Power Bank Real Capacity (mAh to Wh), Efficiency Loss & 100Wh Flight Limit Calculator (2026)

Convert power bank milliamp-hours (mAh) to Watt-hours (Wh), verify FAA/TSA/EASA/CAAC 100Wh & 160Wh carry-on airline compliance, and calculate real-world usable charges after 3.7V→5V/9V/20V boost converter & cable heat loss.

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Power Bank Real Capacity (mAh to Wh) & 100Wh Flight Limit Calculator — Interactive Console

Runs locally in your browser • Instant output

Quick Capacities:

Rated Capacity (mAh)

Cell Chemistry (V)

USB-PD Output (V)

Efficiency (85%)

Target Device

APPROVED FOR CABIN CARRY-ON (≤ 100 Wh)

Cleared by FAA, TSA, EASA, and DGCA without airline notification (up to 20 spare units in carry-on baggage; strictly forbidden in checked luggage).

TSA / FAA Energy Rating

74.0 Wh

Real Output @ 5V

12,580 mAh

Net Usable Energy

62.9 Wh

Full Device Charges

3.27×

Ready

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2026 Power Bank mAh to Watt-Hours (Wh) Airline Cabin Limit Table

2026 Verified Reference

Quick Answer & 2026 Technical Summary (mah to wh power bank calculator flight limit)Updated 2026 Standard

Airlines (TSA, FAA, EASA, DGCA) regulate lithium-ion power banks by Watt-hours (Wh), not mAh. Multiply `(mAh × 3.7V) ÷ 1000` to get Wh: power banks up to 100Wh (27,027 mAh at 3.7V) are allowed in carry-on luggage without approval, 100–160Wh require airline approval, and over 160Wh are strictly banned.

Wh = (mAh × Nominal_Voltage_3.7V) / 1000 | Real Output mAh = (Wh × 0.85) / Output_Voltage_5V × 1000

Carry-On Unrestricted: ≤ 100 Wh (≤ 27,027 mAh @ 3.7V)

Airline Permit Tier: 100.1 – 160 Wh (Max 2 units)

Checked Baggage: 0 Wh (Strictly Prohibited in Hold)

Rated Capacity (@ 3.7V Cell)	Energy Rating (Wh)	Usable 5V Output (~85% Eff.)	TSA / FAA / EASA / DGCA Status
10,000 mAh (Slim Pocket Pack)	`37.0 Wh`	~6,290 mAh (~1.3 Phone Charges)	Allowed in Carry-On (No Approval Needed)
20,000 mAh (Travel Standard)	`74.0 Wh`	~12,580 mAh (~2.6 Phone Charges)	Allowed in Carry-On (No Approval Needed)
27,000 mAh (Laptop USB-C PD)	`99.9 Wh`	~16,980 mAh (1 MacBook Air + 1 Phone)	Max Legal Carry-On Limit Without Permit
30,000 mAh (High-Capacity Brick)	`111.0 Wh`	~18,870 mAh (~3.9 Phone Charges)	Requires Airline Check-In Counter Approval
40,000 mAh (Expedition Bank)	`148.0 Wh`	~25,160 mAh (~5.2 Phone Charges)	Airline Approval Required (Max 2 Per Passenger)
50,000 mAh+ (Portable Station)	`185.0 Wh+`	~31,450 mAh+	Prohibited on Passenger Flights (> 160 Wh)

In-Depth ZerosUniverse Tutorial

10 Best Portable Power Bank Chargers in 2026

Read our complete step-by-step editorial guide, architecture breakdown, and defensive best practices on ZerosUniverse.

Read Full Guide

How to Use Power Bank Real Capacity (mAh to Wh) & 100Wh Flight Limit Calculator

Enter Advertised Power Bank Capacity (mAh) & Cell Chemistry Voltage

Input the marketed mAh (e.g., 10,000, 20,000, 24,000, or 27,650 mAh) and select the internal cell nominal voltage (standard 3.7V Li-Ion/Li-Po, 3.85V High-Voltage Li-Po, or 3.2V LiFePO4).

Check Your Airline Flight Compliance Verdict (Wh)

Inspect the calculated Watt-hours (Wh) against ICAO/IATA/FAA/TSA/EASA/CAAC rules (≤100Wh Carry-On Allowed, 100–160Wh Airline Approval Required, >160Wh Prohibited).

Select USB-PD Output Voltage & Target Device Battery

Pick a target device preset (or enter custom target battery mAh/Wh) and charging protocol (5V Standard, 9V/12V Fast Charge, or 20V Laptop USB-PD) to see real usable charges.

Review the Energy Loss Breakdown Waterfall

Examine how many Watt-hours are preserved vs. lost to DC-DC boost conversion (~8%–12%), cable resistance (~2%), and target device battery charging PMIC (~5%–8%).

Key Capabilities & Technical Architecture

Cell Energy (mAh ↔ Wh) & FAA/TSA/EASA/CAAC Airline Compliance Checker

Compute nominal Watt-hours ($\text{Wh} = \text{mAh} \times V_{\text{cell}} / 1000$) at 3.6V, 3.7V, or 3.85V Li-Ion/LiFePO4 voltages and instantly verify against the ≤100Wh (Allowed), 100–160Wh (Airline Approval), and >160Wh (Banned) aviation tiers.

Real-World Usable Output Capacity (5V / 9V / 15V / 20V USB-PD) Model

Reveal why a marketed '20,000 mAh' (at 3.7V cell voltage) power bank only delivers ~12,600 mAh at 5V USB output after accounting for voltage step-up ($3.7\text{V} \to 5\text{V}$) and DC-DC boost + PMIC heat loss.

Full Device Recharge Counter (Smartphones, Tablets, Handhelds & Laptops)

Calculate exact number of 0%–100% recharges for iPhone 16/17 Pro Max, Samsung Galaxy S25/S26 Ultra, Steam Deck OLED, iPad Pro, or MacBook Air M3/M4.

USB-C PD Recharge Time & Multi-Stage CC/CV Curve Estimator

Estimate how long it takes to recharge the power bank itself at 18W, 30W, 65W, 100W, or 140W USB-PD input including the final 80%–100% Constant-Voltage (CV) taper phase.

Practical Use Cases

Airport Security (TSA / EASA / DGCA / CAAC) Carry-On Verification

Confirm before flying that your 20,000 mAh (74 Wh) or 27,000 mAh (99.9 Wh) laptop power bank is legally below the strict 100 Wh (27,027 mAh @ 3.7V) carry-on ceiling.

Auditing Fake or Inflated Power Bank Capacity Claims

Compare the printed 'Rated Capacity (5V=3A)' fine print on a power bank shell against its advertised cell mAh to verify whether its boost converter efficiency meets industry standards (82%–88%).

Backpacking & Off-Grid Tech Kit Sizing

Plan the exact mAh/Wh battery bank needed to keep a phone, action camera, and laptop powered across a 3-day trip without carrying excess weight.

Frequently Asked Questions (FAQs)

Why does my 20,000 mAh power bank only charge my 5,000 mAh phone about 2.5 times instead of 4 times?+

Manufacturers advertise capacity based on the internal lithium cells' nominal voltage of **3.7V** ($20,000\text{ mAh} \times 3.7\text{V} = 74\text{ Wh}$). However, USB ports output at **5V** (or 9V/15V/20V for USB-PD). Stepping 3.7V up to 5V immediately changes the theoretical capacity to $74\text{ Wh} / 5\text{V} = 14,800\text{ mAh}$. After ~10% DC-DC boost converter loss in the power bank and ~8% charging circuit heat loss inside the phone, roughly **62–65 Wh (12,500–13,000 mAh)** of net energy reaches the phone battery—giving $\approx 2.5$ full charges.

What is the exact maximum mAh power bank allowed on airplanes without airline approval?+

Global aviation regulators (FAA, TSA, EASA, IATA, DGCA, CAAC) regulate lithium batteries by **Watt-hours (Wh)**, not mAh, setting the unrestricted carry-on limit at **100 Wh**. At a standard 3.7V cell voltage, $100\text{ Wh} = (100 \times 1000) / 3.7 = \mathbf{27,027\text{ mAh}}$. This is why flagship laptop power banks are specifically engineered to 26,800 mAh (99.16 Wh) or 27,000 mAh (99.9 Wh). Remember: power banks are strictly forbidden in checked luggage and must always go in your cabin carry-on.

What is the difference between 'Cell Capacity' and 'Rated Capacity' printed on a power bank?+

Regulatory standards (especially China's GB/T 35590 and CCC certification) require manufacturers to print two numbers on the casing: **Cell Capacity** (e.g., `20,000 mAh / 74 Wh at 3.7V`) and **Rated Capacity** (e.g., `12,600 mAh at 5V=3A`). Rated Capacity is the true measured energy delivered out of the USB port at 5V.

Does fast charging at 9V or 20V USB-PD waste more power bank battery than slow 5V charging?+

Running the power bank's synchronous boost converter at high wattage (e.g., 65W–140W at 20V) generates slightly more inductor and MOSFET switching heat (reducing conversion efficiency by ~3%–5% compared to gentle 5V/1A trickle charging), though high voltage reduces $I^2R$ copper loss across the USB-C cable.

Why can't I bring a power bank onto a flight if the Wh label has rubbed off?+

Aviation security officers (especially at CAAC airports in China and European/Asian hubs) are instructed to confiscate any lithium power bank that lacks a clearly legible manufacturer print showing either Watt-hours (Wh) or both Voltage (V) and Milliamp-hours (mAh) so they can verify it is under 100 Wh.