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.
Browse by the kind of specification you are trying to decode
Resolution, size, pixel density, refresh rate and HDR
Keep physical dimensions, raster size, timing and luminance separate instead of treating one display badge as a complete quality score.
ConnectionsUSB-C, USB4, Thunderbolt, HDMI and DisplayPort
Trace compatibility through the source, port, cable, adapter or dock, and display rather than trusting connector shape or a version name alone.
Storage & data ratesCapacity, interfaces, endurance, IOPS and transfer speed
Separate units, bus limits, workload conditions and sustained payload performance before comparing storage specifications.
BatteriesCell size, chemistry, nominal voltage and capacity labels
Use the full battery designation and manufacturer test conditions instead of assuming matching dimensions make two cells interchangeable.
Charging & energyUSB Power Delivery, PPS, EPR, watts and watt-hours
Distinguish source capability, device requests, cable limits, power rate and stored energy before using a headline watt number as a verdict.
Good starting points
4K vs UHD vs 2160p: 3840×2160 and 4096×2160
Separate the consumer 4K UHD raster from the DCI cinema container, then check what a “4K” label still leaves unspecified.
Refresh rate60Hz, 120Hz, 144Hz and 240Hz in milliseconds
Convert hertz into refresh interval while keeping refresh timing separate from FPS, pixel response and total latency.
USB-CUSB-C cables: the connector does not tell you the capability
Separate data speed, charging power and display support so two identical-looking USB-C cables are not treated as equivalent.
USB4 & ThunderboltUSB4 vs Thunderbolt 4 and Thunderbolt 5
Compare the shared USB-C connector with the different performance levels and certification requirements behind the names.
Storage interfacesM.2 vs NVMe vs SATA: form factor, protocol and bus are different
See why an M.2 label does not prove that an SSD is NVMe, and why physical fit alone does not settle storage compatibility.
SSD performanceIOPS vs MB/s: why both can describe the same SSD differently
Connect operations per second with block size and data rate while keeping queue depth, latency and access pattern attached to the benchmark.
Button cellsLR44 vs SR44: same size, different chemistry
Keep alkaline and silver-oxide chemistry, nominal voltage and unlike capacity-test conditions attached to the full battery designation.
AA batteries1.5V alkaline vs 1.2V NiMH AA batteries
Separate nominal voltage from loaded behavior, charging rules and device-specific compatibility before substituting a rechargeable AA cell.
USB Power DeliveryUSB-C charger wattage: source capability, device request, cable limit
Understand why a larger number printed on the charger does not force that power into every connected device.
USB PD rangesSPR vs EPR: where 100W, 140W, 180W and 240W come from
See how higher EPR voltages extend USB Power Delivery and why charger, device and cable support all have to line up.
What this site will not do
For the source hierarchy and calculation rules behind these guides, see Sources and methodology.