Enter the distance to your next water source, your pace, the heat, and the climb — get how much water to carry and what it weighs in your pack.
Rough trail pace: 2 mph (3 km/h) is typical with a pack.
Liters per hour on easy, cool terrain. 0.5 L/hr is a common baseline.
Extra reserve — enter liters (0.5) or a percentage (20%).
Estimate only. Real water needs swing with sun, wind, humidity, fitness, and how much you sweat — always carry a margin, and never skip a reliable source counting on the next one.
Post your route and get water-source beta, carry strategies, and pack-weight tips on the HikingGear Forum — real hikers, real trips.
Most hikers drink somewhere between 0.5 and 1 liter of water per hour on the move. This tool starts from a base drinking rate (default 0.5 L/hr on cool, easy ground) and scales it up for the two things that push it hardest — heat and climbing — then multiplies by the time on the leg, which it works out from the distance to your next source divided by your pace.
Heat matters most: above about 20 °C (68 °F) the rate climbs by roughly 5% for every degree, so a hot afternoon can easily double your needs versus a cool morning. A steep climb adds more on top, scaled by how fast you're gaining elevation. Faster pace shortens the leg but packs the effort into less time — the total water is driven by the hours, not just the miles.
Then there's the weight. Water is heavy: 1 liter weighs about 1 kg (2.2 lb). Carrying an extra 3 liters "just in case" adds nearly 7 lb to your pack, which is why matching your carry to the actual gap between reliable sources — plus a sensible buffer — is worth doing rather than always topping off to the brim.
A common baseline is about half a liter (17 oz) per hour in mild conditions, rising toward 0.75–1 L/hr in heat or on sustained climbs. Over a mile that's roughly 0.25–0.5 L at a normal 2 mph pace. This calculator takes your base rate and scales it for temperature and elevation gain, so the per-hour figure it shows is tuned to the leg you're planning, not a flat guess.
Yes. Sweat losses climb steeply once it's warm. The model leaves the rate unchanged up to about 20 °C (68 °F), then adds roughly 5% per degree above that, capping at three times the base. A leg you'd finish on 1 liter at dawn can want 2+ liters in the afternoon heat — plan around the hottest part of the day, not the average.
Water weighs about 1 kilogram per liter, or 2.2 pounds. So 2 L is ~2 kg (4.4 lb) and 4 L is ~4 kg (8.8 lb). The tool shows the added pack weight next to the volume so you can weigh (literally) carrying more against the risk of running short between sources.
On anything remote, yes. A fixed reserve (say 0.5 L) or a percentage (say 20%) covers a slower-than-planned leg, a dry or fouled source, or a hotter day than forecast. Enter it in the buffer field and it's added on top of the calculated need. When a source is uncertain, treat it as unreliable and carry through to the next one you trust.