How This Is Calculated
Supplies total = people × per-person supply cost. Gear total = bags × per-bag gear cost. Total = supplies total + gear total.
- Supplies (water, food, meds, clothing) scale per person
- Gear (flashlight, radio, tools, first aid) scales per bag, not per person
These are starting assumptions, not fixed rules — adjust the inputs above to match your own family.
What This Calculator Estimates
Emergency preparedness is one of those tasks that tends to get postponed indefinitely because it never feels urgent until it suddenly is. Turning it into a specific dollar figure, rather than a vague someday project, is often the first real step toward actually doing it.
Putting together a family emergency kit involves two different kinds of costs. Some items — water, food, medication, a change of clothes — need to be duplicated for every person in the family, since one person's supply doesn't help anyone else. Other items — a flashlight, a radio, a multi-tool, a first aid kit — are shared gear that doesn't need to be bought multiple times just because there are more people in the household. This calculator keeps those two categories separate and adds them together based on your family size and how many actual bags you're assembling.
The result is a total estimated cost for either a single shared family kit or several individual bags, depending on how you set the numbers.
How the Calculation Works
This split mirrors how emergency planning guides commonly organize a checklist — consumables that run out and need replacing per person, and durable gear that gets packed once and mostly just needs periodic checking rather than repurchasing.
Per-person supplies are multiplied directly by the number of people in your family, since these costs scale with headcount regardless of how many bags you end up packing them into. Shared gear is multiplied by the number of bags instead of the number of people, since a flashlight or first aid kit serves everyone using that particular bag, not just one person. Adding the two totals together gives the full estimated cost of assembling the kit or kits.
One Shared Bag or One Per Person
There's no universally correct choice here — it depends on the specific risks a family is preparing for, how much storage space is available, and how much the family is willing to spend. This calculator is built to compare both approaches quickly rather than to recommend one over the other.
Families tend to fall into one of two approaches: a single, larger shared bag kept in one place, or smaller individual bags so that supplies are available even if the family gets separated. The shared-bag approach is usually cheaper, since gear costs are only paid once, but it depends on everyone being able to reach the same bag when needed. The individual-bag approach costs more, since gear gets duplicated across every bag, but provides redundancy — each person or vehicle has a complete kit rather than relying on one central bag.
A middle-ground approach some families use is one bag per vehicle or per location — home, car, workplace — rather than strictly per person. Setting the "bags" field to the number of locations rather than the number of people models this approach directly.
Building the Estimate Gradually
It's also worth deciding early which category — supplies or gear — to prioritize first if the full budget can't be spent all at once. Consumable supplies are the more time-sensitive purchase, since they're the items actually needed in the first hours of an emergency, while durable gear can often be acquired more gradually without leaving a family meaningfully less prepared in the short term.
This calculator works just as well for planning a purchase over time as it does for a single shopping trip. Running it once gives a total target; tracking what's already been bought against that target, category by category, turns "build an emergency kit" from a vague, often-postponed task into a specific dollar amount with a clear finish line. Many families find it easier to spread the cost across a few paychecks rather than buying everything in a single trip, and having a concrete total makes that kind of gradual budgeting easier to plan.
A Worked Example
Consider a family of four assembling one shared bag, with supplies estimated at $35 per person and gear estimated at $80 for the single bag. Supplies come to 4 × $35, or $140, and gear adds a flat $80, for a total of $220. Switching to one bag per person instead of a single shared bag keeps the supplies total the same at $140, since it's still based on the same four people, but multiplies the gear cost by four bags instead of one — 4 × $80, or $320 — bringing the new total to $460. The supplies cost stays fixed either way; it's the gear cost that roughly doubles or triples depending on how many separate bags are assembled.
What This Doesn't Include
It also doesn't include the time cost of actually assembling and organizing a kit, which for many families is the bigger barrier than the money itself.
It's worth setting a reminder to revisit the kit at least once a year, since food and water expire, batteries lose charge, and family size or needs can change well before anyone remembers to check.
This calculator doesn't account for supplies you already own, ongoing costs like replacing expired food or batteries over time, or specialized needs like infant supplies, pet supplies, or medical equipment for a family member with specific requirements. It also doesn't distinguish between a basic kit and a more elaborate one — the accuracy of the result depends entirely on how realistic your per-person and per-bag cost estimates are. Treat the total as a planning starting point, not a checklist of what to buy.
Frequently Asked Questions
Either works — this calculator treats "bags" and "people" as separate inputs specifically so you can model either approach. One shared family bag would use 1 for bags; one bag per person would set bags equal to your family size.
Supplies that get used up and scale with headcount — water, food, medication, a change of clothes — belong in per-person supplies. Shared tools that don't need to be duplicated per person, like a flashlight, radio, or first aid kit, belong in per-bag gear.
That depends heavily on how many days of supplies you want on hand and what you already own. This calculator doesn't assume a specific number — enter your own estimate based on a quick look at what a few days of water, food, and basic supplies would cost.
No, it calculates the cost of a bag built from scratch. If you already own some of the gear or supplies, subtract their value from the relevant field, or treat the result as the cost of filling any gaps.