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LC76 SW 1HZ · Field Calculator

Water Budget Calculator

Daily consumption, tank autonomy & resupply planning

Main tank: 70 L
People: 2
Resupply: 5 days
Daily use: — L/day
Autonomy: — days
Tank summary — current capacity and projected figures
Total capacity
70 L
Usable tank volume
Available now
70 L
From current fill level
Daily consumption
— L
All activities combined
Autonomy
— days
Days to reserve threshold
Tank settings — adjust to match your actual containers and fill level
Total tank capacity
70 L
Total usable litres across all containers (built-in tank + jerry cans + collapsibles). Typical expedition setup: 40–120 L.
Current fill level
100%
Percentage of total capacity currently available. Set to your actual level before calculating.
Number of people
2
Total people sharing the water supply. Consumption scales per person.
Reserve threshold
20%
Minimum reserve — do not plan to consume below this level. Autonomy days calculated to this threshold, not empty.
Resupply interval target
5 days
How often you plan to resupply. Used to show required capacity. Remote Africa: plan for 7–14 days between reliable sources.
Consumption scenario — select a scenario then adjust individual activities below
Activity L/person/day People Notes L/day
Total daily consumption — L
Water budget results — based on current settings
Available water
— L
Current fill above reserve
Daily consumption
— L
All activities combined
Autonomy
— days
Days to reserve threshold
Per person / day
— L
Individual daily allocation
Resupply needed
— L
For your -day target
Gap to target
— L
Additional containers required
Tank level over time
Empty Reserve (20%) Full
Warning thresholds — field decision guide
Action levels — adjust consumption and resupply plans accordingly
Comfortable
Autonomy > 3 days above reserve. Normal consumption. No action.
Watch
Autonomy 2–3 days. Monitor use. Identify next resupply. Reduce non-essential washing.
Conserve
Autonomy 1–2 days. Drinking and cooking only. No personal washing from tank. Source water urgently.
Critical
At or below reserve. Drinking only. Stop travel and resupply immediately or treat surface water.
Calculation breakdown — full detail
● Water Budget — Full Detail
Total capacity
Current fill
Available above reserve
People
Daily consumption
Per person / day
Autonomy (to reserve)
Required for resupply interval
Gap (extra capacity needed)
Activity reference — typical field consumption values per person per day
These are conservative overland estimates for hot, remote conditions. Actual use varies significantly. Track your real consumption over the first few days and adjust sliders accordingly.
Activity Minimum Typical Liberal Notes
Drinking2.0 L3.0 L4.0 LIncrease in heat (38°C+). Physical exertion: +1–2 L. Minimum 2 L strictly for hydration.
Cooking (meals + coffee/tea)0.5 L1.0 L2.0 LRehydrated/boiled meals ~0.5 L. Fresh cooking or pasta: 1.5–2 L. Coffee/tea adds ~0.4 L/person/day.
Dishes & utensils0.3 L0.5 L1.0 LScout method: scrape + rinse. Basin wash: 1 L total for 2. Minimal rinse: ~0.3 L.
Personal hygiene (face, hands)0.2 L0.5 L1.0 LHand wash before meals critical for hygiene. Face wash & basic hygiene. No wet wipes counted here.
Body wash (partial or full)1.0 L3.0 L6.0 LBucket shower: 4–6 L. Strip wash: 1–2 L. On strict ration: wet cloth + biodegradable soap.
Laundry (partial, hand wash)0.0 L0.5 L2.0 LDaily socks/underwear hand rinse: ~0.5 L. Full hand wash: 2–4 L. Not every day in the field.
Vehicle / equipment rinse0.0 L0.0 L3.0 LShared total, not per person. Only where water is freely available. Never from drinking supply.