Food and Water Storage Calculator for Your Family

A family of two adults and two children needs 360 gallons of water and roughly 385 pounds of grain, 96 pounds of dry beans, 60 pounds of powdered milk, 32 pounds of sugar, 16 pounds of oil and 4 pounds of salt to get through three months. The water follows Ready.gov's gallon per person per day. The food follows the University of Georgia Extension's yearly staples list for one adult, scaled down for children. Change the numbers below to fit your own house.

Once you have the numbers, the next job is putting the staples away so they keep. Our step-by-step guide shows how to pack rice, beans and wheat in Mylar bags and buckets.

How the water figure is worked out

Ready.gov tells households to store at least one gallon of water per person per day, for drinking and sanitation. A normally active person drinks about three quarters of that. The rest goes to brushing teeth, washing hands and wiping down dishes. The calculator multiplies that gallon by every head in the house, babies included, and by the number of days you chose.

The same Ready.gov page says children, nursing mothers and sick people may need more, and that in very hot weather water needs can double. Tick the hot-climate box if you live in the South or the desert Southwest, or if the outage you are planning for is a summer hurricane. It doubles the total.

The gallon is a floor. It does not include cooking water for a pantry heavy in dry beans and rice, flushing a toilet, or a garden. Utah State University Extension puts drinking needs at about a tablespoon of water for every 15 calories eaten, which is two and a half quarts a day on a 2,200-calorie diet, so even drinking alone can run past half the allowance. Our guide to how much water to store per person breaks the gallon down further and shows where else a house hides usable water.

Water weighs about 8.34 pounds a gallon, and the result shows the weight because it decides where the water can go. Three months for four people is a ton and a half. That belongs on a concrete slab or a ground floor, never on a wooden upper floor or an attic joist. The barrel count assumes the common 55-gallon drum.

How the food figures are worked out

The food side uses the University of Georgia Extension's bulk staples list, written by two of its food safety specialists from FEMA and Church of Jesus Christ emergency preparedness materials. It suggests these amounts per adult, per year: 240 pounds of wheat, 240 of corn, 120 of soybeans, 75 of powdered milk, 20 of fats and oil, 5 of iodized salt and 180 grams of vitamin C. Its supplementary list adds 40 pounds of white sugar. The calculator treats the wheat and corn together as one grain line of 480 pounds, the soybeans as any dry bean, and divides each line by 365 to get a daily amount for one adult.

Children are counted as shares of an adult. The federal calorie estimates in the Dietary Guidelines for Americans, reprinted by the Merck Manual, put children aged 2 to 6 at 1,000 to 1,800 calories a day, against 1,600 to 3,000 for adults aged 19 to 60. That is about half. Children 7 to 18 span 1,200 to 3,200 calories, so the calculator gives 7- to 12-year-olds three quarters of an adult share and counts anyone 13 or older as an adult, because an active teenage boy can top the chart. These shares are our rounding of the federal ranges. A house of growing children is better off erring high.

Each line then gets multiplied by the shares and the days. For the family above, two adults plus one child at 0.75 and one at 0.5 make 3.25 shares. Grain works out to 480 ÷ 365 × 3.25 × 90, which is about 385 pounds. The bucket count divides the grain by 34 pounds, because a five-gallon bucket of wheat or rice filled to an inch below the rim holds a little under 35, using the pouch weights in the Church's long-term storage guide.

The dry-food floor line, and why it is so much smaller

The last cell in the result is a different measure. Utah State University Extension, which has analyzed more than 10,000 home food storage systems in Utah, takes one pound of dry food per person per day as the base of a storage program. A pound of dry beans, flour, wheat, rice, sugar, pasta or dried skim milk gives about 1,600 calories. USU is frank that this will not feed a hard-working large man, though it will quiet hunger for every member of a family.

Set beside the Georgia list, the gap is wide. Georgia's grain, beans, milk and sugar come to nearly two pounds a day per adult, which at 1,600 calories a pound is roughly 3,100 calories before a drop of oil. That is generous for most adults and right for someone splitting wood and hauling water. The floor line is what to aim for if space or budget forces a choice, with everything above it as margin.

I read the two lines as a range. Anything under the floor is a gap to close first. A store between the floor and the full list feeds a family through ordinary work. Reaching Georgia's amounts means you have room for guests, spoilage and the hard physical days an outage brings.

A worked example for one adult

The table shows the calculator's output for a single adult at three lengths. Multiply by your own adult shares to check the tool against a pencil, or to plan without the script.

For the family in the opening, multiply the three-month column by 3.25 for the food and by 4 for the water. Small differences from the result box come from rounding the table.

Two weeks, three months or a year

Two weeks is the length most official guidance stops at, and it is the one to finish first. At that size, the staples list matters less than the meals you already cook. Canned meat, soup, peanut butter, crackers and cereal need little water or fuel and nobody has to learn a new recipe. Ready.gov's food page lists exactly these. Treat the calculator's grain and bean lines as a check on calories, then buy the equivalent in food your family eats. Water is the harder half here: 56 gallons for a family of four is ten or eleven cases of jugs, or one barrel.

Three months carries a household through a job loss, a long illness or a slow regional recovery. This is where the sealed staples start to pay, because 385 pounds of grain costs far less in buckets than in canned goods. Our page on three months of food for a family of four walks through mixing an everyday shelf with a smaller sealed layer, and that mix is what I would follow. Water at this length outgrows most houses, which is where treatment comes in.

A year is the old Church goal and the reason long-term packing exists. USU found that families in Utah who held a year in November often had only part of it by May, after drawing on it through the winter with no garden to replace it. Its advice is to store eighteen months so that a full year is always on hand. At this length, a survival garden and a cool place to keep its harvest become part of the food plan, and the calculator's grain line becomes the calories the garden does not cover.

When the water total is more than you can hold

Run the calculator for a year and the water figure stops being a storage number. Four people need 1,460 gallons, about 27 barrels and more than six tons. Almost nobody stores that. The working plan is a stored base for the first weeks plus a way to make outside water safe after that.

• Store enough clean water for at least two weeks, which for most families means jugs plus one or two barrels.
• Know where the next water comes from: a well with a hand pump or generator, a rain barrel off the roof, a creek or pond within walking distance.
• Keep the means to treat it. Our guide to what emergency water filters remove covers settling and filtering, and our bleach dosing guide gives the EPA amounts per gallon.

Stored water also needs rotating. Ready.gov says to replace water you bottled yourself every six months. Commercially sealed water can stay in its original container in a cool, dark place.

Adjusting the result for your own household

The calculator counts everyone 13 and over as one adult share, and that hides real differences. Adults past 60 need fewer calories, about 1,600 to 2,600 a day by the federal table, so a retired couple can trim the food lines by a fifth and still be covered. A household that heats with wood or works land should go the other way and store every pound the calculator shows.

Special diets come before everything else in the plan. A store built around wheat is of no use to someone with celiac disease, and a diabetic in the house needs the sugar line replaced with foods their doctor approves. Formula and baby food for a child under two get their own list, sized to the baby's age, because the Georgia staples list leaves them out and formula has hard expiry dates.

Vitamins fill the holes the staples leave. Georgia's list includes 180 grams of vitamin C per adult a year, to be rotated every two years, and suggests storing 365 multivitamin tablets per person per year. Cut those to your length the same way: about 90 tablets a head for three months.

Turning pounds into shelves

The pounds are only useful once they are in containers that keep. Dry grain and beans go into Mylar bags with oxygen absorbers, inside food-grade buckets, which our packing guide covers from the first bag to the sealed lid. How long each staple lasts once packed is in our food storage shelf life chart. White rice and wheat run past 30 years when sealed and kept cool, while powdered milk in a box lasts months.

Heat is what shortens all of it. USU Extension wants the storage area kept above 32 and below 70 degrees, dry, and off the floor, and it notes that a room 9 by 12 feet with a 10-foot ceiling holds eighteen months of food for a family of six. Most families need much less space than that for three months, a closet floor or one basement wall.

A freezer full of meat adds to the supply only while the power holds. If you count it, read our guide on what to keep when the freezer loses power so you know which shelf to eat first.

My take: where I would start

I would run the calculator twice: once for two weeks and once for three months. The two-week result is the shopping list for this month, bought as the canned food and jugs your family uses anyway. The three-month result is the target for the year ahead, built a week at a time with each paycheck.

For the sealed layer, I would aim for the floor line first and treat the full Georgia list as a later goal. Rice, pinto beans and rolled oats are the grains and beans I would buy before wheat and corn, because they need no mill and most families already eat them. Add the oil, salt and sugar the calculator shows, and the powdered milk only in the amount you will actually drink before it goes stale.

Then I would take the water figure seriously, because it runs out first. Store the two-week amount before buying a single bucket of grain, and know where the next gallon comes from. When those are in place, pack your first bucket of staples.

This calculator gives an estimate from published guidance. It does not account for medical conditions, pregnancy or heavy labor, and it is not dietary advice for any one person.

Sources

• Ready.gov: Water
• Ready.gov: Food
• University of Georgia Extension: Preparing an emergency food supply, long term food storage
• Utah State University Extension: Food storage in the home
• Merck Manual: Estimated calories needed by age, sex and activity level (Dietary Guidelines for Americans 2020-2025)
• The Church of Jesus Christ of Latter-day Saints: Long-term food and water storage

How we write: we work from extension-service, university and government guidance and say what we have not tested. See our editorial policy.