Measure
Use a device label, system reading, service manual, or documented display mode.
CALCULATED, NOT BENCHMARKED
3C Compass
Open models for charging, battery energy, device storage, laptop capacity, and USB-C display links. Enter measurements, inspect the arithmetic, then verify the hardware-specific limit.
I know the primary and simultaneous device demand in watts.
Open modelWORKED ENERGY PATH
20,000mAh is not 20,000mAh at the USB output
Rated cell energy74Wh
Estimated usable62.9Wh
Three 15Wh charges45Wh
Calculate
Keep inputs, intermediate values, rounding, and the model version visible.
Verify
Check the port table, host limit, airline rule, replaceability, or manufacturer specification.
FIVE OPEN MODELS
Start with the quantity that can be measured
No account, paywall, product ranking, or retailer exit is required.
Power budgetUSB-C charger
- Inputs
- Primary watts, simultaneous load, headroom, ports
- Output
- Total budget, market tier, primary-port minimum, cable class
- Inputs
- Printed mAh, cell voltage, efficiency, battery Wh
- Output
- Rated Wh, usable Wh, recharge count, reserve or shortfall
- Inputs
- Current used space, measured growth, months, reserve
- Output
- Projected use, retail tier, headroom, reserve threshold
- Inputs
- Peak memory, sustained swap, storage growth, replaceability
- Output
- Memory tier, storage tier, irreversible configuration choice
- Inputs
- Pixels, refresh, color depth, lanes, DisplayPort class
- Output
- Stream demand, payload, utilization, check state
CALCULATED EXAMPLES
Same functions, named scenarios
These are reproducible calculations, not physical test results. The complete registry and CSV live in the Lab.
Open all scenarioscharger100W tier65W laptop plus 20W phoneThe total label is useful only when the charger's two-port allocation preserves 65W for the laptop.power-bank31.45Wh usable10,000mAh weekend phone reserveThe printed mAh number overstates energy delivered at the USB output because conversion has a cost.phone-storage256GB tierSix-month measured storage trendA measured 128GB user can still justify 256GB when retained growth and an update reserve are projected across ownership.laptop-capacity24GB / 1000GBMeasured office and creative laptopSustained swap makes the memory requirement visible, while replaceable storage can take the later upgrade risk.display-link96.77% payloadDual 4K 60Hz over four HBR3 lanesThe uncompressed estimate nearly fills HBR3, so exact timing, DSC, host display count, and dock routing must be checked.
SUPPORTING MANUALS
Use prose where a formula cannot finish the decision
Manufacturer limits, diagnostic order, seller accountability, and inspection steps still need context.
Decision manualRAM / SSDcapacity plan
How Much RAM and Storage Does a Laptop Need in 2026?
Choose laptop memory and storage from your real workload, upgrade options, and ownership period instead of paying for capacity that never improves daily performance.
Decision manualWpower budget
USB-C Charger Wattage and Compatibility Guide
Match USB-C chargers and cables to phones, tablets, and laptops by understanding USB Power Delivery, wattage negotiation, ports, cable ratings, and proprietary fast charging.
Decision manualCHECKarrival record
Refurbished Electronics Buying Checklist
Reduce the risk of buying refurbished phones, laptops, tablets, and accessories by checking seller accountability, grading, battery health, locks, warranty, and returns.
Decision manualGBgrowth forecast
128GB vs 256GB Phone Storage: Which Is Enough?
Choose phone storage from your photo habits, offline media, app size, cloud plan, and expected ownership period instead of paying for unused capacity or managing a full device every month.
Decision manualWhenergy budget
Power Bank Rules for Flights: The Capacity You Can Actually Take Onboard
Choose enough portable power without creating an airport problem. Translate capacity into watt-hours, check airline limits, and match USB-C output to the devices in your bag.
Decision manualP / D / Vcapability record
USB-C Cable Labels Are a Trap: Wattage, Data, and Video Are Different Purchases
A USB-C cable can charge fast, move data slowly, or fail to run a monitor. Decode power, data, video, and e-marker claims before buying the wrong cable.
Decision manualGbpsdisplay link
USB-C Dock Not Detecting Two Monitors? The Problem Is Usually Not the Monitor
A dual-monitor dock can fail because of the laptop's display limit, the USB-C port, the dock chipset, the cable, or the monitor mode. Diagnose the weak link before buying another adapter.
METHOD BOUNDARY
Models are inspectable; hardware support is still model-specific
3C Compass is owner-operated. Calculations use stated assumptions and documented constraints. No page claims laboratory testing, product ownership, or measurement that did not occur.