Shelter Capacity Calculator
Calculate how many people can safely shelter in your space and plan appropriate arrangements for emergency shelter-in-place scenarios.
Calculate Your Shelter Capacity
Understanding Shelter Space Requirements
Emergency shelter planning involves more than just finding a room. The amount of space needed per person varies dramatically based on the duration of stay, type of emergency, available facilities, and the physical and psychological needs of those sheltering.
Space Standards by Duration
| Duration | Minimum (sq ft/person) | Comfortable (sq ft/person) | Ideal (sq ft/person) |
|---|---|---|---|
| Under 24 hours | 15-20 sq ft | 30-40 sq ft | 50+ sq ft |
| 1-3 days | 25-35 sq ft | 50-60 sq ft | 80+ sq ft |
| 3-7 days | 40-50 sq ft | 70-80 sq ft | 100+ sq ft |
| 7+ days | 60+ sq ft | 100+ sq ft | 150+ sq ft |
Choosing the Right Shelter Location
For Tornadoes and Severe Storms
- Lowest floor of the building (basement ideal)
- Interior room away from exterior walls
- No windows or glass
- Under sturdy furniture or reinforced area
- Away from heavy objects that could fall through ceiling
For Chemical/Biological Threats
- Upper floors (many chemicals are heavier than air)
- Room with minimal openings to seal
- Internal room without exterior walls preferred
- Near bathroom for water supply
- Materials to seal doors, windows, vents
For General Shelter-in-Place
- Room with bathroom access or nearby
- Adequate ventilation
- Access to stored supplies
- Communication capability (cell signal, radio)
- Comfortable for expected duration
Calculating Usable Space
Total square footage doesn't equal usable space. You must account for:
Furniture and Fixed Items
- Bed (twin): 20 sq ft
- Bed (queen/king): 35-45 sq ft
- Couch: 20-30 sq ft
- Table and chairs: 20-40 sq ft
- Desk: 15-25 sq ft
Emergency Supplies
- Water storage (7 days, family of 4): 8-12 sq ft
- Food storage: 4-8 sq ft
- Portable toilet: 6-9 sq ft (with privacy)
- Generator (if inside for any reason): NEVER - CO hazard
Circulation Space
People need to move around. Plan for walkways and access:
- 3-foot minimum walkways
- Access to exits
- Space to stand and stretch
Special Considerations
Children
Children need less physical space but require:
- Play area to reduce stress
- Safe zones away from hazards
- Supervision sightlines
- Age-appropriate sleeping arrangements
Elderly and Mobility-Impaired
- Wider pathways (36+ inches)
- Ground-level sleeping if possible
- Access to bathroom
- Space for mobility equipment
Pets
- Dogs: 4-15 sq ft depending on size
- Cats: 3-6 sq ft (plus litter box space)
- Separation area if pet is stressed
- Away from exits to prevent escape
Ventilation and Air Quality
Sealed shelters require careful consideration of air supply:
- Minimum ventilation: 3 CFM per person for non-sealed rooms
- Sealed rooms: Limited duration (2-4 hours without supplemental air)
- Carbon dioxide buildup: Monitor in sealed spaces
- Never run generators indoors: CO poisoning is deadly
Frequently Asked Questions
How much space does each person need in an emergency shelter?
Minimum standards recommend 20 square feet per person for short-term emergencies and 40-60 square feet for extended stays. FEMA and Sphere humanitarian standards suggest 40 sq ft minimum. For comfort in home shelter-in-place scenarios lasting more than a day or two, plan for 100+ square feet per person if possible.
What is the best room to shelter in place?
It depends on the threat: For tornadoes, choose interior rooms on the lowest floor without windows (bathroom, closet, basement). For chemical threats, choose upper-floor interior rooms that can be sealed. For general emergencies, choose a room with water access, bathroom nearby, and space for supplies and sleeping.
How long can you shelter in place?
With proper supplies, you can shelter in place for days to weeks. Limiting factors are usually water, food, sanitation, and psychological stress. A well-prepared home can support shelter-in-place for 2+ weeks. Sealed rooms for chemical threats should be limited to 2-4 hours without supplemental air systems.
Can I host other families during emergencies?
Yes, with planning. Calculate capacity based on 40-60 sq ft per person for multi-day stays. Ensure adequate water, food, and sanitation for all. Establish house rules and privacy arrangements. Having too many people creates stress, sanitation issues, and supply problems.