This emergency food calculator converts household size and a chosen planning period into meal portions, snack portions and a no-cook food gap. It does not prescribe calories, tins or kilograms because appetites, ages, diets, pack sizes and health needs differ. Complete the calculation, then use the menu and pack worksheets to turn the result into food your household can actually eat.
Count a meal portion as the realistic amount one particular household member would normally eat. An adult portion and a child’s portion may both fill one meal slot, but they are not necessarily the same amount of food. Exclude infants, prescribed nutrition and anyone with a separately managed diet from the general calculation and plan their supplies in the dedicated section below.
The result is a planning estimate, not individual dietary or medical advice. During an incident, follow current instructions from the emergency services, health authorities and food-safety bodies.
Emergency food calculator: quick formula
Use the number of meals and snacks your household normally expects. Three meals per day is a convenient worked-example setting, not an official minimum or a rule for every person.
- Add the people included in the general meal plan.
- Choose the number of days you want the food supply to cover.
- Choose planned meal slots per person per day.
- Multiply people by days by meal slots.
- Calculate snacks separately using the household’s normal pattern.
- Compare the result with complete no-cook meal portions already stored.
Person-days = people × days
Total meal portions = people × days × meal slots per person per day
Total snack portions = people × days × snack portions per person per day
Step 1: calculate meal and snack portions
| Input | Your figure |
|---|---|
| Adults and older teenagers included | A = ________ |
| Children eating family meals | C = ________ |
| Other people using the general meal plan | O = ________ |
| Total people | P = A + C + O = ________ |
| Planning period | D = ________ days |
| Meal slots per person per day | M = ________ |
| Snack portions per person per day | S = ________ |
| Calculation | Working | Result |
|---|---|---|
| Person-days | P × D | ________ |
| Adult and older-teen meal portions | A × D × M | ________ |
| Child meal portions | C × D × M | ________ |
| Other general meal portions | O × D × M | ________ |
| Total meal portions required | P × D × M | T = ________ |
| Total snack portions required | P × D × S | ________ |
Keep adult, child and other portions separate while selecting food, even though they are added together for the headline number. This prevents a small child’s serving being counted as enough for an adult, or a large pack being divided into unrealistic label portions.
Worked example
A household has two adults and two children eating family meals. It chooses a three-day planning period, three meal slots per person per day and one snack portion per person per day.
| Calculation | Result |
|---|---|
| Person-days | 4 × 3 = 12 |
| Adult meal portions | 2 × 3 × 3 = 18 |
| Child meal portions | 2 × 3 × 3 = 18 |
| Total meal portions | 4 × 3 × 3 = 36 |
| Total snack portions | 4 × 3 × 1 = 12 |
The result means 36 person-specific meal slots and 12 snack portions. It does not mean 36 tins. One larger pack may provide several realistic portions, while a tin of fruit, packet of crackers or carton of long-life milk may be only one component of a complete meal.
Step 2: calculate no-cook coverage
The Cabinet Office Prepare guidance recommends non-perishable food that does not need cooking, but says the amount will vary with household circumstances. For a dependable core total, count only food that passes every part of this test.
- ☐ It can be eaten safely without mains-powered cooking.
- ☐ It does not require refrigeration before opening.
- ☐ It needs little or no preparation water.
- ☐ The intended person can open, prepare and eat it.
- ☐ It is suitable for that person’s allergies, health needs, texture needs and diet.
- ☐ The pack provides a realistic household portion rather than an implausibly small label serving.
- ☐ Any opened pack can be finished safely when refrigeration is unavailable.
- ☐ The packaging is intact and the food has been stored as instructed.
No-cook meal gap = total meal portions required – usable no-cook meal portions held
If the answer is below zero, record the gap as zero. Keep any surplus visible rather than using a negative result.
No-cook coverage percentage = usable no-cook meal portions held ÷ total meal portions required × 100
Calculate the percentage only when total meal portions required is greater than zero.
| No-cook check | Your result |
|---|---|
| Total meal portions required | T = ________ |
| Usable no-cook meal portions held | N = ________ |
| No-cook meal gap | T – N = ________ |
| No-cook coverage | N ÷ T × 100 = ________% |
In the worked example, suppose the household has 30 suitable no-cook meal portions for its 36 meal slots. The gap is 36 – 30 = 6 meal portions. Coverage is 30 ÷ 36 × 100 = 83.3%, which can be rounded to 83% for planning. UK Prepared recommends aiming for 100% no-cook coverage across the chosen core period, even if safe cooking is normally available.
What can be counted in the core total?
| Food source | Count as dependable no-cook food? | Reason |
|---|---|---|
| Unopened shelf-stable food that is safe to eat cold | Yes | Count realistic portions after checking the label and pack size. |
| Food that needs boiling, baking or frying | No | Count separately only if a safe and dependable cooking method is planned. |
| Food requiring substantial preparation water | Usually no | It transfers the shortage to the water supply. |
| Food in the fridge | No | Use early during an outage, but do not treat it as guaranteed multi-day stock. |
| Food in the freezer | No | It may stay frozen temporarily, but duration varies and some food still needs cooking. |
| Opened packs requiring refrigeration | No | Leftovers may not remain safe after the meal. |
| Food unsuitable for a household member | No | Allergy, medical, sensory, chewing or swallowing needs still apply during disruption. |
Keep fridge and freezer doors closed during a power cut. The Food Standards Agency power cut guidance says a closed fridge should stay cold for up to four hours. Food in a full freezer may stay frozen for up to 48 hours, or 24 hours if it is half full. These are estimates affected by the appliance, room temperature and door opening.
Step 3: build complete meals
Turn the calculated total into a menu before counting packs. A complete meal means a combination that would genuinely replace breakfast, lunch or an evening meal for the intended person. Do not count each component as a separate meal.
| Meal combination | Adult portions | Child portions | Times planned | Total meal portions |
|---|---|---|---|---|
| ________________________ | ______ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ | ______ |
| Total planned meal portions | ______ | ______ | ______ |
- ☐ Include familiar sources of carbohydrate, protein, fruit or vegetables and useful energy across the plan.
- ☐ Make every day workable without assuming that electricity, gas, tap water or refrigeration will remain available.
- ☐ Include drinks for preference or nutrition separately from the household drinking-water supply.
- ☐ Check salt, sugar, fibre and any condition-specific restrictions across the whole menu.
- ☐ Test one example day using the planned portions. If it would be obviously inadequate or impractical in ordinary life, revise it.
- ☐ Choose pack sizes that limit waste once opened.
The NHS Eatwell Guide assesses balance across a day or week rather than requiring every meal to match the same pattern. It also makes clear that individual energy needs vary and that people with special dietary or medical needs may require advice from a registered dietitian.
Step 4: convert portions into packs
Calculate each meal component separately. Use the number of portions your household actually obtains from the pack, not automatically the serving count printed on the front.
Packs required = portions of the component needed ÷ realistic portions per pack
Round every pack result up to the next whole pack. For example, if 12 breakfast portions need cereal and one pack provides eight realistic household servings, 12 ÷ 8 = 1.5, so two packs are required. Calculate milk, fruit or other components separately.
| Food or meal component | Portions needed | Portions per pack | Packs required | |
|---|---|---|---|---|
| ________________________ | ______ | ______ | ______ | |
| ________________________ | ______ | ______ | ______ | |
| ________________________ | ______ | ______ | ______ | |
| ________________________ | ______ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ | |
| ________________________ | ______ | ______ | ______ |
| Food or component | Packs required | Usable packs held | Packs to add |
|---|---|---|---|
| ________________________ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ |
| ________________________ | ______ | ______ | ______ |
Ordinary shelf-stable food that the household already eats is usually easier to rotate than specialist emergency rations. The UK Prepared emergency food storage guide provides practical meal ideas, storage checks and rotation guidance without requiring a commercial food kit.
Calculate infant, medical and pet supplies separately
Use the person’s existing clinical, feeding or care plan. Do not convert prescribed nutrition, infant feeds or specialist products into generic meal portions.
| Separate need | Normal daily requirement | Days | Total and source of instructions |
|---|---|---|---|
| Infant feeds or baby food | ________________ | ______ | ________________________ |
| Prescribed feeds or supplements | ________________ | ______ | ________________________ |
| Medical or texture-modified diet | ________________ | ______ | ________________________ |
| Allergy-safe separate food | ________________ | ______ | ________________________ |
| Pet or assistance-animal food | ________________ | ______ | ________________________ |
| Other specialist need | ________________ | ______ | ________________________ |
- ☐ Follow the normal care plan, clinician, dietitian, pharmacist, veterinary or manufacturer instructions as applicable.
- ☐ Keep known-safe allergy products in their original packaging so labels remain available.
- ☐ Recheck ingredients when replacing stock because product recipes can change.
- ☐ Include any preparation water, sterilising method, feeding equipment and safe-cleaning supplies.
- ☐ Test whether the intended person or carer can open and prepare every item without normal utilities.
- ☐ Extend the planning period where a specialist product is difficult to replace quickly.
Powdered infant formula requires safe preparation with freshly boiled water and sterilised equipment. If water cannot be boiled, UK emergency guidance recommends ready-to-feed formula. Follow the NHS formula-preparation instructions and any incident-specific public-health advice.
Final result card
| Result | Your figure |
|---|---|
| People in general meal calculation | ________ |
| Planning period | ________ days |
| Person-days | ________ |
| Total meal portions required | ________ |
| Total snack portions required | ________ |
| Usable no-cook meal portions held | ________ |
| No-cook meal gap | ________ |
| No-cook coverage | ________% |
| Specialist supplies calculated separately | Yes / No / Not applicable |
| Water for drinking and food preparation calculated | Yes / No |
| Next stock review | ________________ |
- ☐ Check use-by dates, best-before dates, pack damage and storage instructions.
- ☐ Put food with the earliest suitable rotation date at the front.
- ☐ Move food approaching its planned rotation date into ordinary meals and replace it during a normal shop.
- ☐ Keep a manual tin opener with food that requires one.
- ☐ Keep the food dry, away from household chemicals and protected from pests.
- ☐ Store heavy containers on stable shelving at a safe lifting height.
- ☐ UK Prepared recommends reviewing the calculation and stock every six months, after use and whenever household needs change.
Using the food during an outage
The UK Chief Medical Officers advise taking stock of food for everyone in the household, planning for several days and eating food in an order that reduces safety risks and waste.
- Use chilled food that is still safe first.
- Use safely defrosted frozen food that does not require cooking.
- Use shorter-life room-temperature food.
- Keep longer-life tinned, bottled and dried food until later.
Follow the current food-safety guidance for the incident. Never use a camping stove or barbecue indoors because carbon monoxide can kill. Do not rely on smell or appearance where official guidance says food should be discarded.
Emergency food resources and official guidance
- GOV.UK Prepare household guidance covers non-perishable food, drinking water, infant formula, pet food and other emergency supplies.
- GOV.UK Prepare power cut guidance explains no-cook food preparation, fridge protection and infant-feeding considerations during an outage.
- UK Chief Medical Officers’ food and nutrition advice explains how households should take stock, prioritise food and reduce health risks during a prolonged outage.
- Food Standards Agency power cut advice covers fridge and freezer temperatures, safer food use and infant formula in England, Wales and Northern Ireland.
- Food Standards Scotland power cut advice provides the corresponding guidance for Scottish households.
- NHS Eatwell Guide explains overall dietary balance, variation in energy needs and when specialist dietary advice may be needed.
- NHS guidance on making up baby formula explains water temperature, sterilisation, preparation and bottled-water limitations.
