sound.
Time Zone Calculator — Convert times between different time zones.
Unit Price Calculator — Compare prices per unit to find the best deal.

Converters

Binary Text Converter — Convert text to binary and binary to text.
CIDR to IP Range Converter — Convert CIDR notation to IP address ranges.
Color Code Converter — Convert colors between hex, RGB, HSL, and CMYK.
CSV to JSON Converter — Convert CSV data to JSON format.
Data Storage Converter — Convert between bytes, KB, MB, GB, TB, and more.
JSON to CSV Converter — Convert a JSON array of objects to CSV — nested keys flattened, columns merged, values RFC-4180 escaped.
JSON to YAML Converter — Convert between JSON and YAML in both directions, with auto-detection — for configs, pipelines, and manifests.
Markdown to HTML Converter — Convert Markdown to HTML.
Number Base Converter — Convert numbers between binary, octal, decimal, hexadecimal, and any custom base 2–36.
Roman Numeral Converter — Convert between Roman numerals and regular numbers.
Time Converter — Convert between hours, minutes, seconds, and more.
Unit Converter — Convert length, weight, temperature, and other units.
URL Encoder Decoder — Encode and decode URL strings.

Date & Time

Countdown Timer — Count down to any date or event.
Stopwatch — Stopwatch with lap times.
World Clock — See current time in cities around the world.

Development

Codec Detector — Detect audio/video codecs and check browser support.
Cron Expression Builder — Visually build cron expressions by clicking checkboxes and dropdowns — no syntax memorization required.
Cron Job Tester — Test cron expressions and see upcoming run times.
Environment Variable Manager — Edit and export environment variables (.env files).
Hash Generator — Generate MD5, SHA-1, SHA-256, and other hashes.
HTML Editor — Write HTML with live preview side by side.
JSON Formatter — Prettify, minify, and validate JSON.
JSON Schema Validator — Validate JSON against a JSON Schema.
JSON to Go Struct — Generate Go structs with json tags from a JSON sample — nested types, slices, and omitempty inferred.
JSON to TypeScript — Generate TypeScript interfaces from a JSON sample — nested types, optional keys, and unions inferred.
JSON Validator — Check if JSON is valid and find syntax errors.
JWT Decoder — Decode JWTs and view header, payload, and claims.
Regex Pattern Explainer — Explain what a regex pattern does in plain English.
Regex Tester — Test regex patterns with live highlighting, named & numbered capture groups, and a replace/substitution preview.
SQL Formatter — Format and beautify SQL queries with syntax highlighting and indentation.
Unix Timestamp Converter — Convert Unix timestamps to human-readable dates and dates back to Unix timestamps in seconds or milliseconds.
XML Formatter & Validator — Format, minify, and validate XML with error highlighting.
YAML Validator — Validate YAML syntax and find errors.

Educational

Flashcard Maker — Create flashcards for studying and memorization.
Grade Calculator — Calculate grades and what you need on finals.
Typing Speed Test — Test your typing speed and accuracy.

Finance

Breakeven Calculator — Calculate breakeven point, margin, and target profit.
CAGR Calculator — Calculate compound annual growth rate from start and end values.
Compound Interest Calculator — Calculate compound interest with contributions over time.
Currency Exchange Rate History — View historical exchange rates between currencies.
Depreciation Calculator — Calculate asset depreciation with yearly schedules.
Expense Splitter — Split bills among friends with uneven shares.
Loan Amortization Calculator — Generate loan payment schedules with principal/interest split.
Mortgage Calculator — Calculate monthly payments and total interest on a mortgage.
Paycheck Calculator — Estimate take-home pay after taxes and deductions.
Retirement Calculator — Project retirement savings and estimate if you're on track.
ROI Calculator — Calculate return on investment percentage and profit.
Rule of 72 Calculator — Estimate how long to double your money at a given rate.
Sales Tax Calculator — Calculate sales tax amounts and totals for purchases.
Simple Interest Calculator — Calculate simple interest balances with clear principal, rate, and time breakdowns.
Tax Calculator — Estimate income tax based on brackets, deductions, and filing status.
Tip Calculator — Quickly split bills with tip percentages, rounding options, and per-person totals.

Gaming

Dice Roller — Roll dice of any type for tabletop games.

Gardening

Companion Planting Guide — Find which plants grow well together in your garden.
Gardening Planner — Plan garden layouts and planting schedules by zone.

Generators

Barcode Generator — Create barcodes in Code 128, EAN, UPC, and other formats.
Calendar Generator — Create printable monthly or yearly calendars.
Character Name Generator — Generate random character names by genre and origin.
Citation Generator — Generate citations in APA, MLA, Chicago, and other formats.
Color Palette Generator — Generate harmonious color palettes from a base color.
CSS Gradient Generator — Create linear and radial CSS gradients visually.
Favicon Generator — Create favicons from images in multiple sizes.
Git Command Generator — Build git commands with a visual interface.
Haiku Generator — Generate random haiku poems.
Invoice Generator — Create invoices with line items, tax, and totals.
Lorem Ipsum Generator — Generate placeholder Lorem Ipsum text by paragraphs or words.
Markdown Table Generator — Create Markdown tables visually.
Open Graph Tag Generator — Generate Open Graph meta tags for social sharing.
Passphrase Generator — Generate memorable word-based passphrases using a 2048-word dictionary and cryptographic randomness.
Password Generator — Generate random passwords with custom length and characters.
QR Code Generator — Create QR codes for URLs, text, WiFi, and contacts.
Random Number Generator — Generate random numbers within a range.
Random Quote Generator — Get random inspirational quotes by category.
Random Team Generator — Randomly divide people into teams.
Reverse Text Generator — Reverse text, words, or flip text upside down.
Unit Test Generator — Generate unit test boilerplate for functions.
Username Generator — Generate random usernames.
UUID Generator — Generate UUIDs in v1, v4, and other formats.

Health

BMI Calculator — Calculate your BMI from height and weight.
Body Fat Calculator — Estimate body fat percentage from measurements.
Calorie Calculator — Estimate daily calorie needs based on your stats.
Color Blindness Test — Test for color blindness with Ishihara plates.

Image Tools

EXIF Data Viewer — View EXIF metadata (camera, date, GPS) from images.
Image Compressor — Compress PNG, JPEG, and WebP images in your browser. No upload required.
Image Resizer — Resize images while keeping aspect ratio.

Language

Unicode Symbols Table — Browse and copy Unicode symbols and characters.

Media

Noise Generator — Play white, pink, or brown noise for focus or sleep.
Speech To Text Converter — Convert speech to text in real time.
Text to Speech — Convert text to speech with adjustable voice and speed.

Networking & IT

Browser Fingerprint Test — See what data websites can collect from your browser.
CIDR Aggregator — Summarize a list of IPv4 addresses and CIDR blocks into the minimal set of aggregated CIDR routes.
CIDR Overlap Checker — Find overlapping, duplicate, or contained CIDR blocks in a list — audit firewall, NSG, and route rules.
DNS Lookup — Query A, AAAA, MX, NS, TXT, SOA, CAA, SRV and reverse PTR DNS records over encrypted DNS-over-HTTPS.
Hosting Checker — Identify the web hosting provider, CDN, DNS, and email service for any domain.
IP Address Lookup — Display your public IP address, location, ISP, and network information.
Network Diagnostics — Analyze your network connection with DNS speed tests, latency measurement, WebRTC detection, and browser capability checks.
SSL Certificate Checker — Check the live SSL/TLS certificate for any domain — see validity, issuer, TLS version, cipher suite, and the full certificate chain.
VPN & Proxy Detector — Detect whether your connection is using a VPN or proxy, check for WebRTC leaks, and analyze DNS resolver.
Website Speed Test — Server-side performance analysis with DNS/TCP/TLS/TTFB timing waterfall and security header audit.
WHOIS Lookup — Look up domain registration details, expiry dates, registrar, and nameservers.

Productivity

Checklist Maker — Create and print checklists and to-do lists.
Meeting Time Finder — Find meeting times that work across time zones.
Online Notepad — Simple notepad that saves in your browser.
Online Whiteboard — Draw and sketch on a digital whiteboard.
Pomodoro Timer — Focus timer with 25-minute work sessions and breaks.
Weekly Schedule Planner — Plan your week with a visual schedule grid.

Reference

Greek Alphabet Chart — Greek letters with names, symbols, and pronunciation.
HTML Color Names — Browse all 140 named HTML colors with hex codes.
HTML Entities Reference — Reference table of HTML character entities.
HTTP Status Codes Table — Reference table of all HTTP status codes.
Morse Code Chart — Morse code reference for letters and numbers.
Phonetic Alphabet Chart — NATO phonetic alphabet (Alpha, Bravo, Charlie...).
SI Prefixes Table — SI unit prefixes from yocto to yotta.

Text Tools

Anagram Solver — Find all valid words from scrambled letters.
BBCode Editor — Edit BBCode with live preview for forum posts.
Markdown Editor — Write Markdown with live preview.
Markup Editor — Edit markup languages with syntax highlighting.
Morse Code Translator — Convert text to Morse code and back, with audio.
Palindrome Checker — Check if words, phrases, or numbers read the same forwards and backwards.
Readability Checker — Check reading level and readability scores for text.
Text Case Converter — Convert text between different cases: UPPERCASE, lowercase, Title Case, camelCase, etc.
Text Diff Checker — Compare two texts and highlight differences.
Text Repeater — Repeat any text or string a specified number of times with a custom separator.
Word Counter — Count words, characters, sentences, and paragraphs.
Word Rhyme Finder — Find words that rhyme with any word.

Utilities

API Response Formatter — Format and beautify JSON and XML API responses.
Business Jargon Translator — Decode corporate buzzwords into plain English.
CSS Minifier — Compress CSS by removing whitespace and comments.
JavaScript Minifier — Compress and minify JavaScript using Terser — mangle variables, strip comments, and reduce file size.
Password Strength Checker — Check how strong your password is.
PDF to Text Extractor — Extract text from any PDF file directly in your browser — no upload, no server, complete privacy.
QR Code Reader — Scan and decode QR codes from uploaded images.

Web Tools

Base64 Encoder Decoder — Encode and decode Base64 strings.
Color Accessibility Checker — Check if color combinations meet WCAG contrast requirements.
Color Picker — Pick colors and get hex, RGB, HSL values.
CSS Box Shadow Generator — Build and preview CSS box-shadow values with multiple layers, presets, and live preview.
HTML Encoder — Encode special characters as HTML entities.
HTTP Status Code Checker — Check any URL's HTTP status code and headers.
Image to Base64 Converter — Convert images to Base64 data URLs for direct embedding in HTML, CSS, or JSON.
Robots.txt Generator — Create robots.txt files for search engine control.
URL Parser — Break a URL into its parts — protocol, host, port, path, hash, and a decoded query-parameter table.