How Much Water Do I Need Today?
The Safety Edit™
How much water
do I need today?
A practical wilderness hydration calculator. Adjust the inputs and get a personalised estimate.
Weight
Volume
About you & your day
Body weight
70kg
Water needs scale with body mass
Hours of activity
4hrs
Total time out, including breaks
Activity intensity
Temperature
Altitude
Pack / load weight
Your estimated total
—L
— litres
— pints
— fl oz
Including a 20% safety buffer — always carry a little more than you think you need
Breakdown
Activity hydration
—L
Cooking / camp use
—L
Estimated for trips 6 hours or more
Safety buffer (20%)
—L
Always build this in — conditions change
How many bottles
—
× 500ml / 17 fl oz bottles
—
× 1 litre / 34 fl oz bottles
Don't forget electrolytes. At this intensity or temperature, water alone isn't enough — you'll lose sodium, potassium, and magnesium through sweat. Pack electrolyte sachets and use them, especially on trips of 2 hours or more.
High water requirement. Carrying this much water will add significant weight — 1 litre weighs 1kg (about 2.2lbs). If you can't carry it all, plan your route around a reliable water source and bring a filter or purification tablets.
Hydration reminders
—Drink before you're thirsty — thirst is already a sign of early dehydration
—Pale straw-coloured urine = well hydrated. Dark yellow = drink more
—Cold weather reduces thirst but not your water needs
—Altitude increases water loss through breathing — drink more at height
—If using a natural water source, always filter and purify before drinking
What to carry:
water safety essentials
Our recommendations for wilderness hydration — filters for on-trail drinking, purification tabs as backup, and electrolytes for longer days.
Gravity filter · Basecamp
Travel Berkey Water Filter System
Gravity-fed stainless steel filter removes 200+ contaminants without electricity. 1.5-gallon (5.7L) capacity — ideal for camp use, van life, or basecamp stays. Black Berkey filter elements have an exceptionally long lifespan.
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Squeeze filter · On trail
LifeStraw Peak Series — Collapsible Squeeze
Ultra-lightweight collapsible bottle with a 0.2-micron built-in filter. Removes 99.999999% of bacteria and 99.999% of parasites. Use as a bottle, squeeze into a container, or drink directly. 650ml / 22 fl oz and 1L / 34 fl oz options.
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Electrolytes · Long days & heat
LMNT Electrolyte Sachets
No sugar, no artificial ingredients. Each sachet contains 1,000mg sodium, 200mg potassium, 60mg magnesium. Individual sachets are compact and easy to pack. Available as a variety pack to try flavours first.
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Purification tabs · Emergency backup
Aquatabs Water Purification Tablets
The world's most widely used purification tablet. Used by NATO, the British Army, and major aid agencies. Kills bacteria, viruses, and cysts within 30 minutes. 5-year shelf life. Keep a strip in your kit at all times.
View on Amazon →
Looking for a full outdoor safety kit? We've put together a curated guide covering everything worth carrying in the wilderness — from personal alarms to water safety to navigation.
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