Blackout Preparedness Calculator: What You Need for X Days

Calculate Your Personal Needs

Every household is different: number of people, babies, elderly, pets, medication needs. This calculator provides baseline values — adjust for your situation.

Water: The Most Critical Resource

Basic need: 2 liters of drinking water per person per day

Total needs by household size and duration:

People	3 Days	7 Days	14 Days
1 person	6L	14L	28L
2 people	12L	28L	56L
4 people	24L	56L	112L

Additional needs: Cooking (+0.5L/person/day), Basic hygiene (+0.5L/person/day), Infant (+1L extra/day), Pet (0.25-1L/day depending on size)

Food: Calorie Needs During a Blackout

Basic need: 2,000 calories per adult per day (reduced activity)

Recommended 2-week stock (2 people):

Category	Amount	Examples
Grains/pasta	4 kg	Rice, pasta, oats
Legumes	2 kg	Lentils, beans, chickpeas
Canned goods	20 items	Tuna, vegetables
Oil/fat	1 L	Olive oil, coconut oil

Power: What Devices Use How Much Energy

Device	Wattage	Hours/day	Wh/day
Smartphone charging	15W	2h	30 Wh
LED lamp	10W	5h	50 Wh
Laptop	45W	4h	180 Wh
Small fan	20W	8h	160 Wh

Typical daily need for 2-person household: approx. 200-400 Wh

Power stations for 7 days:

• Minimum: 500 Wh
• Comfortable: 1,000 Wh
• Long-term: 2,000+ Wh

72-Hour Minimum Setup

For one person for 3 days:

• Water: 9 liters
• Food: approx. 1 kg dry goods + canned food
• Power: 20,000 mAh power bank
• Light: headlamp + 2 spare batteries

Cost: approx. €50-80 for the absolute minimum.

Conclusion

With the right calculations, you know exactly what you need for your household — without overspending or under-preparing. Start with the 72-hour minimum and build toward 14 days.