Watts to kWh & kWh to Watts Converter
A free watts to kwh calculator for solar installers, B2B buyers and facility managers. Convert watts to kwh and kwh to watts in seconds — enter any two values (power, time or energy) and the third is calculated instantly, with lookup tables, formulas and a LiFePO4 battery-sizing guide.
Watts to kWh Calculator
This free watts to kwh calculator converts watts to kwh and kwh to watts in real time. Use it to convert watts to kwh for a given runtime, or flip to the kwh to watts calculator to find the power draw a battery can support. Enter any two values — power in watts, time in hours or energy in kilowatt-hours — and the third updates instantly.
1 · Enter Any Two Values
Formula: kWh = W × h ÷ 1,000 · W = kWh × 1,000 ÷ h · h = kWh × 1,000 ÷ W. Leave the value you want calculated empty.
2 · Results
A kilowatt-hour (kWh) measures energy — the total amount stored or consumed. Watts (W) measure power — the rate of use at any instant. You always need time to convert between the two.
dawnice “48V” LiFePO4 batteries use a 51.2V nominal voltage (16-cell architecture), which is why a 100Ah pack stores 5.12kWh — not 4.8kWh. Use 51.2V in the calculator for accurate runtime figures.
Watts, kWh & kW Lookup Tables
Pre-calculated conversions for the most common power and energy figures. Use these tables to size batteries, inverters and solar systems at a glance.
| Power (Watts) | kWh at 1h | kWh at 4h | kWh at 8h | kWh at 24h |
|---|---|---|---|---|
| 100W | 0.1 | 0.4 | 0.8 | 2.4 |
| 300W | 0.3 | 1.2 | 2.4 | 7.2 |
| 500W | 0.5 | 2 | 4 | 12 |
| 1,000W | 1 | 4 | 8 | 24 |
| 1,500W | 1.5 | 6 | 12 | 36 |
| 2,000W | 2 | 8 | 16 | 48 |
| 3,000W | 3 | 12 | 24 | 72 |
| 5,000W | 5 | 20 | 40 | 120 |
| Energy (kWh) | Watts at 1h | Watts at 4h | Watts at 8h | Watts at 24h |
|---|---|---|---|---|
| 1 kWh | 1,000 | 250 | 125 | 41.67 |
| 5 kWh | 5,000 | 1,250 | 625 | 208.33 |
| 10 kWh | 10,000 | 2,500 | 1,250 | 416.67 |
| 20 kWh | 20,000 | 5,000 | 2,500 | 833.33 |
| 50 kWh | 50,000 | 12,500 | 6,250 | 2,083.33 |
| 100 kWh | 100,000 | 25,000 | 12,500 | 4,166.67 |
| 200 kWh | 200,000 | 50,000 | 25,000 | 8,333.33 |
| kW | Watts |
|---|---|
| 0.5 kW | 500 |
| 1 kW | 1,000 |
| 1.5 kW | 1,500 |
| 2 kW | 2,000 |
| 3 kW | 3,000 |
| 5 kW | 5,000 |
| 10 kW | 10,000 |
| 50 kW | 50,000 |
| 100 kW | 100,000 |
| 200 kW | 200,000 |
How to Convert Watts to kWh
Converting watts to kWh is simple once you know the runtime. The formula is kWh = watts × hours ÷ 1,000. To calculate kwh from watts, multiply the power draw by the number of hours the load runs, then divide by 1,000 to convert watt hours to kwh.
For example, a 1,500W appliance running for 4 hours consumes 1,500 × 4 ÷ 1,000 = 6 kWh. Run it for 8 hours and the same appliance uses 12 kWh.
For a smaller load, a 500W refrigerator and LED lighting running for 8 hours uses 500 × 8 ÷ 1,000 = 4 kWh per day — a realistic backup budget for a Nigerian home or shop during grid outages.
Every watt to kwh conversion starts with the same two numbers: the load’s wattage and how long it runs. You can also work out kwh from watts in reverse — divide the energy in kWh by the hours to find the average watts — which is exactly how you check whether a battery can sustain a load. Whether you are converting watts to kw hours or going back from kWh to watts, the same 1,000 factor applies.
How to Convert kWh to Watts
To go the other direction, use watts = kWh × 1,000 ÷ hours. This answers the common kwh to watt question — how many watts can my battery deliver for a given backup time — and it is the core of every kwh to watts calculation.
For example, a 10 kWh battery supporting a 4-hour backup window can sustain 10 × 1,000 ÷ 4 = 2,500W of continuous load.
A dawnice 5.12 kWh pack (48V 100Ah) spread over an 8-hour night supports 5.12 × 1,000 ÷ 8 = 640W of average load — enough for lighting, a fan, phone charging and a small TV through a typical Nigerian outage.
These figures are average continuous power. Inverters and appliances draw a surge at startup, so size for the worst 5–10 seconds, not just the average — this is where the kwh to watts conversion meets real-world derating.
kWh vs kW: What’s the Difference?
Think of electricity like water in a pipe. kW (kilowatts) is the flow rate — how fast energy is delivered at any instant. kWh (kilowatt-hours) is the total volume — the amount of water that passed through over time. Power (kW) is a rate; energy (kWh) is a quantity.
So how many watts in a kwh? 1 kWh is exactly 1,000 watts running for 1 hour — it is not a fixed number of watts. The same 1 kWh could be 100W for 10 hours, 500W for 2 hours, or 2,000W for 30 minutes. The answer to “how many watts are in a kwh” always depends on time. And how many kwh in a watt? One watt running for one hour consumes 0.001 kWh.
The conversion between the two units is always kWh = kW × hours. Since 1 kW = 1,000 watts, converting kw to watts means multiplying by 1,000, and converting watts to kw means dividing by 1,000.
For a deeper look at how these units drive solar and storage design, read our guide on understanding energy conversion from kWh to kW in solar and energy storage systems.
Why kWh Matters for Battery Sizing
Battery capacity is rated in kWh; loads are rated in watts. Runtime is simply hours = battery kWh × 1,000 ÷ load watts. A 5.12 kWh pack on an 800W load runs 5.12 × 1,000 ÷ 800 = 6.4 hours — before any depth-of-discharge allowance.
In Nigeria, grid supply is intermittent, and serious backup planning assumes 8–12 hours of autonomy per day. That changes sizing completely: a shop drawing 1,500W for 10 hours needs 15 kWh of usable storage — around three dawnice 5.12 kWh packs, or one 10.24 kWh pack plus solar topping up during the day.
dawnice offers 5.12 kWh (48V 100Ah), 10.24 kWh (48V 200Ah) and 200 kWh containerized systems, so you can scale from a single retail backup to a commercial BESS on the same 48V / 51.2V architecture. Every product’s kWh rating is the number that matters for sizing — watts alone cannot tell you how long a battery will last.
Use the calculator above with your real load watts and target backup hours. The result in kWh is the minimum battery capacity to quote — then add your safety margin and chosen depth of discharge.
Why Use This Watts to kWh Calculator?
Right-size your battery
Enter your load in watts and backup time in hours — the calculator returns the kWh you need, so you quote the right pack the first time.
Compare battery systems
Brands quote Ah, V and kWh. kWh unifies them: a 48V 100Ah pack and a 51.2V 100Ah pack are 4.8 and 5.12 kWh respectively — compare on energy, not ampere-hours.
Estimate runtime instantly
Known battery kWh and load watts? The calculator converts to hours in real time — perfect for checking how long a 5.12 kWh pack carries an 800W load (≈6.4h).
Plan solar + storage
Match daily solar generation in kWh against battery capacity in kWh to design hybrid systems that actually cover the night.
Built for African grid conditions
Nigerian blackouts rarely announce themselves. Sizing for 8–12 hours of autonomy — the default assumption behind dawnice’s 5.12, 10.24 and 200 kWh systems — keeps businesses running through multi-hour outages.
Watts to kWh FAQ
How do you convert watts to kwh?
How many watts in a kwh?
How to calculate kwh from watts?
How many watts is 1 kwh?
What is the difference between kwh and kw?
How long will a 5.12kWh battery run my load?
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