· 5 min read
What Are PPI and DPI? Pixel Density for Screen and Print
PPI and DPI both measure density per inch, but one is about screens and the other about print. Learn how to compute pixel density and what Retina really means.
Articles by Daniel Okonkwo
Front-end developer and tech writer · View profile
· 4 min read
What Is a Break-Even ROAS? (And How to Find Yours)
ROAS is revenue divided by ad spend. Learn what break-even ROAS means, how to find it from your profit margin, and why a ROAS above 1 can still lose money.
· 4 min read
Screen Resolutions Explained: 1080p, 1440p, 4K
What 1080p, 1440p, and 4K really mean. Learn how resolution counts pixels, why total pixels grow so fast, and how aspect ratio ties width to height.
· 4 min read
What Is Bitrate? Bits per Second, CBR vs VBR
Bitrate is how many bits of data a video or audio stream uses each second. Learn how it sets quality and file size, and the difference between constant and variable bitrate.
· 4 min read
Retail Markup and Keystone Pricing: How to Set Your Price
Learn how retail markup works, why keystone pricing doubles cost, and the crucial difference between markup and margin — so you set prices that actually cover your costs.
· 4 min read
What Is Inventory Turnover? (And What's a Healthy Ratio)
Inventory turnover shows how many times you sell through your stock in a year. Learn the formula — COGS divided by average inventory — and what a healthy ratio looks like.
· 5 min read
How to Estimate Video File Size (Bitrate x Duration)
Estimate any video's file size before you export. Learn the bitrate-times-duration formula, why you divide by 8, and how resolution and frame rate change the result.
· 4 min read
CPM, CPC and CPA Explained: Which Ad Metric Matters?
Understand cost per mille, cost per click and cost per acquisition — how each is calculated, how they relate, and which one to optimize for at each stage of a campaign.
· 4 min read
How to Find Your Break-Even Point (With the Formula)
Learn the break-even formula — fixed costs divided by contribution margin — and work out exactly how many units you must sell before you start making a profit.
· 4 min read
How Many Photos Fit on a Memory Card? Photos, Songs, and Video
Estimate how many photos, songs, or hours of video fit on a card by dividing its capacity by the average file size.
· 4 min read
How Much Data Streaming Uses: SD, HD, and 4K per Hour
See how many gigabytes per hour SD, HD, and 4K video use, and how to check a monthly streaming habit against a data cap.
· 4 min read
What Is Customer Churn Rate? Formula and How to Reduce It
Customer churn rate measures how fast you lose customers. Learn the formula, why it caps growth and shortens lifetime value, and how to reduce it.
· 4 min read
How Much Internet Speed Do You Need? A Household Guide
Work out the internet speed your home needs by adding up Mbps per video stream, video call, and gamer, with clear examples.
· 3 min read
What Is Average Order Value (AOV)? Formula and How to Raise It
Average order value measures how much a customer spends per order. Learn the formula, why it matters for profitability, and proven ways to lift it.
· 3 min read
WebP vs JPG vs PNG: Which Image Format Should You Use?
JPG, PNG and WebP each win in different cases. Here is when to use each for the best balance of quality, file size and compatibility.
· 4 min read
How to Price a Product: Cost-Plus, Markup vs Margin, and Value-Based
A practical guide to pricing: work out your unit cost, apply cost-plus pricing, understand markup versus margin, and know when to price on value instead.
· 4 min read
How Subnet Masks Work: CIDR, Network Bits, and Usable Hosts
Understand how a subnet mask splits an IP address into network and host parts, what /24 means, and how to count usable hosts.
· 4 min read
How to Read Binary and Convert It to Decimal and Hex
Learn how binary place values work and convert binary to decimal and hexadecimal by hand, with clear worked examples.
· 3 min read
What Is Customer Lifetime Value (LTV)? Formula and Uses
Customer lifetime value estimates the total worth of a customer over the whole relationship. Learn the formula, why margin matters, and how to use it.
· 3 min read
How to Create a Strong Password
Length beats complexity. Here's why a four-word passphrase is strong, why you should never reuse a password, and how a manager makes it effortless.
· 3 min read
How to Compress an Image Without Losing Quality
Smaller images load faster and rank better. Here's how to shrink an image the smart way — format, resolution and compression level — without visible loss.
· 3 min read
What Is Customer Acquisition Cost (CAC)? Formula and Benchmarks
Customer acquisition cost tells you what it really costs to win a new customer. Learn the formula, what to include, and how to read it against lifetime value.
· 2 min read
JSON vs XML: What's the Difference?
JSON and XML both store structured data as text, but they trade off differently. Here's how each looks, where each wins, and how to choose.
· 2 min read
What Is Base64 Encoding?
Base64 turns binary data into safe text. Here's what it does, why it exists, why it isn't encryption, and the size cost it adds.