Canning Altitude Adjustment Calculator
Enter your elevation and the tested recipe values to see the USDA-style time or pressure adjustment for boiling-water, dial-gauge pressure, or weighted-gauge pressure canning.
Adjusted processing time30
- Adjusted processing time (minutes)
- 30
- Adjusted canner pressure (psi)
- Not applicable
- Adjustment applied
- 10 minutes added for the 3,001-6,000 ft boiling-water band.
- Method instruction
- Boiling-water canning changes processing time, not pressure; keep the tested recipe food, pack style, jar size, and preparation method.
Use only with a current tested recipe from USDA, NCHFP, or a university Cooperative Extension source.
If that recipe supplies its own altitude table, follow the recipe table instead of this generic adjustment.
How to use this calculator
- Choose the canner method named by the tested recipe.
- Enter the altitude where the canner will run.
- Enter the recipe processing time for the exact food, pack style, jar size, and preparation method.
- For pressure canning, enter the base pressure listed for the lowest altitude band.
- Use the result only if the recipe does not already provide its own altitude table.
How altitude changes the canning process
Water boils at a lower temperature as elevation rises. In boiling-water canning, USDA guidance compensates by adding processing time above 1,000 feet. In pressure canning, the processing time normally stays the same and the canner pressure changes instead. Dial-gauge and weighted-gauge canners use different altitude bands, so the method matters.
This calculator encodes the published band logic. It does not interpolate between bands, because the tables are written as ranges. Exact endpoints stay in the lower band, and the next adjustment starts one foot above the endpoint.
The formula
Let A be altitude in feet, T0 be the tested recipe processing time in minutes, and P0 be the tested base pressure in pounds per square inch.
For boiling-water canning, T = T0 + ΔT. The added time is 0 minutes for 0-1,000 feet, 5 minutes for 1,001-3,000 feet, 10 minutes for 3,001-6,000 feet, 15 minutes for 6,001-8,000 feet, and 20 minutes for 8,001-10,000 feet. Pressure is not changed.
For dial-gauge pressure canning, T = T0 and P = P0 + max(0, ceil((A - 2,000) / 2,000)). That means the base pressure holds through 2,000 feet, then rises by 1 psi for each started 2,000-foot band.
For weighted-gauge pressure canning, T = T0. The pressure is P0 through 1,000 feet and P0 + 5 above 1,000 feet.
What moves the result
The altitude band is the main driver. A boiling-water recipe at 3,000 feet gets the 1,001-3,000 foot adjustment, while the same recipe at 3,001 feet moves to the next time band. A dial-gauge pressure recipe at 2,000 feet keeps its base pressure, while 2,001 feet adds 1 psi. Weighted-gauge pressure canning has only two generic bands: at or below 1,000 feet, and above 1,000 feet.
What this calculator leaves out
This calculator does not decide whether a food is safe for boiling-water canning or must be pressure canned. It does not check recipe acidity, jar size substitutions, pack style changes, venting procedure, gauge testing, canner manufacturer instructions, or whether a weighted gauge supports the pressure shown. It also stops at 10,000 feet; above that, use local Cooperative Extension guidance instead of extrapolating.
Worked example
Suppose a tested boiling-water recipe gives a 25 minute process at 0-1,000 feet, and the canner will run at 2,500 feet. The 1,001-3,000 foot band adds 5 minutes, so the adjusted processing time is 30 minutes.
For a dial-gauge pressure recipe with a 10 minute process and a 6 psi base pressure, 2,500 feet falls in the 2,001-4,000 foot band. The calculator adds 1 psi and keeps the 10 minute time, giving 7 psi for 10 minutes. For a weighted-gauge canner with a 5 psi base pressure at the same altitude, the result is 10 psi for the tested time.
Common questions
Why does altitude change canning time or pressure?
At higher elevations, water boils at a lower temperature. Boiling-water canning compensates by adding time, while pressure canning compensates by using the pressure specified for the elevation band. The goal is to follow the tested process conditions, not to estimate a new recipe.
Do I increase time or pressure when pressure canning?
For pressure canning, keep the tested processing time and adjust pressure for the canner type and altitude band. Dial-gauge canners use several pressure bands, while weighted-gauge canners generally move to the higher weight above 1,000 feet. Do not increase both time and pressure unless the tested recipe specifically says to.
What is the difference between dial-gauge and weighted-gauge adjustments?
A dial gauge displays pressure continuously, so USDA tables can step up by 1 psi across elevation bands. A weighted gauge controls pressure by fixed weights, so the generic table uses the base weight through 1,000 feet and the higher weight above that. Always use the table that matches your canner.
How do I find my home elevation?
Use the elevation for the place where the canner is operating. A local Cooperative Extension office, local government GIS map, USGS map, or GPS/elevation tool can help. If your estimate is near a band boundary, use the higher band unless you can confirm the elevation is within the lower band.
Can altitude adjustments make an untested recipe safe?
No. Altitude adjustment only modifies a tested process for local elevation. It does not validate a changed recipe, an untested food mixture, a larger jar, a different pack style, or a food that needs a different canning method.
What happens when my elevation is exactly on a band boundary?
Exact endpoints remain in the lower band. For example, 3,000 feet is still in the 1,001-3,000 foot boiling-water band, while 3,001 feet moves to the next band. The same endpoint rule applies to the pressure-canner bands.