A 5,000mAh power bank delivers about 11–13Wh to devices—roughly one small-phone charge or a few hours for low-power gear.
Shoppers ask this all the time, and the honest answer hinges on energy, not just milliamp-hours. A compact pack holds cells near 3.7V. When that energy is boosted to USB output and travels through cables, some of it turns into heat. That’s why a label rarely matches the runtime you see in daily use.
Quick Math: Usable Energy From A 5,000mAh Pack
Manufacturers rate capacity at cell voltage. You can convert capacity into watt-hours with a simple mAh-to-Wh formula: Wh = (mAh × V) ÷ 1000. With a 3.7V cell, 5,000mAh equals about 18.5Wh on the cell side. Real packs give 60–70% of that to your device after conversion, so plan on roughly 11–13Wh delivered. That efficiency range matches guidance from major brands; see Anker’s note that packs typically deliver about 60–70% of rated capacity due to conversion and cable losses (efficiency explanation).
| Spec Or Factor | Typical Value | What It Means |
|---|---|---|
| Cell Voltage | 3.6–3.7V nominal | mAh is rated at cell level, not USB output. |
| Cell Energy (Wh) | ~18.5Wh | 5,000mAh × 3.7V ÷ 1000. |
| Delivery Efficiency | ~60–70% | Losses from boosting to 5V/9V/12V and cable resistance. |
| Usable Energy To Device | ~11–13Wh | What your phone, earbuds, or camera actually receive. |
| Output Power | 5W–20W | Higher wattage drains the pack faster. |
How Many Charges Can You Expect?
The clean way to estimate is to compare usable energy from the pack with the device battery’s watt-hours. Many phones sit between 11–20Wh; earbuds and headlamps use far less. Use the ranges below as a planning guide.
Phone-Size Battery Examples
Small phones with ~3,000mAh batteries (near 11–12Wh at 3.85V) can reach close to one full charge. Midrange phones around 4,000mAh (15–16Wh) land near two-thirds to three-quarters of a charge. Big 5,000–6,000mAh handsets can only sip back about half a charge from a tiny pack.
Other Gadgets
Earbuds cases, fitness trackers, action cams, and bike lights usually hold 0.5–5Wh. A 5,000mAh pack can refill those several times. Laptops are out of scope for this size unless you only need an emergency top-off on low-power tablets with modest batteries.
Estimated 5000mAh Power Bank Runtime With Common Loads
Another way to think about runtime is by steady power draw. Use the table below with the usable energy range. Pick a draw that matches your device’s charging rate or direct-power usage.
(Skip to the runtime table near the end for a handy load-vs-hours cheat sheet.)
What Shrinks Or Stretches Your Runtime
Conversion Losses
The pack’s boost circuit raises cell voltage to USB levels. That step burns energy. Cables and connectors drop a little more. Phones then step the voltage back down to charge their own 3.8V class cells. Each stage trims the total. Quality electronics and short, thick cables reduce waste.
Charging Speed
Fast charging is handy, but higher wattage means the stored energy empties sooner. Energy is the bucket; power is how fast you pour it. A small pack doing 20W will finish well before the same pack at 5W, even though both start with the same Wh.
Battery Size In The Device
Modern phones span a wide range of capacities. Compact models can sit near 3,000mAh, while heavy-duty phones often reach 5,000–6,000mAh or more. If your handset is on the larger end, use this pocket pack for a partial refill between outlets.
Temperature
Cold cuts capacity. Lithium-ion delivers less in freezing conditions and rebounds when warmed. If you’re outdoors in winter, stash the pack in an inside pocket and keep the cable short.
Age And Health
Cells fade with cycles and time. A pack that’s two years old won’t match day-one stamina. The same is true for the device you’re charging; aged phone batteries accept less energy and waste more as heat.
Step-By-Step: Estimate Your Own Runtime
- Find the power bank’s rated voltage. Most small packs use 3.7V cells.
- Convert to watt-hours: Wh = (5000 × 3.7) ÷ 1000 ≈ 18.5Wh.
- Apply delivery efficiency: multiply by 0.6–0.7. Usable ≈ 11–13Wh.
- Check your device battery in Wh. If only mAh is given, multiply by 3.85V and divide by 1000.
- Divide device Wh by usable Wh to estimate the percent charge you can add. Or divide usable Wh by your charging wattage to estimate hours of output.
Realistic Use Cases For A 5,000mAh Pack
Day Trips And Commutes
Perfect for topping up a phone once during a long day, especially if you start above 30%. It keeps maps, rideshare, and messaging alive without carrying a brick.
Weekend Backup For Small Gear
Great for earbuds, headlamps, bike lights, and action cams. Those tiny batteries refill many times, so one pocket pack can serve several items.
Emergency Boost
Handy during outages to power a phone for calls or texts, run a compact hotspot for a while, or feed a GPS tracker. Keep expectations modest for tablets and game consoles; the energy budget is thin for those.
Ways To Stretch Each Charge
Use A Short, Low-Loss Cable
Thicker conductors drop fewer volts. USB-C cables rated for 3A tend to perform better for small packs. Avoid frayed or mystery cables.
Match The Speed To Your Need
If you don’t need a sprint, charge at 5–10W. Slower rates curb heat and reduce waste through the conversion path.
Charge In Warmer Rooms
Avoid charging or discharging while the pack is icy. Keep it near room temperature for better capacity.
Top Up Early
Partial refills are battery-friendly. Instead of draining everything to zero, add a chunk when you drop near 20–40%.
When A Larger Bank Makes Sense
If you carry a phone with a 5,000mAh battery, a 10,000–20,000mAh bank aligns better with your needs. Bigger packs store closer to 37–74Wh at the cell side and deliver more after losses, which means multiple phone refills or one tablet boost with room to spare. For ultralight days, the 5,000mAh size still shines as a safety net.
Specs To Check Before You Buy
Watt-Hours On The Label
Some brands print Wh directly. That number sidesteps the cell-voltage confusion and makes comparisons easy.
Efficiency Claims
Look for transparent figures for real-world output. Numbers near 60–70% line up with how small packs behave. If a spec sheet promises near-lossless delivery, treat it as marketing puff.
Output Ports And Speeds
One USB-C port that can do both input and output keeps things simple. If you need to charge a phone and earbuds together, pick a model with a second port.
Safety And Protections
Reputable makers add protection against over-current, short circuit, and over-temperature. That protects your phone and the pack during heavy use.
Example Calculations You Can Copy
Small Phone, 3,000mAh At 3.85V
Battery ≈ 11.6Wh. Pack usable ≈ 11–13Wh. Expect close to one full charge, depending on cable, screen-on time while charging, and temperature.
Mid Phone, 4,500mAh At 3.85V
Battery ≈ 17.3Wh. Pack usable ≈ 11–13Wh. Expect roughly 60–75% refill.
Big Phone, 6,000mAh At 3.85V
Battery ≈ 23.1Wh. Pack usable ≈ 11–13Wh. Expect a partial refill in the 40–55% range.
Estimated 5000mAh Power Bank Runtime — Load Vs. Hours
Here’s the promised cheat sheet from earlier. Match the load to your device or charging rate, then read the hours you can expect from a small pack with 11–13Wh usable energy.
| Approx. Load | Usable Energy (11–13Wh) | Estimated Runtime |
|---|---|---|
| 5W USB (5V/1A) | 11–13Wh | ~2.2–2.6 hours of output |
| 10W USB (5V/2A) | 11–13Wh | ~1.1–1.3 hours |
| 15W USB-C PD | 11–13Wh | ~45–50 minutes |
| 2W Headlamp | 11–13Wh | ~5.5–6.5 hours |
| 1W GPS/Tracker | 11–13Wh | ~11–13 hours |
Bottom Line: What To Expect Day To Day
A compact 5,000mAh bank is a light, pocketable safety net. With about 11–13Wh delivered to devices, you’ll get one near-full refill for a small handset, a solid top-off for larger phones, and many refills for tiny gear. If you often run two devices or crave full phone cycles, step up in size; otherwise, this pocket pack is a trusty everyday backup.