Enter your battery's Ah and voltage rating and the tool's typical draw to estimate runtime per charge.
Actual runtime varies a lot with how hard the tool is worked — light-duty use (drilling small holes) lasts far longer than sustained heavy load (continuous cutting or grinding).
A power tool battery's Ah rating combined with its voltage gives total stored energy in watt-hours, the same underlying math as our Ah to Wh converter — dividing that by the tool's typical draw under load gives a rough runtime estimate. Intermittent use (drilling a few holes here and there) stretches a charge much further than continuous heavy-load work like extended circular saw cuts.
Heavy sustained loads like cutting through thick material draw significantly more power than light intermittent use, and battery efficiency also drops somewhat as it discharges and in cold temperatures.
Not by itself — a higher voltage battery at the same Ah rating stores more total energy (Wh), but the tool itself is also usually designed to draw more power at higher voltage, so runtime depends on both figures together.