Convert WattHours to AmpHours and AmpHours to WattHours
Watthours (Wh) and Amphours (Ah) are two very common units in electrical engineering  simplified, Watthours is the unit of energy, while Amphours is the unit of battery capacity.
Direct conversion from Watthours to Amphours and from Amphours to Watthours is not possible without introducing the third unit  nominal and/or actual voltage of the electricity source, mostly battery.
On This Page:
 How to Convert WattHours to AmpHours and AmpHours to WattHours
 WattHours to AmpHours and AmpHours to WattHours Conversion Examples
 WattHours to AmpHours and AmpHours to WattHours Conversion Calculators
 WattHours to AmpHours and AmpHours to WattHours Charts
How to Convert WattHours to AmpHours and AmpHours to WattHours
Before diving into math and physics, it is important to know which unit is used for what:
 'I': current strength, given in Amps (A),
 'P': power, given in Watts (W),
 'U': potential difference, given in Volts (V),
 'E': energy, given in Joules (J) and sometimes in Wh (WattHours)  1 Wh equals 3600 J,
 'C': battery capacity, given in AmpHours (Ah),
 'T': time, measured in seconds (s) and sometimes in hours (h).
Also, battery capacity is often defined as the ability of the battery to provide a certain current for a certain period of time  for leadacid batteries, the standard discharge time is 20h, but for other batteries, various discharging conditions may be used.
In order to convert Watthours to Amphours and Amphours to Watthours one must use the following formulas:
E(Wh) = I(A) * T(h) * U(V)
E(Wh) = C(Ah) * U(V)
WattHours to AmpHours and AmpHours to WattHours Conversion Examples
Here are several WattHours to AmpHours and AmpHours to WattHours conversion examples:
Example 1: The battery features capacity of 100Ah and a constant output voltage of 24V. How many Watthours of energy is the battery able to provide?
In order to calculate this, we use the following formula:
E(Wh) = C(Ah) * U(V) = 100Ah * 24V = 2400 Wh
Example 2: If the sump pump backup battery must provide 1800Wh without recharging, what is its minimum required capacity if the nominal battery voltage is 12 volts?
In order to calculate battery's required capacity, we use the following formula:
C(Ah) = E(Wh) / U(V) = 1800Wh / 12V = 150 Ah
Example 3: If the power bank features an internal 3.7V 20000 mAh battery, how many Watthours is it able to provide at 5V?
This is a trick question  in order to calculate watthours of the battery, we use the following formula:
E(Wh) = C(Ah) * U/V) = 20Ah * 3.7V = 74Wh
The output voltage of 5V in this example is of absolutely no importance.
In reallife we use the same formulas to calculate WattHours to AmpHours and AmpHours to WattHours, but in order to get as accurate results as possible, one should use constant current and constant power discharge charts of the batteries being used  more on that later.
WattHours to AmpHours and AmpHours to WattHours Conversion Calculators
In order to convert WattHours to AmpHours and AmpHours to WattHours, feel free to use these conversion calculators  write the values that You have and click 'Calculate' to convert them.
WattHours to AmpHours 
AmpHours to WattHours 

WattHours: Volts: AmpHours: 
AmpHours: Volts: WattHours: 
WattHours to AmpHours Chart
The following WattHours to AmpHours chart lists the required capacity (given in Amphours) of specific energy sources, depending on their nominal voltage:
Energy (Wh) 
Required Capacity (Ah) @ Nominal Voltage  
12 Volts  24 Volts  36 Volts  120 Volts  230 Volts  
250 Wh  20.83 Ah  10.41 Ah  6.94 Ah  2.083 Ah  1.087 Ah 
500 Wh  41.67 Ah  20.83 Ah  13.89 Ah  4.167 Ah  2.174 Ah 
746 Wh  62.16 Ah  31.08 Ah  20.72 Ah  6.216 Ah  3.243 Ah 
1000 Wh  83.33 Ah  41.66 Ah  27.78 Ah  8.333 Ah  4.238 Ah 
1492 Wh  124.3 Ah  62.16 Ah  41.44 Ah  12.43 Ah  6.487 Ah 
2000 Wh  166.6 Ah  83.3 Ah  55.5 Ah  16.66 Ah  8.695 Ah 
2238 Wh  186.5 Ah  93.25 Ah  62.16 Ah  18.65 Ah  9.730 Ah 
2984 Wh  248.6 Ah  124.3 Ah  82.88 Ah  24.86 Ah  12.97 Ah 
3730 Wh  310.8 Ah  155.4 Ah  103.6 Ah  31.08 Ah  16.21 Ah 
5000 Wh (5 kWh)  416.6 Ah  208.3 Ah  138.8 Ah  41.6 Ah  21.74 Ah 
10 kWh  833.3 Ah  416.6 Ah  277.8 Ah  83.3 Ah  43.48 Ah 
For example: If Your 36V system needs at least 2000Wh of energy, what is the minimum required capacity of the battery pack?
C(Ah) = E(Wh) / U(V) = 2000Wh / 36V = 55.5 Ah
Note that some electric cars feature batteries being able to store 80100 or even more kWh (80000100000 Wh) of energy.
AmpHours to WattHours Chart
The following AmpHours to WattHours chart lists the energy values (given in Watthours), depending on the specific capacity (given in Ah) and nominal voltage (given in V):
Capacity (AmpHours)  Energy (Wh) @ Nominal Voltage  
12 Volts  24 Volts  36 Volts  120 Volts  230 Volts  
1 Ah  12 Wh  24 Wh  36 Wh  120 Wh  230 Wh 
2 Ah  24 Wh  48 Wh  72 Wh  240 Wh  460 Wh 
5 Ah  60 Wh  120 Wh  180 Wh  600 Wh  1150 Wh 
10 Ah  120 Wh  240 Wh  360 Wh  1200 Wh  2300 Wh 
25 Ah  300 Wh  600 Wh  900 Wh  3000 Wh  5750 Wh 
50 Ah  600 Wh  1200 Wh  1800 Wh  6000 Wh  11500 Wh 
100 Ah  1.2 kWh  2.4 kWh  3.6 kWh  12 kWh  23 kWh 
200 Ah  2.4 kWh  4.8 kWh  7.2 kWh  24 kWh  46 kWh 
500 Ah  6 kWh  12 kWh  18 kWh  60 kWh  115 kWh 
1000 Ah  12 kWh  24 kWh  36 kWh  120 kWh  230 kWh 
For example: If You have 10 (ten) 12V 100Ah batteries connected in series, how much energy that batterypack would be able to store?
E(Wh) = C(Ah) * U(V) = 100Ah * 10 * 12V = 12000 Wh = 12 kWh
Long Story Short: When calculating watthours (energy), one must know Amps (current), hours (time), and Volts (voltage), or capacity (Ah) and Volts (voltage)  when converting Wh (again, the energy given in watthours) to Ah (again, capacity given in Amphours) and back, one must know the nominal voltage of the system.
If the power source of the electric system is a leadacid battery, and the discharge time is relatively short, the effective capacity of the battery decreases, requiring the users to check the constant current and constant power discharge tables of the batteries in question.