Water Bath Canning Altitude Adjustment Calculator
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Use the processing time from a tested recipe, such as USDA, NCHFP, or a trusted extension service.
Your base processing time is 10 minutes or more, so the processing itself sterilizes the jars. Wash jars in hot soapy water and keep them hot until filling.
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FAQ
Why do I need to adjust processing time for altitude?
Water boils at a lower temperature as altitude increases, so food needs more time in the canner to reach a safe internal temperature. Skipping this adjustment can leave food under-processed.
Can I use this calculator for pressure canning?
No. This calculator is for boiling water bath canning only. Pressure canning uses pressure adjustments instead of time adjustments, and the amounts are different.
Where do I find the base processing time for my recipe?
Use the processing time listed in a tested recipe from a source like USDA, NCHFP, or a trusted extension service. Do not guess or estimate this number.
What happens if I don't know my exact altitude?
Round up to the next altitude range rather than down. It is safer to over adjust processing time than to under adjust it.
Can I reduce processing time if I live at a lower altitude than a recipe assumes?
No. Never reduce processing time below what a tested recipe specifies, regardless of altitude.