Altitude adjustments for safe home canning
Water boils at a lower temperature the higher you live, so a jar processed for the sea-level time may not get hot enough for long enough. This canning altitude adjustment calculator gives you the tested answer for your elevation: the longer boiling-water (water-bath) time, or the higher pressure for a dial-gauge or weighted-gauge pressure canner. Pick the food, the pack style and jar size, and type your altitude in feet or metres.
Every number comes from the USDA Complete Guide to Home Canning (2015 revision), published by the National Center for Home Food Preservation (NCHFP), read on 24 October 2026. Nothing is extrapolated or invented: the tool looks up the row and altitude column the Guide prints for that food, and shows the whole altitude chart so you can check it against your copy.
How to use the Canning Altitude Adjustment Calculator
- Choose your canner: boiling-water, dial-gauge pressure or weighted-gauge pressure.
- Choose the food. Low-acid foods such as green beans, corn, meat and stock are listed for pressure canners only.
- Choose the pack style and jar size exactly as in the recipe (hot or raw pack; half-pints and pints share times, as do 1½-pints and quarts).
- Enter your altitude. Read the time or pressure, and use the chart below to see the other altitude bands.
- For a pressure recipe of your own from a tested source, choose “My tested pressure-canning recipe”, enter its sea-level pressure and time, and read the adjusted pressure.
Canning Altitude Adjustment Calculator features
Tested data only
25 foods from the USDA Guide’s fruit, tomato, vegetable, meat, pickle and jam chapters, each with its source chapter.
Three canner types
Boiling-water times, dial-gauge pressures in four bands up to 8,000 ft, and weighted-gauge pressures.
Safety guards
Low-acid foods are refused in a water bath, and options the Guide marks “not recommended” are shown as such.
Acid reminder
Tomato products show the bottled lemon juice or citric acid the Guide requires.
How altitude changes a canning process
In a boiling-water canner the jars can never get hotter than boiling water, about 212 °F (100 °C) at sea level and roughly 203 °F (95 °C) at 5,000 ft (see the boiling point at altitude calculator). The Guide compensates with longer times. Each product has its own altitude columns: many fruit and tomato tables use 0–1,000, 1,001–3,000, 3,001–6,000 and above 6,000 ft, while pickles, salsa and jams use 0–1,000, 1,001–6,000 and above 6,000 ft. That is why there is no single “add five minutes” rule here.
In a pressure canner the time stays the same and the pressure goes up. For a dial gauge the Guide uses 11 psi at 0–2,000 ft, 12 psi at 2,001–4,000 ft, 13 psi at 4,001–6,000 ft and 14 psi at 6,001–8,000 ft (6, 7, 8 and 9 psi for the low-pressure tomato options). A weighted gauge cannot be adjusted in small steps, so above 1,000 ft it is used at 10 instead of 5 psi, or 15 instead of 10 psi.
Botulism and the limits of this tool
- Low-acid foods need a pressure canner. Spores of Clostridium botulinum survive boiling; only the 240 °F (116 °C) reached under pressure destroys them in a tested time.
- Follow the whole recipe. Altitude is one variable. Jar size, headspace, pack style, acidification, venting for 10 minutes and natural cooling all matter.
- Dial gauges drift. Have yours tested each year; replace it if it reads more than 2 psi off.
- Above 8,000 ft the Guide’s dial-gauge tables end. Ask your county Extension office before canning at higher elevations.
- Changed recipes are untested. Adding thickeners, extra vegetables or less acid can make a tested time unsafe.
Where the numbers come from
The USDA Complete Guide to Home Canning, 2015 revision, is free from the National Center for Home Food Preservation (nchfp.uga.edu) as eight PDFs. The canner rules are in Guide 1; the product tables are in Guides 2 to 7. The weighted-gauge rule and dial-gauge altitude bands above are taken directly from those tables. For jam sugar ratios see the jam sugar ratio calculator, and for brines the brine calculator.
Canning Altitude Adjustment Calculator FAQ
How do I adjust canning time for altitude?
For a boiling-water canner, use the longer time printed in your tested recipe’s altitude column; it varies by food. For a pressure canner, keep the time and raise the pressure: dial gauge 11, 12, 13 or 14 psi in 2,000-ft steps up to 8,000 ft; weighted gauge 15 psi above 1,000 ft for a 10 psi recipe.
What pressure should I use for pressure canning at 5,000 feet?
13 psi on a dial gauge, or 15 psi on a weighted gauge, for low-acid foods processed at 11 or 10 psi at sea level. The process time does not change.
Can I water-bath can green beans or meat at any altitude?
No. They are low-acid foods and the USDA Guide gives only pressure-canner processes for them, because boiling water cannot destroy botulism spores.
Do I need to adjust under 1,000 feet?
No. The sea-level times and pressures in the USDA Guide apply from 0 to 1,000 ft (to 2,000 ft for dial-gauge pressures).
Why is the 15 psi weighted option “not recommended” for tomatoes above 1,000 ft?
Above 1,000 ft a weighted gauge has to go up a step, and the Guide does not recommend more than 15 psi with home pressure canners, so the 15 psi tomato option has no high-altitude version. Use the 5 or 10 psi option instead.
Is this a substitute for the recipe?
No. It is information only. Follow the complete tested recipe from the USDA Guide or NCHFP, including preparation, headspace and cooling.