How Long Will a 1,000VA UPS Last?

Answer
14m at half load (300 W)

A typical 1,000VA UPS is rated about 600 W and uses 2 × 12 V 7 Ah batteries. At half load (300 W) it runs about 14m. Lighter loads last much longer: about 33m with an office PC and monitor (150 W) and 6h 13m with just a router and modem (20 W).

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W
Sum of connected equipment.
W
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V
Two 12 V batteries = 24 V.
Ah
%
Runtime
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How we calculated this

    For estimating and educational purposes only. Results are approximate and are not a substitute for a licensed professional, the manufacturer's instructions or your local code. Disclaimer

    1,000VA UPS runtime by load

    EquipmentLoadRuntimeUPS load
    Router + modem20 W6h 13m3%
    Router, modem + 2 cameras50 W2h 4m8%
    Laptop + router100 W54m17%
    Office PC + monitor150 W33m25%
    NVR with 8 cameras200 W24m33%
    Desktop PC + 2 monitors300 W14m50%
    Gaming PC (light load)450 W9m75%
    Gaming PC (gaming)600 W6m100%

    Estimates for new batteries at 25 °C and 90% inverter efficiency, using Peukert's law (k = 1.2). Battery packs vary by brand: check yours and enter it in the calculator. Batteries older than 3 years can deliver half of this.

    Frequently asked questions

    How long will a 1,000VA UPS run a computer?

    About 33m for an office PC with a monitor (150 W) and 14m for a desktop with two monitors (300 W).

    Why does half the load give more than double the runtime?

    Lead-acid batteries deliver less of their rated capacity at high current (Peukert effect). At light loads you get close to the full Wh; at heavy loads much less.

    How much load can a 1,000VA UPS take?

    Its rating is about 600 W. Keep the load under 80% (480 W) so the inverter and batteries are not stressed.

    Open the full calculator: UPS Runtime Calculator →