Know what the number actually means before you buy.
SpecPlain turns confusing consumer-tech labels into practical decisions. We explain the standard, show the math where it matters, and tell you what a specification does not guarantee.
Standards first
Technical claims are checked against standards bodies, program administrators, and manufacturer datasheets whenever possible.
Show the calculation
When a number can be derived directly, we explain the formula and provide a small browser-side calculator instead of hiding the logic.
Limits included
A connector shape or version label often tells only part of the story. We call out the missing conditions that can change compatibility.
Start with the specifications people regularly misread
Monitor dimensions: turn diagonal inches into real width and height
See why two displays with the same diagonal can have different physical dimensions, then calculate the panel size yourself.
DisplaysPixel density: resolution is only half the physical sharpness story
Calculate PPI from resolution and screen size, then see what the number can and cannot tell you about a display.
HDRDisplayHDR 400, 600, 1000 and True Black: what the tier really tests
Separate small-area peak brightness from sustained full-screen output, black level, color gamut and local-dimming requirements.
USB-CUSB-C cables: the connector does not tell you the capability
Separate data speed, charging power, and display support so you know what to check on a cable label.
USB-C displaysWhy some USB-C ports drive monitors and others do not
Follow the compatibility chain from host port to DisplayPort Alt Mode or USB4, cable, dock, and display instead of trusting connector shape.
ChargingUSB-C charger wattage: source capability, device request, cable limit
Understand USB Power Delivery negotiation and why a larger wattage printed on a charger does not force that power into every device.
HDMIHDMI cable categories: what 18, 48, and 96 Gbps actually describe
Use official cable categories instead of vague reseller language, and understand when higher bandwidth matters.
DisplayPortDP54, DP80 and UHBR: decode the high-bandwidth cable labels
Separate DisplayPort version numbers from UHBR link rates and VESA cable certification, including what happened to DP40.
StorageWhy a 1 TB drive can appear as about 931 GiB
The drive did not lose space. Decimal and binary units are different. Here is the conversion and what formatting changes afterward.
Data ratesMB/s vs Mb/s: the capital B changes the unit by a factor of eight
Convert network-style bit rates into storage-style byte rates without mistaking a theoretical link rate for real payload throughput.
Transfer timeEstimate how long a file transfer should take
Match GB with MB/s or Mb/s, calculate an ideal lower bound, and keep interface ceilings separate from sustained payload speed.
SD & microSDSD speed classes: separate V30 from UHS-I and peak read speed
Decode C10, U1, U3, V30, V60, V90 and SD Express class markings, then match the class and bus interface to the host device.
BatteriesCR2025 vs CR2032: same diameter and voltage, different thickness
Decode the physical size and compare manufacturer specifications before treating two coin cells as interchangeable.
What this site will not do
For the source hierarchy and calculation rules behind these guides, see Sources and methodology.