Water Bath Canning Time Calculator
Water boils cooler at altitude, so boiling water bath canning needs extra time. Enter your recipe time at sea level and your elevation to get the minutes to add and the total processing time, based on the USDA chart.
How to adjust water bath canning time
- Enter the processing time your tested recipe gives for sea level, in minutes.
- Enter your elevation in feet.
- Read the minutes to add and the total processing time, then process for the full total.
Examples
10 minute recipe at 2500 ft
10 min base, 2500 ft
band 1001-3000, add 5 min, 15 min total
10 minute recipe at 7000 ft
10 min base, 7000 ft
band 6001-8000, add 15 min, 25 min total
Frequently asked questions
Why does altitude change canning time?
Water boils at a lower temperature as elevation rises, so the contents of the jar reach a lower peak temperature. To make up for that and ensure safety, the USDA chart adds processing time as altitude increases.
What are the USDA altitude bands?
For boiling water bath canning the common chart adds 0 minutes from 0 to 1000 feet, 5 minutes from 1001 to 3000, 10 minutes from 3001 to 6000, 15 minutes from 6001 to 8000, and 20 minutes from 8001 to 10000 feet.
Where do these numbers come from?
They follow the USDA Complete Guide to Home Canning and the National Center for Home Food Preservation, which publish altitude adjustment charts for boiling water bath processing. Always start from a current, tested recipe.
Does this work for pressure canning?
No. Pressure canning adjusts the pressure for altitude rather than the time, and it follows a different chart. This calculator is only for boiling water bath canning, which adjusts the processing time.
Is this a substitute for a tested recipe?
No. This is a food safety guideline that adjusts an already tested time. Use a current USDA or extension recipe for the food you are canning, follow its method, and apply the altitude adjustment on top of its sea level time.
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