A 5000mAh power bank delivers 11–13Wh usable energy, giving 1 phone charge or 2–6 hours of 2–5W use.
For quick planning, think in watt-hours (Wh), not milliamp-hours (mAh). A single-cell bank holds ~18.5Wh on paper (5,000mAh × 3.7V ÷ 1,000). Conversion and heat losses cut that to roughly 60–70% at the USB port, or ~11–13Wh. Runtime is usable Wh divided by your device’s watts.
5000mAh Power Bank Hours: Quick Estimates
Use the table below to turn that rule into practical ranges. Pick the device type or power level that matches what you plan to run or recharge. These are ballpark figures based on 11–13Wh usable energy.
| Device/Use | Typical Draw Or Battery | Estimated Outcome |
|---|---|---|
| Smartphone (4,000–5,000mAh pack) | ~15–19Wh battery | ~0.6–0.9 full charge |
| Light Phone Use While Plugged In | ~2–3W | ~4–6 hours of support |
| Heavy Phone Use Or Small Tablet | ~4–5W | ~2–3 hours of support |
| Earbuds Case | ~1.5–2Wh | ~5–8 case recharges |
| Smartwatch/Fitness Band | ~0.5–1Wh battery | ~11–20 recharges |
| USB Fan/Desk Light | ~1–2W | ~6–13 hours |
| Action Camera | ~4–6Wh battery | ~2 charges |
Why mAh Misleads And Wh Solves The Math
Milliamp-hours measure charge at the cell’s voltage. Your phone charges at 5–9–20V over USB, but the cell inside a compact bank sits near 3.6–3.7V. Energy equals voltage times amp-hours, which is why 5,000mAh at ~3.7V equals about 18.5Wh. Because the bank boosts voltage and the phone steps it back down, energy is lost in the conversion chain. Only ~11–13Wh reaches the device. That is why mAh alone can seem high while real runtime feels shorter.
How To Estimate Runtime For Your Device
Step 1: Find Or Infer Power
Check a spec sheet, a charger readout, or a USB meter. No number? Use ranges: 2–3W for light phone use, 4–5W for heavy phone use, 1–2W for small accessories, and 10W for a compact tablet.
Step 2: Convert Bank Capacity To Usable Wh
Start from 18.5Wh (5,000mAh × 3.7V ÷ 1,000). Apply ~65% as a wired baseline. That gives ~12Wh usable. Wireless adds losses; budget ~55% if you charge magnetically.
Step 3: Divide Wh By Watts
Runtime in hours equals usable Wh divided by your device’s draw. With ~12Wh, a 2W load runs ~6 hours; a 5W load runs ~2.4 hours. For “full charges,” compare usable Wh to the phone battery’s Wh. Once you try this, the math takes seconds on any device. Keep a small note handy on most phones today. Try it.
Real Examples With A 5,000mAh Bank
Light Phone Session
Browsing, texting, or streaming music with the screen dimmed lands near 2–3W. Expect 4–6 hours of added use before the bank is empty.
Heavy Phone Session
Gaming, hotspot, or long 4K clips push draw to 4–5W or more. The same ~12Wh now lasts 2–3 hours. Hot screens and high brightness trim that further.
One Full Recharge Or Not?
Many current phones hold 15–19Wh. Against ~12Wh from a compact bank, expect 60–90% of a refill. Small-battery phones may reach 100% with a little left. A mini tablet with a 25Wh pack gets a partial top-up.
What Changes The Outcome
Cable, Port, And Protocol
Short, thick USB-C cables shed less energy. Matching the fast-charge mode helps because the phone can raise voltage instead of pulling high current at 5V. With USB Power Delivery, a compact bank can step up to 9V, 12V, or more when both ends agree, which trims conversion loss and speeds the refill.
Wireless Adds Loss
Magnetic pads are handy for travel, yet they drop efficiency. A 5,000mAh bank with a Qi2 pad may deliver only ~9–10Wh to the phone. That turns a near-full refill into a half-charge and shortens “hours of use.”
Ambient Temperature
Cold packs sag; hot packs waste energy as heat throttling. Mid-room temps keep both the bank and the phone in a sweet spot.
Battery Age
Every cycle erodes capacity. After a year of regular use, both bank and phone may hold less energy than new, so the same setup gives less runtime.
Authoritative Numbers You Can Use
Three facts anchor the math. A single lithium-ion cell sits near 3.6–3.7V nominal. Energy is volts × amp-hours, so 5,000mAh near 3.7V equals about 18.5Wh. Small banks deliver only about 60–70% of that to a phone due to conversion steps. The links below explain those points.
See Battery University for the nominal cell figure and Wh examples, Anker’s support page for the 60–70% delivered energy, and the USB-IF page on USB Power Delivery for voltage and power ranges used during fast-charging.
Charge Counts For Popular Device Types
Use this second table when you care about charges, not hours. Numbers assume wired charging and ~12Wh usable. Your device may land above or below the range based on screen time, background tasks, and battery health.
| Device Type | Battery Or Draw | Likely Charges/Hours |
|---|---|---|
| Compact Phone | ~11–13Wh pack | ~80–100% once |
| Large Phone | ~15–19Wh pack | ~60–90% once |
| Mini Tablet | ~20–30Wh pack | ~30–60% once |
| Wireless Earbuds Case | ~1.5–2Wh | ~5–8 recharges |
| Smartwatch | ~0.5–1Wh | ~11–20 recharges |
| USB Fan/LED | ~1–2W draw | ~6–13 hours |
| Action Cam | ~4–6Wh pack | ~2 charges |
How Fast Will It Recharge My Phone?
Speed depends on both ends of the link. If your phone supports USB Power Delivery at 18–30W and the bank can supply that mode, refills run quicker at higher voltage with lower current. If the bank tops out at 5V/2A, speed will trail. Wireless tops are gentler and slower.
Tip: Match Chargers And Cables
Pair a bank that supports your phone’s mode with a certified USB-C cable rated for the current you need. Avoid long, thin leads for high draw. Keep the bank off soft surfaces while fast-charging so heat can move away.
Quick Checklist For Better Results
- Size your bank in Wh, then apply a 60–70% real-world factor for wired charging.
- For phones, budget 2–3W for light sessions and 4–5W for heavy sessions.
- Prefer USB-C PD when your phone supports it; higher voltage trims cable loss.
- Keep cables short and sturdy; drop wireless if you need every Wh.
- Avoid hot cars and direct sun; heat wastes energy and stresses cells.
- Older packs and older phones deliver less than new gear, so pad your estimate.
Worked Scenarios You Can Copy
Case A: Commuter And Music
Phone draw near 2W while streaming audio with the screen off. With ~12Wh usable, expect about 6 hours of extra play time. That covers a week of train rides with headroom.
Case B: Weekend Hiking
You shoot photos and short clips. Draw swings between 3–5W. The bank grants 2–4 hours of active use or a near-full refill overnight. Bring a short, sturdy cable to cut losses.
Common Clarifications
Same mAh, Different Results
Efficiency, cable loss, and the phone’s behavior create spread. Two models with the same label can deliver different usable Wh. One may hold voltage better as it nears empty. Another may run cooler and waste less energy.
Final Take: What To Expect From 5,000mAh
Plan on one phone refill if your phone’s battery is on the small side, or a healthy top-up for larger phones. Expect 2–6 hours of light-to-moderate phone use while plugged in, less for heavy tasks. For earbuds, watches, and tiny accessories, a compact bank gives many cycles. For longer tablet time or any laptop use, step up to bigger packs.
Battery University on Wh math | Anker support on 60–70% output | USB-IF on USB Power Delivery