A 5,000mAh power bank typically delivers about one full phone charge, with 60–75% of its energy usable.
Why This Question Matters
You grab a slim charger for travel or daily backup and need to know if it can take your phone from low to full once, twice, or more. The answer comes from simple math and a few real-world quirks: conversion losses, cable quality, the size of your phone’s battery, wireless vs. wired, and how you use the phone while it’s charging.
Quick Takeaways
- A 5,000mAh pack holds about 18.5Wh (based on a single 3.6–3.7V lithium-ion cell).
- Usable energy is lower than the label because of voltage boost and heat loss.
- Count on ~60–75% of the rated energy reaching the phone.
- Small phones (≈3,000mAh) often see 1.2–1.5 full refills; large phones (≈5,000mAh) land closer to 0.7–0.9.
Typical Full Recharges From A 5,000mAh Pack
Use this broad view to set expectations. The numbers assume realistic losses and a wired connection.
| Device Battery (mAh) | Charges @65% | Charges @75% |
|---|---|---|
| 3,000 | ~1.1 | ~1.3 |
| 4,000 | ~0.8 | ~0.9 |
| 4,500 | ~0.7 | ~0.8 |
| 5,000 | ~0.6 | ~0.7 |
| Earbuds Case (500) | ~6.0 | ~7.0 |
| Smartwatch (300) | ~10.0 | ~12.0 |
How Many Recharges From A 5,000mAh Bank? Real-World Method
Here’s the clean three-step way to estimate without spreadsheets.
Step 1: Convert mAh To Wh
Power banks use a single lithium-ion cell with a nominal voltage near 3.6–3.7V. Multiply capacity (Ah) by the cell voltage to get watt-hours (Wh). A 5,000mAh unit is 5Ah × 3.7V ≈ 18.5Wh. On nominal voltage: see the explanation of lithium-ion nominal cell voltage.
Step 2: Apply Efficiency
Energy leaves the cell at ~3.7V, then the electronics boost it to 5V (or 9V/12V for fast modes). That conversion and heat trim output. Real end-to-end results land near 60–75%. Usable energy: 18.5Wh × 0.65–0.75 ≈ 12.0–13.9Wh.
Step 3: Divide By Your Phone’s Battery Energy
Phone batteries sit roughly between 10–19Wh (about 3,000–5,000mAh at ~3.85–3.9V on the device side). A 4,000mAh phone is ~15Wh, so this small bank gives ~12.0–13.9Wh ÷ 15Wh ≈ 0.8–0.9 full refills.
Why The Label Doesn’t Match What You Get
The printed mAh lives at the internal cell voltage, not at the USB output. Boosting voltage takes energy, and cables plus device charging circuits shed a bit more. High-voltage fast modes trade speed for small extra losses. That’s why a 5,000mAh unit rarely delivers 5,000mAh at 5V.
About Your Phone’s Battery Size
Recent phones commonly range from ~3,000–5,000mAh. Compact or older models sit closer to 3,000–3,500mAh, while big-battery phones push 4,500–5,000mAh. Larger packs need more energy for a full refill, so a tiny bank stretches farther with small phones or with accessories like earbuds and watches.
Does Fast Charging Change The Count?
Speed doesn’t create energy. A 20W port can refill a phone sooner, but the total number of refills still follows total watt-hours. Some packs run slightly less efficiently at higher voltage steps; the 60–75% band already covers that. For context on USB-C power profiles and PD, see the USB-IF page on USB Power Delivery.
Cable And Port Choices Matter
A short, well-made USB-C cable wastes less energy than a long, thin one. Matching the right port helps too. Many mini banks offer one USB-C that handles both input and output plus a USB-A for legacy leads. If your phone supports Power Delivery, use the USB-C port to keep voltage and current inside agreed limits at modest power levels.
What About Wireless Charging?
Wireless adds conversion on both sides, so expect fewer refills. On compact banks with a Qi pad, your real-world number can drop by another 10–20% compared with a cable. With only 5,000mAh on tap, that can be the difference between scraping a full refill and landing short.
Plan Around Aging
Rechargeable cells fade with cycles and heat. A pocket bank that’s been through many top-ups may hold less than when it was new. Your phone ages too. Apple explains that capacity retention drops over cycles, with later models rated for more cycles under ideal conditions; see iPhone battery and performance for context. As capacity shifts on either side, “one full refill” moves up or down across months of use.
Mini Math For Your Exact Phone
You can get very close with three numbers:
- Bank energy at 3.7V: 18.5Wh for a 5,000mAh unit.
- Estimated efficiency: pick 0.65 for basic gear, 0.75 for quality models.
- Your phone’s energy: phone mAh × 3.85V ÷ 1000.
Now calculate: usable bank Wh ÷ phone Wh.
Worked Samples
- Small phone (3,200mAh): phone energy ≈ 12.3Wh. Usable bank ≈ 12.0–13.9Wh. Full refills ≈ 1.0–1.1.
- Mid phone (4,000mAh): phone energy ≈ 15.4Wh. Full refills ≈ 0.8–0.9.
- Large phone (5,000mAh): phone energy ≈ 19.3Wh. Full refills ≈ 0.6–0.7.
- Earbuds case (500mAh): phone energy ≈ 1.9Wh. Full refills ≈ 6–7.
Why mAh To Wh Matters
mAh compares capacity at the same voltage. Wh compares total energy across different voltages, so it’s the fair way to size a bank for a device. That’s also how airline rules are written: limits are set by Watt-hours, not mAh. See the FAA chart on lithium battery rules for carry-on guidance; a 5,000mAh pack at 3.7V is ~18.5Wh, well under common limits.
Picking A 5,000mAh Pocket Pack: How Many Recharges To Expect
Light users with compact phones often get a full refill and change. Heavy users with big screens may land shy of a full refill. Games, streaming, hot weather, and 5G drain while charging. Airplane mode or charging while the phone is idle can stretch the number.
When A Tiny Bank Makes Sense
Commuting, dinner runs, day trips, or airport hops—this is where a small bank shines. It slips into a pocket, weighs little, and tops up a phone from the red zone to safe territory. Keep a short USB-C cable in the same pouch to avoid wasting energy through a worn or overly long lead.
When You’ll Want More Than 5,000mAh
If your phone sits near 4,500–5,000mAh and you run maps or media for hours, step up to 10,000–12,000mAh. The same math applies: double the capacity, similar efficiency, about double the refills. Laptops and tablets are a different game—think in watt-hours and required output power, not just mAh, and pick gear built for those loads.
Factors That Change Your Number Of Recharges
| Factor | What It Does | Tip |
|---|---|---|
| Phone Battery Size | Bigger batteries need more energy for one full refill. | Check your exact model’s mAh. |
| Charging Speed | Higher voltage modes add small conversion losses. | Use moderate PD levels when possible. |
| Cable Quality | Thin, long, or worn cables waste power as heat. | Pick a short USB-C cable. |
| Wireless Charging | Extra conversion drops usable energy. | Prefer wired for a tiny bank. |
| Use While Charging | Screen-on and 5G eat into the refill. | Let the phone rest while charging. |
| Temperature | Heat trims efficiency and speeds wear. | Charge in the shade. |
How To Spot A Realistic Spec Sheet
Look for both mAh and Wh on the label. Clear specs list rated output at 5V and, in better cases, show measured usable energy. Claims that a tiny pack can refill a large modern phone two or three times should raise an eyebrow. Independent tests that publish usable Wh under load give the clearest picture.
Travel And Safety Notes
Carry spare batteries in your hand luggage and protect ports from short-circuit. A 5,000mAh unit sits near 18.5Wh, which fits well under common 100Wh carry-on caps. If a pack swells, smells odd, or runs hot while idle, retire it. For airline allowances by Wh and spare limits, the FAA’s PackSafe page linked above is the reference many travelers use. IATA’s guidance also frames limits in Watt-hours and classifies these packs as spare batteries for carry-on only; see its passenger guidance.
Simple Buying Checklist
- Capacity fit: do you need one phone refill or more?
- Ports: USB-C with PD for most modern phones; legacy USB-A if needed.
- Size and weight: pocketable for daily carry.
- Clear specs: mAh and Wh listed, honest output ratings.
- Included cable: a short, durable USB-C lead saves energy in practice.
Bottom Line
A compact 5,000mAh bank is a handy safety net. With phone sizes spanning a wide range and efficiency factors in play, expect around one full refill for small and mid phones, and closer to two-thirds for big batteries. Do the quick Wh math for your model and you’ll know what to expect every time.