A thriving home vegetable garden at golden hour, with rows of leafy greens, climbing beans and a cottage in the distance
Free · No Account Needed · 55 Crops · 8 Climate Zones

Know your numbers.
Grow with peace of mind.

The supermarket has always been there -- until it isn't. This tool works out exactly what that gap looks like for your household: in seeds, in rows, in kilograms per year.

Start the calculator → How it works
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About This Tool

Know Exactly What You Need, Before You Need It

Food When The Shops Stop turns vague self-sufficiency dreams into hard numbers -- how many seeds, how many rows, how many kilograms per person per year. No guesswork, no rounding up.

55
Crops Modelled
Yield, storage life and calorie density calculated for every crop that matters, zone by zone.
8
Climate Zones
From tropical to alpine -- your zone changes what's viable and how much you'll get.
26
Livestock & Wild Sources
Feed costs subtracted honestly, so net calories are net calories.
Real
Loss Rates Included
Germination failures, pests and wind losses are built in -- not left for you to discover.
A gardener holding a freshly harvested basket of carrots, beetroot, kale and tomatoes in a home vegetable garden

Most Of Us Have Never Had To Think About This

The supermarket has always been there. But supply chains are more fragile than they look, and the gap between what most people could grow and what they would actually need is larger than almost anyone realises.

Real growing means real soil, real weather, and real work -- not a spreadsheet guess. This tool starts from what's actually achievable on the ground.

More About How It Works →

How it works -- 7 steps

Overhead view of freshly harvested carrots, potatoes and leafy greens on a wooden table beside a hand-drawn garden plan
1
Climate Zone
Pick your growing zone -- from tropical to alpine. This filters which crops are viable and adjusts yields and storage durations.
2
Your Group
Count your adults, teenagers and children. The calculator scales calorie needs by age and gender.
3
Activity Level
Growing food is physical work. The tool warns you if your stated activity level will underestimate real-world calorie burn.
4
Food Sources
Add kept livestock, wild-caught food and other sources. Feed costs are subtracted from your crop plan honestly.
5
Crop Selection
Choose which crops you want to grow. Only crops viable in your zone are shown, with yield, storage and loss data pre-loaded.
6
Calorie Split
Decide what percentage of calories each crop provides. Set a surplus buffer against bad years.
7
Your Plan
See exactly how many seeds to buy, how much land you need, and your weeks of food security. Print and save your plan.
Ready to begin? Start the calculator →

8 Climate Zones, Modelled Properly

Yields, storage life and viable crops all shift with your zone. Pick the one that matches where you grow.

All Climate Zones →
Lush tropical vegetable garden with banana leaves and cassava in a humid jungle-edge setting
Tropical / Humid
Year-round growing, 2-3 harvests
 Subtropical smallholding with citrus trees and vegetable rows in warm hazy sunlight
Subtropical
9-11 month growing season
 Mediterranean terraced vegetable garden with olive trees and dry golden hills
Mediterranean
Dry hot summers, mild winters
 Damp green vegetable allotment with raised beds under an overcast British-style sky
Temperate Maritime
Mild, wet, frost risk Oct-Apr
 Midwest-style vegetable farm rows under a big open sky with autumn colour
Temperate Continental
Hot summers, cold winters
 Short-season northern vegetable garden with hardy greens near a spruce forest edge
Cool / Boreal
Short, intense summer only
 Drought-hardy vegetable garden with drip irrigation in a dusty desert-fringe landscape
Arid / Semi-Arid
Water is the primary constraint
 High-altitude terraced vegetable plot with misty mountain slopes in the background
Highland / Alpine
Cool, often wet year-round

Ready to know your numbers? Get your personalised seed plan in under 10 minutes.

Start the calculator →

What this tool is -- and isn't

This calculator gives you a realistic starting point, not a guarantee. Real growing involves weather, pests, disease, soil condition, water availability, and years of accumulated skill. The numbers here use honest loss rates -- germination failures, pest damage and wind losses are all accounted for -- but no calculator replaces experience.

Use this as a map, not a contract. The most valuable thing it can do is show you the scale of what's needed -- because most people who've never grown food seriously underestimate it by a factor of ten.

Frequently Asked Questions

How many seeds do I need to grow to feed my family?

It depends on your group size, climate zone, which crops you choose and how much of your calories come from other sources. The Food When The Shops Stop calculator works this out precisely, accounting for germination failures and pest losses in your zone.

Is the calculator free to use?

Yes -- completely free, no account required and no paywall. Just answer 7 questions and download your printable seed plan.

Does it work for my climate zone?

The calculator covers 8 climate zones from Tropical to Alpine, including Temperate Maritime (UK, Ireland, NW Europe), Mediterranean, Continental, Boreal, Arid and Highland.

Does it include livestock and wild food?

Yes -- you can add kept livestock with honest net calorie economics (feed costs subtracted), wild-caught animals with skill level adjustments, and other food sources.