Canning Calculator
Find out how many jars you need for any amount of produce.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
Can't find what you need?
Request a ToolHow to Use the Canning Calculator
This calculator tells you how many canning jars to prepare for your harvest or bulk produce purchase. Here is how to use it:
- Select your produce. Each produce type has a different yield ratio because density, water content, and packing method all affect how much fits in a jar. The yields shown are averages from USDA canning guidelines.
- Enter the pounds of produce. Weigh your produce before washing and trimming. The yield ratios account for typical prep waste like peach skins, tomato cores, and bean stems.
- Choose your jar size. Quart jars are best for tomatoes and large quantities. Pint jars are the most versatile. Half-pint jars are ideal for jam, jelly, and small-batch pickles.
Results round up so you always have enough jars on hand. Have 10-15% extra jars available in case of breakage or slight over-yield. Use Share to send your jar count to a canning partner.
About the Canning Calculator
The yield ratios in this calculator come from USDA Complete Guide to Home Canning standards, which are the most widely referenced source for safe home canning. Tomatoes at 2.5 lbs per quart, peaches at 2 lbs per quart, green beans and pickles at 1.5 lbs per quart, and jam at 1 lb per pint are all consistent with those guidelines for whole or crushed pack methods.
Note that these are averages. Actual yield varies by variety, ripeness, and how tightly you pack the jars. Small tomatoes pack tighter than large ones. Peaches in heavy syrup pack differently than water-packed. For precise canning always follow a tested recipe from USDA, Ball, or the National Center for Home Food Preservation rather than scaling by weight alone. All calculations run in your browser with no data stored or transmitted.
Frequently Asked Questions
How many pounds of tomatoes do I need to fill 7 quart jars?
To fill 7 quart jars with whole or crushed tomatoes, you need approximately 17-18 lbs of fresh tomatoes (using the 2.5 lbs per quart average). This is a standard canning batch size. For diced or sauce-style tomatoes, the yield is lower because more tomato mass fits when the pieces are cut smaller. Always have a few extra pounds on hand in case some tomatoes are overripe or damaged.
Can I use any jar size for any produce?
Generally yes, but your tested canning recipe specifies a jar size for a reason. Processing times are calibrated to jar size because heat penetration differs between jar volumes. Switching from pint to quart jars without adjusting processing time can result in under-processed food. Always follow your tested recipe's jar size and processing time. That said, many recipes have tested versions for both pints and quarts with different processing times listed.
Do I need to sterilize my canning jars?
For high-acid foods processed in a water bath canner for 10 minutes or more, pre-sterilization is not necessary because the processing time sterilizes the jars. For recipes with less than 10 minutes of processing time, jars must be pre-sterilized. For all canning, jars should be clean and hot (run them through the dishwasher or keep them in hot water) to prevent thermal shock when filled. Lids should never be pre-boiled: just simmer them in warm water to soften the seal compound.
How long does home-canned produce last?
Properly sealed and processed home-canned produce is best used within 12-18 months for peak quality, though it remains safe to eat for much longer if the seal is intact and there are no signs of spoilage. Store jars in a cool, dark, dry place. After opening, refrigerate and use within a week. Always discard jars with bulging lids, spurting liquid when opened, off smells, or any visible mold. When in doubt, throw it out.