Power Bank & Battery Converter

mAh to Wh Converter

Power bank airline travel compliance, drone battery rating, smartphone battery comparisons. Converts battery milliamp-hours and cell nominal voltage (3.7V Li-ion, 1.2V NiMH, 3.2V LiFePO4) into Watt-hours.

mAh to Wh Converter
mAh
Volts
Calculated Result
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Instant Calculation
Auxiliary Value
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Engineering Output
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Step-by-Step Derivation ▼ Show Steps
Governing Formula Verified Physics
Watt-Hours (Wh) = [Capacity (mAh) × Voltage (V)] / 1000

Calculations adhere to standard electrical equations and National Electrical Code guidelines.

Engineering Principles & Calculations

This calculator uses the exact mathematical relationships between Capacity (mAh), Nominal Voltage (V - with presets for 3.7V, 7.4V, 11.1V, 12V) to determine Energy (Wh), Flight Airline Limit Check (≤100Wh TSA Safe). In practical applications, electrical systems must account for safety derating factors, nominal vs actual voltages, and conductor resistance losses.

Converts battery milliamp-hours and cell nominal voltage (3.7V Li-ion, 1.2V NiMH, 3.2V LiFePO4) into Watt-hours.

Typical Application & Best Practices

Power bank airline travel compliance, drone battery rating, smartphone battery comparisons.

Reference Matrix

mAh to Wh Converter Benchmark Lookup Table

Power Bank RatingInternal VoltageEnergy Capacity (Wh)TSA Flight Limit Status
5,000 mAh3.7 V (1-Cell Li-ion)18.5 WhApproved (Carry-on)
10,000 mAh3.7 V (1-Cell Li-ion)37.0 WhApproved (Carry-on)
20,000 mAh3.7 V (1-Cell Li-ion)74.0 WhApproved (Carry-on)
26,800 mAh3.7 V (1-Cell Li-ion)99.16 WhMax Legal Carry-On (Under 100Wh)
30,000 mAh3.7 V (1-Cell Li-ion)111.0 WhRequires Airline Approval (100-160Wh)
50,000 mAh3.7 V (1-Cell Li-ion)185.0 WhProhibited on Passenger Flights
FAQ

Frequently Asked Questions

How do you convert mAh to Wh? +
Multiply mAh by battery voltage and divide by 1000: Wh = (mAh × V) / 1000. For a 20,000mAh 3.7V power bank: (20,000 × 3.7) / 1000 = 74 Wh.
What is the TSA flight limit for battery capacity in Wh? +
TSA limits passengers to power banks of 100 Watt-hours (Wh) or less in carry-on baggage. Batteries between 101-160 Wh require airline approval, and >160 Wh are prohibited.
Why do power banks use 3.7V instead of 5V? +
Power banks contain lithium-ion cells with a nominal voltage of 3.7V. When charging a 5V USB phone, internal circuitry steps voltage up to 5V, reducing effective output mAh by about 30%.

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