December 3, 2025 - This convenient calculator gives you the estimated runtime for any of our UPS models, showing you the total load in watts and the runtime in minutes.

March 14, 2025 - The UPS Runtime Calculator works out the runtime you will get for any UPS battery configuration. Just enter the load, the battery capacity and quantity.

Use this calculator to estimate the runtime of a 650VA UPS.

Manual/Generic Calculator: Calculate the estimated run time or battery backup time of any uninterruptible power supply (UPS) using the load in watts, the device load (in watts), number of batteries, battery voltage, and battery amp hours.

Calculate your UPS backup runtime with our UPS Runtime Calculator. Determine how long your UPS will power your equipment based on VA rating and load.

Use this tool to estimate the runtime of your APC UPS based on your equipment's power consumption. Enter your APC UPS capacity (VA) and the load in watts to calculate the estimated runtime during a power outage.

Find the perfect UPS system in two easy steps! Calculate the total power consumption of connected devices then choose a runtime so get your recommendations.

Calculate how long your UPS will run during a power outage. Enter your UPS power supply capacity and load to get accurate runtime estimates.

How Much Power Will Your UPS Use? Choose the right UPS, uninterruptible power supply, based on your total power consumption, Eaton UPS Selector

Divide the rating in VA of the UPS by the rating in VA of the load. If the result is less than 1.3 these calculations cannot be used. Where the result of the above division is greater than 1.3 but less than 3, multiply this result by 1.3 x the full load backup time of the UPS to obtain the ...

Formula: minutes ≈ (V × Ah × strings × efficiency × safety × 60) ÷ load (W). Use the calculator below, compare minutes to your shutdown or generator-start target, then size amp-hours in the UPS battery calculator.

March 14, 2025 - Enter the number of devices and their respective amps, volts, and quantity to calculate the total VA of your UPS load. This calculation will help you determine the appropriate UPS size for your devices.

These interactive runtime graphs make it easy to see the amount of battery runtime available with or without optional battery packs. Click your UPS below for runtimes.

This calculator helps you find out the amount of time that the UPS will be able to keep the connected equipment running in the event of a power failure. ... Runtimes based on testing fully-charged, new batteries at normal operating conditions.

December 5, 2021 - So I'd try a new battery or use a DC clamp meter to measure current draw from the battery, then calculate out how much of that 5Ah is available before the UPS shuts down. Certainly it will be below 5Ah just due to drawing such a large load off of it, making it dubious that they state an "650" UPS, which I assume means 650VA, runs off a little 5Ah battery. In other words I would pick an ups with a larger battery or pair of two 12V batteries for long runtime, or rig something yourself to connect a larger battery to that UPS, IF the charging circuit doesn't have a problem with it, and IF the UPS doesn't overheat from the extended running time.

March 9, 2026 - Get a quick UPS runtime estimate from load in watts and VA. Learn the formula, derating and examples to size backup time and select the right UPS.

APC Smart-UPS Runtime Chart for SUA Models.

March 16, 2022 - Your runtime will be 0.35/0.21 which is 1.66 hours. This is really rough maths and leaves a lot of detail out around inverter efficiency, power factor, battery condition etc. I wouldn't be surprised if it barely makes it to 1 hour.

September 28, 2024 - This guide teaches you how to estimate the uninterruptible power supply hours your system can provide and how to maximize your UPS operation time.