Canning Time Altitude Calculator
Adjust water-bath canning processing time for altitude. Higher elevations require longer processing because water boils at a lower temperature.
Adjusted Processing Time
12 min
How to Adjust Canning Time for Altitude
Rule
For water-bath canning above 1,000 feet:
Water boils at a lower temperature at higher elevations (roughly 1.84°F less per 1,000 ft). The longer processing compensates for the reduced heat transfer.
Important
This applies to water-bath canning only. For pressure canning, increase the pressure (not the time) at altitude. Always follow USDA-tested recipes.
Example Calculation
A jam recipe calling for 10 minutes processing at 3,000 feet altitude.
- 01Base time = 10 min (under 20, so add 1 min per 1,000 ft above 1,000)
- 02Extra = ceil((3000 - 1000) / 1000) x 1 = 2 minutes
- 03Adjusted time = 10 + 2 = 12 minutes
- 04Boiling point at 3,000 ft = 212 - 5.5 = 206.5°F
Frequently Asked Questions
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