Tech
How DNS propagation time is estimated
Learn what DNS propagation time really means, how to estimate it from TTL and cache windows, and what the calculator can’t know.
Aug 4, 2026 · 5 min read
Category
Tech
The tools, gadgets, AI, and software shaping how we live and work.
27 tools · 31 articles
Free Tech tools
DNS Propagation Time Calculator
Estimate how long DNS changes may take to fully reach users worldwide.
Open the tool →Battery Life Calculator
Runtime from capacity and draw - and why a 10,000 mAh power bank only delivers about 6,660 mAh at the USB port.
Open the tool →Cloud Storage Cost Calculator
Storage is the cheap part. Compare a standard tier against an archive one once retrieval and egress are counted, and find the crossover.
Open the tool →Colour Contrast Ratio Calculator
The WCAG contrast ratio for any two colours, checked against all four thresholds - plus whether plain black or white text would do better.
Open the tool →Monthly Data Usage Calculator
Where your gigabytes actually go - and why the video quality setting matters more than everything else on the list combined.
Open the tool →Password Entropy Calculator
Entropy in bits, and how long a password survives a given attack - as long as it was chosen randomly, which is the assumption doing all the work.
Open the tool →Memory Card Capacity Calculator
How many photos fit on a card - and why half an hour of 4K video costs you more of it than eight hundred RAW frames.
Open the tool →Print Size and DPI Calculator
How big you can print an image before it softens - and why 300 dpi is only the right answer for something held in your hands.
Open the tool →PSU Wattage Calculator
What power supply a build needs - sized for transient spikes rather than the sum, and for the load where a PSU is actually most efficient.
Open the tool →RAID Rebuild Time Calculator
How long a replacement drive takes to rebuild, how much data must be read to do it, and what the drive's own error spec says about the odds.
Open the tool →RAID Usable Capacity Calculator
How much of your array you actually get to use, what the OS will report instead, and the cost of every terabyte that survives.
Open the tool →TV Viewing Distance Calculator
How far to sit, from the published viewing-angle standards - and the separate distance at which you would stop seeing pixels.
Open the tool →Uptime SLA Downtime Calculator
What each 'nine' actually costs you in minutes - and why 99.99% is a different engineering problem rather than a slightly better one.
Open the tool →Video Bitrate Calculator
The bitrate that hits a target file size - with the audio track subtracted, because it comes out of the same budget and people forget it.
Open the tool →Aspect Ratio Calculator
Resize without distorting: give the original dimensions and one new one, get the other back. Plus the ratio as a decimal, which is the number worth learning.
Open the tool →Case Converter
Paste text once and get UPPERCASE, lowercase, Title Case and Sentence case together - no mode to pick, nothing sent anywhere.
Open the tool →Download Time Calculator
How long a file takes at your connection speed - including the conversion nearly everyone gets wrong, because megabits and megabytes differ by eight.
Open the tool →File Size Converter (GB to MB)
Both answers, side by side. A 1 TB drive really does hold a trillion bytes - and Windows really does call that 931 GB. Neither is lying.
Open the tool →Find and Replace (Online)
Literal find and replace - deliberately not regex, so a pattern can never hang your browser and what you type means itself.
Open the tool →JSON Formatter & Validator
Paste JSON and get it indented and minified at once - and if it is broken, the parser's own error with the line and column.
Open the tool →Line Sorter & Deduplicator
Sort and de-duplicate a list - with the cleaned version shown too, because raw de-duplication misses "apple" and "apple " and always will.
Open the tool →PPI & Screen Size Calculator
Pixel density from a screen's diagonal and resolution, plus its real width and height - because a bigger 4K panel can be less sharp than a smaller 1440p one.
Open the tool →URL Slug Generator
Turns a headline into a clean URL slug - and shows you the shortened version too, because the best slug is usually not the whole title.
Open the tool →Text Cleaner
Trim every line, drop the blanks, remove duplicates - all four results at once, in your browser, on lists that have been through three programs.
Open the tool →URL Encoder & Decoder
Both directions at once, so you never pick the wrong one - and it encodes the component-safe way, which is the one you almost always want.
Open the tool →Base64 Encoder & Decoder
Paste text or Base64 and get both forms at once. Runs entirely in your browser — nothing is uploaded.
Open the tool →Password Generator
Strong random passwords generated in your browser, at four lengths. Nothing is sent anywhere and nothing is stored.
Open the tool →Tech articles
Tech
How Big Can I Print This Photo?
300 dpi isn't a standard — it's the answer for arm's length. At ten feet, a 24 MP file covers seventeen feet of wall.
Aug 3, 2026 · 4 min read
Tech
How Far Should You Sit From Your TV?
Two different questions with two different answers — and at 4K they stopped agreeing. At nine feet you can go from a 69-inch screen to a 138-inch one.
Aug 3, 2026 · 4 min read
Tech
How Long Does a RAID Rebuild Take?
Rebuilding one 8 TB drive means reading 40 TB off the survivors. The read is five times the write, and it's the part that carries the risk.
Aug 3, 2026 · 4 min read
Tech
How Many Photos Fit on a Memory Card?
Half an hour of 4K costs you about 850 RAW frames. If any video goes on the card, it decides the answer and the photos are the remainder.
Aug 3, 2026 · 3 min read
Tech
How Much Space Do You Actually Get From RAID?
Six 4 TB drives gives you 24 TB, 20, 16, 12 or 4 depending on the level. Price it per usable terabyte and the choice gets much easier.
Aug 3, 2026 · 4 min read
Tech
How Strong Is Your Password Really?
'P@ssw0rd123!' scores 79 bits here and would fall in seconds. The entropy formula only describes passwords a machine chose.
Aug 3, 2026 · 4 min read
Tech
How to Check Colour Contrast Properly
Pure blue text on white passes AAA. Pure green fails everything. Green carries ten times blue's weight in the WCAG formula, and it shows.
Aug 3, 2026 · 4 min read
Tech
What Bitrate Do I Need for This Video?
Size divided by time — then take the audio out. Skipping that one step is why a file lands just over the upload limit.
Aug 3, 2026 · 3 min read
Tech
What Does 99.9% Uptime Actually Mean?
43 minutes a month. And the jump to 99.99% isn't a stricter version of the same problem — it's a different problem.
Aug 3, 2026 · 4 min read
Tech
What Is Actually Using Your Data Allowance?
One hour of 4K uses as much as a hundred hours of music. Switching quality changes your month by more than any habit will.
Aug 3, 2026 · 3 min read
Tech
What Size Power Supply Do I Actually Need?
Adding up the wattages gives the wrong answer twice over — transient spikes go above it, and efficiency peaks at half load.
Aug 3, 2026 · 4 min read
Tech
Why Cheap Cloud Storage Is Not Cheap
Moving a terabyte out costs about what storing it for four months costs. If your data leaves regularly, the storage rate barely matters.
Aug 3, 2026 · 4 min read
Tech
Why Your Power Bank Holds Less Than It Says
A 10,000 mAh pack delivers about 6,660 mAh at the USB port. The label isn't dishonest — it's measured at a different voltage.
Aug 3, 2026 · 3 min read
Tech
Find and Replace Without Regex
Search for 3.14 and you get 3.14 — not 3x14. Every character means itself, which is both what you wanted and the reason it can't hang your browser.
Jul 31, 2026 · 4 min read
Tech
How Long Will My Download Take?
Your 100 Mbps connection moves 12.5 MB/s. If that gap surprises you, it's the reason your downloads look eight times slower than the plan you're paying for.
Jul 31, 2026 · 3 min read
Tech
How to Calculate Aspect Ratio
Learn the decimal, not the colon. 1.7778 against 1.5 tells you which is wider instantly — 16:9 against 3:2 makes you do arithmetic first.
Jul 31, 2026 · 3 min read
Tech
How to Change Text Case (Without Retyping It)
UPPERCASE, lowercase, Title Case and Sentence case side by side — plus the two things every automatic converter gets wrong, and what to fix by hand.
Jul 31, 2026 · 4 min read
Tech
How to Clean Up a Messy List
Trim first — not because of blank lines, but because a deduplicate that runs too early removes almost nothing while looking like it worked.
Jul 31, 2026 · 4 min read
Tech
How to Format and Validate JSON
Formatted and minified at once — and when it's broken, how to translate the parser's error into the character that actually caused it.
Jul 31, 2026 · 3 min read
Tech
How to Sort and Deduplicate a List
De-duplication compares raw strings, so 'apple' and 'apple ' both survive. Trim first — or you get a worse answer that looks correct.
Jul 31, 2026 · 4 min read
Tech
How to Write a Good URL Slug
Lowercase, hyphens, and shorter than the title. And never change a published one without a redirect — the slug IS the page's address.
Jul 31, 2026 · 3 min read
Tech
How URL Encoding Works (And Which Encoder You Actually Want)
Encode 'salt & pepper' with the wrong encoder and the server reads it as two parameters. That single confusion causes a large share of all URL bugs.
Jul 31, 2026 · 3 min read
Tech
What Is PPI, and Does It Actually Matter?
A 43-inch 4K screen is less sharp than a 27-inch 1440p one. Resolution is a pixel count — sharpness is how thinly those pixels are spread.
Jul 31, 2026 · 3 min read
Tech
Why Your 1 TB Drive Shows as 931 GB
The drive holds a trillion bytes, exactly as advertised. Windows divides by 1,024³ and prints 'GB' where the standard name is 'GiB'. Nothing is missing.
Jul 31, 2026 · 3 min read
Tech
How to Choose a Strong Password
Length beats complexity, uniqueness beats both, and rotating every 90 days makes things worse. What actually protects an account, and why.
Jul 30, 2026 · 5 min read
Tech
What Base64 Actually Is (And What It Isn't)
Base64 turns any data into 64 safe characters so it survives text-only channels. Here's how it works, why it's 33% bigger, and why it is not encryption.
Jul 30, 2026 · 4 min read
Tech
Cloud 3.0 Is the Real 2026 IT Story
The next cloud shift is less about moving workloads and more about controlling AI, data, and cost. That’s why Cloud 3.0 matters.
Jul 23, 2026 · 5 min read
Tech
Why AI Security Platforms Matter in 2026
AI is moving into the core of business software, and that makes security messier, not cleaner. AI security platforms are the boring answer to a real problem.
Jun 20, 2026 · 5 min read
Tech
AI Agents, Explained: From Chatbots That Answer to Software That Does
Everyone's saying "AI agents" in 2026. Here's what they actually are, why it's a genuine shift, and where they already work — in plain English.
Jun 19, 2026 · 4 min read
Tech
The AI Tools Actually Worth Your Time in 2026
Everyone's shipping an AI app. Here are the few that genuinely save you hours every week — and the ones to skip.
Jun 18, 2026 · 1 min read