How much extra time do I add for canning at altitude?

For boiling-water-bath canning, add processing time by altitude bracket: 0 min at 0–1,000 ft, 5 min at 1,001–3,000 ft, 10 min at 3,001–6,000 ft, 15 min at 6,001–8,000 ft, and 20 min at 8,001–10,000 ft (USDA Complete Guide to Home Canning). Add the extra minutes to the recipe's sea-level time — never reduce it.

What PSI should I use for pressure canning at my altitude?

With a dial gauge: 11 psi to 2,000 ft, 12 psi to 4,000 ft, 13 psi to 6,000 ft, 14 psi to 8,000 ft, 15 psi to 10,000 ft. With a weighted gauge it is a step function: 10 lb up to 1,000 ft, then 15 lb above 1,000 ft. Processing time stays the same at any altitude for pressure canning; only the pressure changes.

Why does the weighted gauge jump from 10 to 15 pounds at 1,001 feet?

Weighted gauges only come in 5, 10 and 15 lb weights, so there is no 11–14 lb setting — the USDA table rounds up to the next available weight. That means as soon as you pass 1,000 ft you must use 15 lb, not 10. It is a common beginner trap, so this calculator flags it.

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Canning altitude calculator

Enter your altitude for the water-bath time to add and the pressure-canner PSI — straight from the USDA brackets, never rounded down.

Altitude changes canning because water boils cooler as you climb. For boiling-water-bath canning you compensate with more time; for pressure canning you compensate with more pressure (the time stays the same). This calculator returns both from the USDA Complete Guide to Home Canning tables. It only ever rounds up to the safe bracket — it is never more permissive than the printed tables.

Your altitude

Altitude (feet above sea level)

Pressure-canner gauge

Safety note. This adjusts a tested recipe for altitude — it does not make an untested recipe safe. Always start from a current USDA / NCHFP or So Easy to Preserve recipe, use the full processing time and pressure, and when in doubt, process longer or at higher pressure. Improperly canned low-acid foods can cause botulism, which can be fatal. This tool never shortens a process.

Canning a specific food?

This page handles altitude. Seal carries the whole safe-canning workflow: a citation-backed recipe library (which foods need pressure vs. water bath), acidity and headspace checks, jar-size and hot-vs-raw-pack rules, and altitude baked into every process spec — so you get one final "run it this long, at this pressure" answer per batch. Every recipe cites USDA / NCHFP.

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Altitude brackets (reference)

Boiling-water-bath — minutes to add

Altitude	Add to process time
0 – 1,000 ft	+0 min
1,001 – 3,000 ft	+5 min
3,001 – 6,000 ft	+10 min
6,001 – 8,000 ft	+15 min
8,001 – 10,000 ft	+20 min

Pressure canner — PSI by gauge

Altitude	Dial	Weighted
0 – 1,000 ft	11	10
1,001 – 2,000 ft	11	15
2,001 – 4,000 ft	12	15
4,001 – 6,000 ft	13	15
6,001 – 8,000 ft	14	15
8,001 – 10,000 ft	15	15

Pressure-canning time does not change with altitude — only the pressure does. Water-bath pressure can't change (it's atmospheric) — so time does.

FAQ

How much time do I add at altitude?
By bracket: +5 min from 1,001 ft, +10 from 3,001, +15 from 6,001, +20 from 8,001 ft — added to the recipe's sea-level water-bath time.

What PSI at my altitude?
Dial climbs 11→15 psi with altitude; weighted is a step: 10 lb to 1,000 ft, then 15 lb above. Use the calculator for your exact figure.

What if I'm above 10,000 ft?
The USDA tables stop at 10,000 ft. Above that, this calculator will not extrapolate — contact your NCHFP or local Extension office for guidance.

Sources

USDA Complete Guide to Home Canning, Part 1: Principles of Home Canning — altitude tables (via NCHFP)
SDSU Extension — Altitude adjustments for home canning

These are the published USDA brackets. This calculator never rounds down; when your altitude is near a boundary it uses the higher (safer) bracket.