Altitude: find yours first, because it changes the rest
Sources last opened 2026-08-26.
The short version
Find your elevation before you look at any schedule. Above 1,000 feet, a sea-level process time is not adequate, because water boils cooler the higher you are and a lower boiling temperature is less effective at killing bacteria [F-4.1].
It is a one-off job. Look it up once, write it inside a cupboard door, and every tested table you ever read becomes usable in about four seconds.
One thing worth knowing before you go looking: the USDA guide deliberately does not publish a list of elevations, and it says why [F-4.5]. NCHFP runs a "Find Your Elevation" page instead, linked below.
Do this before anything else
Every tested canning schedule in the United States is written in altitude bands. Until you know which band you are in, a process time is not a number you can use — it is a number for somebody else's kitchen.
So: find your elevation, once. NCHFP publishes a page for exactly this, linked above. A phone's compass or maps app will usually give you a figure too. Write it somewhere you will find it again, because you will want it every time you open a new recipe.
Then, when you read a table, you are not looking for "the time". You are looking for the intersection of your food, your jar size and your band.
What is actually happening up there
Boiling is not a fixed temperature. Water boils when its vapour pressure equals the pressure of the air pushing down on it, and there is less air pushing down the higher you go. So the boiling point falls with elevation, and a pot at a furious rolling boil at altitude is genuinely cooler than the same pot at sea level.
The guide states the consequence directly: lower boiling temperatures are less effective for killing bacteria, and increasing the process time or the canner pressure compensates [F-4.1].
Notice which lever each canner gets. A boiling water canner cannot be made hotter, so the only available compensation is time. A pressure canner can be made hotter, so its tables adjust the pressure instead and leave the time alone. Both are the same correction, applied where it can be applied.
The threshold in the guide is 1,000 feet or more [F-4.1]. That is lower than most people expect, and it puts a large part of the country inside the adjustment.
The bands are not the same on every table
This is the part that trips up careful readers, because it looks like a detail and behaves like a trap.
Boiling-water tables use 0–1,000 ft, 1,001–3,000 ft, 3,001–6,000 ft and an open-ended top band above 6,000 ft [F-4.2]. Weighted-gauge tables use two bands: 0–1,000 ft, and above 1,000 ft [F-4.2]. Dial-gauge tables use four: 0–2,000 ft, 2,001–4,000 ft, 4,001–6,000 ft, 6,001–8,000 ft [F-4.2].
Take a reader at 2,500 feet. On a boiling-water table they are in the second band. On a weighted gauge they are simply "above 1,000 ft" [F-4.2]. On a dial gauge they are in the second of four. Three different rows, one kitchen, and none of them is a mistake — the tables are built differently because the machines correct differently.
The practical habit is to read the column headings every time rather than remembering "my band". It takes a second and it removes the error entirely.
Where the dial-gauge tables stop
The dial-gauge columns end at 6,001–8,000 ft, and there is nothing beyond that in the guide [F-4.2]. The boiling-water and weighted-gauge tables do not have this problem, because their top bands are open-ended.
So the accurate sentence is narrow: above 8,000 feet a dial-gauge canner has no USDA process, and a weighted gauge does [F-4.2]. It is worth being this careful, because the loose version — "the tables stop at 8,000 feet" — is repeated widely and is not true of all three table types.
Numbers for higher elevations do circulate, including on a well-known manufacturer's chart. They are not USDA figures, they trace back to a different publication, and that trail is worth following before you rely on them [F-4.4]. It is followed on above 8,000 feet, where the tables stop [F-4.2].
A note on why the refusal to publish a lookup is a good sign
It would have been easy for a federal guide to print a county table. Somebody would have used it, it would have been wrong for the reader on the ridge above town, and nobody would ever have known which readers it failed.
Instead the guide names the problem — wide variation within a state and even a county, Kansas from 75 ft to 4,039 ft, Colorado between 3,000 and 10,000 ft — and declines [F-4.5].
That is the standard I would like to hold every canning page to, including this one. Publish what you can stand behind, name the source, and where the answer depends on something only the reader can supply, say so and tell them where to get it.
What altitude actually changes
Using the process time for canning food at sea level may result in spoilage if you live at altitudes of 1,000 feet or more. Water boils at lower temperatures as altitude increases. Lower boiling temperatures are less effective for killing bacteria. Increasing the process time or canner pressure compensates for lower boiling temperatures.
USDA Complete Guide to Home Canning, 2015 revision, p. 1-10
The link above opens the document itself, so a printed page number leads somewhere. What this document is, and who maintains it.
Opened and read by this site on 2026-08-26.
Four sentences, and each one is a separate fact [F-4.1].
There is a threshold, and it is 1,000 feet. Below it, published sea-level times apply as written.
There is a mechanism. Boiling is not a temperature, it is a pressure event: water boils when its vapour pressure matches the air pressure above it. Less air above you means boiling happens cooler. A pot on a rolling boil in Denver is genuinely cooler than a pot on a rolling boil in Miami, and no amount of extra heat under it changes that.
There is a consequence. Cooler water is less effective at killing bacteria, so the same time at the same visible boil delivers less than it did at sea level.
And there is a remedy, in two forms. In a boiling water canner you cannot raise the temperature, so the tables raise the time. In a pressure canner you can raise the temperature, so the tables raise the pressure instead. Same problem, two solutions, and which one applies to you depends on which table you are reading.
Why the guide will not simply give you a list
It is not practical to include a list of altitudes in this guide, since there is wide variation within a State and even a county. For example, the State of Kansas has areas with altitudes varying between 75 ft to 4,039 ft above sea level… Colorado, on the other hand, has people living in areas between 3,000 and 10,000 ft above sea level… To list altitudes for specific counties may actually be misleading, due to the differences in geographic terrain within a county.
USDA Complete Guide to Home Canning, 2015 revision, p. iv
The link above opens the document itself, so a printed page number leads somewhere. What this document is, and who maintains it.
Opened and read by this site on 2026-08-26.
A federal document declining to print a table it could easily have printed, and giving its reasoning [F-4.5].
The reasoning is sound and checkable. Kansas, a state most people think of as flat, spans 75 ft to 4,039 ft. Colorado has residents between 3,000 and 10,000 ft. A county-level list would give one number to people living hundreds of feet apart, and a number that confident would be worse than no number, because a reader would use it without checking.
Note what this is not. It is not the guide being unhelpful, and it is not a gap in the research. It is a document refusing to publish something it cannot stand behind at the precision the use requires.
I find this the most reassuring paragraph in the guide. A source that declines to guess in one place is a source you can lean on in the places where it does give you a number — and it is a standard almost nothing else in this subject is held to.
The bands are not the same on every kind of table, and this is where people go wrong
0–2,000 ft | 2,001–4,000 ft | 4,001–6,000 ft | 6,001–8,000 ft
The link above opens the document itself, so a printed page number leads somewhere. What this document is, and who maintains it.
Opened and read by this site on 2026-08-26.
Those are the four altitude column headings carried by every dial-gauge process table in the guide, reproduced here without any of the times or pressures under them. There is no fifth column [F-4.2].
The other two kinds of table are banded differently. Boiling-water tables run 0–1,000 ft, 1,001–3,000 ft, 3,001–6,000 ft, and then an open-ended "Above 6,000 ft" [F-4.2]. Weighted-gauge tables have two columns: 0–1,000 ft and "Above 1,000 ft" [F-4.2].
Two things follow. First, "my altitude adjustment" is not one thing you learn once — the band you fall into depends on which type of table you are reading, and the boundaries genuinely differ. Second, the open-ended top bands on the boiling-water and weighted-gauge tables cover any elevation, however high, while the dial-gauge columns stop.
Say that last point precisely, because it is usually said too broadly: above 8,000 feet a dial-gauge canner has no USDA process, and a weighted gauge does [F-4.2]. The guide contains no dial-gauge column beyond 6,001–8,000 ft. Figures for higher elevations do circulate, they come from somewhere other than USDA, and where they come from is a story with a page of its own: above 8,000 feet, where the tables stop.
What people ask next
My phone, the town sign and a website all give different elevations.
Take the one that describes where your kitchen is, not where the town centre is, and if they straddle a band boundary, use the higher band. This is a judgement rather than a rule from the guide: more heat than the recipe requires costs texture, and less heat than it requires costs the process. The guide's own warning is that county-level figures can mislead precisely because terrain varies within a county [F-4.5].
Does altitude matter for water bath canning, or only pressure?
Both. Water boils cooler as you go up regardless of what the pot is called, and boiling-water tables carry altitude columns for exactly that reason [F-4.2]. In a boiling water canner the adjustment is extra time; in a pressure canner it is extra pressure [F-4.1].
I live at 400 feet. Can I ignore all of this?
Use the sea-level column, and still know your number. The threshold in the guide is 1,000 feet or more [F-4.1], so below that the published sea-level times apply as written. Knowing your figure still matters the first time you follow a recipe from somebody who lives somewhere else.
Why does a weighted gauge only have two bands?
Because it cannot be set to an in-between figure. A weighted gauge regulates at fixed steps, so the guidance moves you up a whole step above 1,000 feet rather than fine-tuning [F-3.4]. A dial gauge reads continuously, which is why its tables can afford narrower bands — and why it has to be checked for accuracy every year [F-3.5].
What if I am above 8,000 feet with a dial gauge?
Then the USDA tables have no column for you [F-4.2], and the honest answer is that the tested guidance runs out at that point rather than that some other number is fine. A weighted gauge does have an open band that covers you [F-4.2]. Your state Extension service is the right place to ask, and several of the high-elevation states publish their own guidance.
Read these yourself
NCHFP — Find your elevation
nchfp.uga.edu
USDA Complete Guide to Home Canning, 2015 revision
nchfp.uga.edu
NCHFP — General canning information
nchfp.uga.edu