Compare charger options and a recharge deadline using the bank inputs on this page.
Battery & Power
Estimate power bank charging time
Compare the energy that must be stored with the usable charging power, then add an optional near-full finishing allowance.
Calculation breakdown
Estimate only. The calculator assumes the selected charger profile is actually negotiated and treats displayed charge percentage as proportional to rated battery energy. Real time can change with charger protocols, cable losses, temperature, active pass-through loads, battery condition, current taper and the power bank charging controller.
Compare compatible chargers against a deadline
Use bank capacity, starting/target charge, charging efficiency, bank input limit and finishing allowance above. Enter watts for an output profile you have independently confirmed is compatible. This comparison cannot discover USB protocols or cable capability. Example options are assumptions, not product recommendations.
Estimate one recharge or compare compatible charger options
The original calculator estimates a selected bank recharge using direct watts or a voltage/current profile, a bank input cap, charging efficiency and an editable near-full allowance. The additional comparison uses the same battery assumptions to compare several independently confirmed compatible profiles and a time deadline. It does not test USB compatibility.
Calculate energy before time
Use the bank’s label Wh, or mAh × the paired internal-cell voltage ÷ 1,000. Stored-energy increase = rated Wh × (target % − start %) ÷ 100. Modeled charger-side energy is that increase divided by charging efficiency as a fraction. Charging efficiency represents energy loss, not a second reduction of the battery’s rated capacity.
Effective input watts are the smallest entered applicable limit: the compatible charger profile, the bank input limit and, in the comparison, an optional cable or shared-port path limit. Unknown limits are omitted and clearly disclosed; leaving a limit blank does not verify that no limit exists. The original voltage/current mode calculates profile watts as V × A.
Anker’s label guidance distinguishes input profiles from output and combined output ratings. Enter a profile that the actual bank, charger and cable support together. Do not use the charger’s combined multi-port headline rating for one port when power is shared.
Keep the finishing allowance explicit
Base hours = modeled charger-side Wh ÷ effective W. The original finishing model applies an editable allowance proportionally across the 80%–100% region: overlap percentage points ÷ 20 × full-zone finishing minutes. This region is a software assumption, not a detected battery transition or a universal charge curve. A 20%–80% recharge gets no allowance; 80%–90% gets half the entered full-zone allowance.
Total hours = base hours + applied finishing minutes ÷ 60. If your measured average input already includes all tapering over the selected range, use an appropriate zero additional allowance to avoid double-counting. A measured peak is not an average. Neither the model nor a larger charger guarantees that the bank will accept constant power.
Compare options against a deadline
Enter the time available in hours. For positive energy, the required effective watts are charger-side Wh ÷ (available hours − applied finishing hours). If the finishing allowance alone uses all the available time, no finite power meets that model. If the bank input cap is lower than the required watts, a larger charger label cannot fix the deadline without changing another assumption.
For a 37 Wh bank charged from 0% to 100%, 90% efficiency and a 20-minute finishing allowance, an 18 W bank input limit gives about 2.617284 hours. Compatible 18 W and 65 W options both cap at 18 W and tie. A two-hour deadline would need about 24.666667 effective watts, above that bank cap. A known 10 W cable or shared-port path would slow either option further.
All fastest ties are shown. A zero-energy comparison returns zero time and ignores the finishing allowance; it does not perform a discharge. The original recharge form retains its own accepted target rules. Changing inputs clears the previous comparison.
Input and interpretation limits
Use 1–20 options, positive compatible watts and optional positive path limits up to 1,000 W. The deadline must be positive and no greater than 1,000,000 hours. Percentages are 0–100 and the finishing allowance is 0–1,440 minutes. Plain decimals up to 18 places are compared exactly; displays round to six places.
The comparison does not infer protocols, voltage support, cable electronics, temperature throttling, interruptions or pass-through loads. Treat its deadlines as conditional estimates. To allocate the charged energy among devices use Power Bank Charge Count; to plan power use over time use Power Bank Runtime. No charging session is started or recorded by this page.