UPS Backup Time Calculator
Find out how long your UPS or battery will last during a load-shedding break. Enter battery capacity, voltage, number of batteries and your load in watts to get an estimated backup time in hours, computed instantly and free.
Note: Actual backup also depends on the battery age and health. An old battery will give less backup.
How to use
- Enter the battery Ah (written on the label, e.g. 200Ah), voltage and number of batteries.
- Add the watts of the things you want to run — click the chips or type the total load yourself.
- The result will update instantly: backup time (hours + minutes) and usable watt-hours.
Formula: Usable Wh = Ah × V × Batteries × Efficiency ÷ 100. Backup hours = Usable Wh ÷ Load (W). For UPS, battery or solar work: Azlaan Electric AC Solar Center, Faisalabad — 0300-8987448.
Good to know
- Real backup time is usually less than the estimate — old batteries lose capacity.
- Add up all connected watts (fan, lights, router) for an honest load figure.
- Heavy loads like motors and irons drain batteries much faster than LED lights and fans.
- If the result is too short, adding one more battery of the same voltage helps.
Frequently Asked Questions (FAQ)
What does the UPS backup time calculator calculate?
How long your battery will last — backup time in hours and minutes plus usable watt-hours, from battery Ah, voltage, battery count and load.
How do I enter my load?
Click the wattage chips for common appliances or type your total load yourself.
What inputs does the backup time calculator need?
Battery capacity in Ah, battery voltage, the number of batteries, inverter efficiency percent and your total load in watts. Backup hours equal usable watt-hours divided by the load.
Why might my real backup time be shorter?
Battery age and health change the result — an old battery gives less backup than the same size new one. Treat the result as a planning estimate.