Gardening & Food Calculators
Thirteen free calculators for growing, storing and preserving food on a homestead. They are organised below into two groups, so you can plan the garden first and then plan what happens to the harvest.
Canning & Preserving Altitude Calculator
Adjust boiling-water processing time or pressure canner PSI for your elevation — using USDA/National Center for Home Food Preservation figures.
Cider Press Yield Calculator
Estimate how many gallons of fresh cider you'll get from your apples, based on your press's typical efficiency.
Garden Yield & Space Calculator
Work out how many plants fit your garden space, or how much space you need to hit a harvest target.
Maple Syrup Sap-to-Syrup Yield Estimator
Turn your sap volume and sugar content (Brix) into an expected syrup yield — using the maple industry's own "Rule of 86," not a rough guess.
Maple Tree Tap Count Calculator
How many taps can your tree sustainably support? Based on trunk diameter guidelines from university maple extension programs.
Orchard Tree Spacing & Pollination Calculator
Minimum planting distance and pollination needs for 22 fruit and nut trees — not just the usual apple-and-pear shortlist.
Planting Date Calculator
Work out when to start seeds indoors and when it's safe to plant outside, based on your local frost dates.
Root Cellar Sizing & Storage Planner
Figure out how much storage space your harvest needs — and which crops need separate cold-and-moist vs. cool-and-dry zones.
Seed Saving Isolation Distance Calculator
Find the recommended isolation distance between varieties of the same crop, so the seeds you save grow true to type next year.
Worm Bin Size & Feed Calculator
Size a vermicomposting bin, and know how many worms to start with, from your household's weekly food scraps.
Raised Bed Soil Calculator
How much soil, in cubic feet, yards and bags, to fill your raised beds, with a mix recipe and a settling allowance.
Compost Carbon-to-Nitrogen Ratio Calculator
Estimate the carbon-to-nitrogen ratio and moisture of a compost pile from the materials you have.
Canning Yield Calculator: Produce per Jar
How many quart or pint jars a given weight of fresh produce will fill.
Plan the garden
Good garden planning starts with the calendar and the space. The planting date calculator works back from your frost dates to a sowing schedule, and the garden yield and space calculator estimates how much bed area you need for the amount of food you want. If you grow fruit, the orchard spacing and pollination calculator shows how far apart to plant trees and which varieties need a pollination partner. The seed saving isolation calculator gives the distance needed to keep varieties of the same species from crossing, and the worm bin calculator sizes a bin to the food scraps you actually produce. The raised bed soil calculator tells you how much soil to buy for beds of any shape, and the compost ratio calculator estimates the carbon-to-nitrogen ratio and moisture of a pile.
Preserve and store the harvest
Food preservation is where mistakes cost the most, so these tools lean on published guidance. The canning altitude calculator adjusts processing time or pressure for your elevation, because water boils at a lower temperature at altitude and under-processed jars are a safety risk. The root cellar planner sizes storage for the crops you plan to keep. Maple producers can use the tap count calculator to decide how many taps their trees and equipment can support, then the sap-to-syrup yield estimator to predict output from the sugar content of the sap. The cider press yield calculator estimates juice from a given weight of apples. The canning yield calculator estimates how many jars a given weight of produce will fill.
Why altitude and sugar content matter
Two of the most common homestead food questions have the same underlying answer: the number you were told is an average, and your situation is not average. A canning recipe written for sea level needs adjusting above about 1,000 feet. The old rule that 40 gallons of maple sap make one gallon of syrup assumes sap at about 2 percent sugar, and sap from your trees may be lower or higher. The calculators ask for altitude and sugar content because those inputs move the answer.
Safety first for canning
Low-acid foods such as vegetables, meat and most soups must be processed in a pressure canner. A boiling water bath is only safe for high-acid foods. Use tested recipes from your state extension service or the National Center for Home Food Preservation, and do not change ingredient amounts, jar sizes or processing times in a tested recipe. These calculators help you adjust for altitude. They do not replace a tested recipe. Read our safety disclaimer before relying on any food preservation number.
Where to start
If you are new to growing, begin with the planting date calculator, because timing is the single biggest factor in a first garden. If you already have a harvest coming in, start with the canning altitude calculator and the root cellar planner so the food you grew does not go to waste. For a season-by-season walkthrough, read the garden year guide, and for food safety read preserving the harvest safely.
Common questions
What if I do not know my frost dates?
Your local cooperative extension office or a county weather record can give the average last spring frost and first fall frost for your area. Those averages are probabilities, not promises, so plant tender crops a week or two after the average last frost date unless you can protect them.
Can I use the canning calculator instead of a tested recipe?
No. The calculator only adjusts for altitude. A tested recipe sets the ingredients, jar size, headspace and base processing time for safety, and none of those should be changed.