Free Tool

Battery Runtime Calculator

Work out how long your camera or gear battery will last. Enter capacity in Wh or mAh, set device power draw and efficiency loss, and get a realistic runtime estimate.

Battery Capacity
Check your battery label or spec sheet. Common: 16 Wh (Sony NP-FZ100), 98 Wh (V-mount)
Printed on the battery or in product specs
Usually 3.6 V, 3.7 V, 7.2 V, or 7.4 V
Device Draw
Typical: 4-8 W (mirrorless camera), 15-25 W (cinema camera), 2-5 W (field monitor)
12%
Accounts for heat, voltage conversion and regulation losses
Multi-battery (Optional)
Total runtime = per-battery runtime × battery count
Ctrl+Enter to calculate
Example Output
Runtime Per Battery
2:04
2 h 4 min per battery
Total Runtime
4:07
4 h 7 min with 2 batteries
Battery Capacity
16.4 Wh
Effective Capacity
14.4 Wh
After 12% efficiency loss
Device Draw
7 W
Batteries
2
Quick Scenarios
Draw Per Battery Total
5 W2:535:46
10 W1:272:53
20 W0:431:26
40 W0:220:43
Example: Sony NP-FZ100 (16.4 Wh) powering a mirrorless camera at 7 W with 12% efficiency loss and 2 batteries. Enter your own values and click Calculate to see your personalised result.
Runtime Per Battery
--:--
Battery Capacity
--
Effective Capacity
--
Device Draw
--
Batteries
--
Quick Scenarios
Draw Per Battery Total
Note: Real-world runtime varies with ambient temperature, screen brightness, recording resolution, stabilisation, autofocus usage and battery age. Treat these figures as estimates, not guarantees.

How to Use

Step 1
Enter battery capacity
If you know the Wh rating, enter it directly. Otherwise, switch to "mAh + Voltage" and enter both values from your battery label. The calculator converts automatically.
Step 2
Set power draw
Enter how many watts your device uses. Check your camera specs or manual. Adjust the efficiency slider to account for real-world losses from heat and voltage conversion.
Step 3
Read your runtime
Hit Calculate to see per-battery and total runtime. The quick scenarios table shows how runtime changes at different power draws so you can plan accordingly.

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