# Calculate Canning Quantities and Times

> Jar quantities, canner loads, and processing times for home canning. Half-pint, pint, and quart jars with altitude adjustment and annual supply planning.

Live tool: https://lofttools.com/tools/cooking-tools/canning-calculator

Category: Cooking & Kitchen

## How it works

1. **Select food type** — Choose the fruit, vegetable, or preserve you are canning
2. **Enter quantity** — Input the pounds or kilograms of produce
3. **Pick jar size** — Choose half-pint, pint, or quart to match your recipe
4. **See jars and timing** — View jar count, canner loads, headspace, and processing time — with altitude adjustment

## FAQ

### What formulas does this calculator use?

Jars = produce weight (lbs) × USDA/NCHFP yield per lb for the selected jar size. Half-pint yield is derived as pint yield × 2 (same volume, twice the jars). Canner loads = ceil(jars ÷ canner capacity), using standard capacities of 7 quart / 9 pint / 12 half-pint for water-bath and 7 quart / 16 pint / 20 half-pint for pressure canners. Altitude adjustment adds 5 min per 1,000 ft above 1,000 ft for water-bath and 5 PSI per 2,000 ft above 2,000 ft for pressure canning.


### How does altitude affect canning?

At higher elevations water boils at a lower temperature, so food needs longer processing (water-bath) or higher pressure (pressure canner) to reach a safe preserving temperature. Enter your altitude in feet and the calculator adjusts time or PSI automatically using the USDA schedule.


### What jar sizes are supported?

Half-pint (8 oz), pint (16 oz), and quart (32 oz). Half-pints are the standard jar for jams and jellies; quarts are typical for whole fruit and pressure-canned vegetables.


### How does the annual supply planner work?

Enter your household size and how many servings of the selected food you eat per person per week. Using a USDA half-cup serving (2 servings per half-pint, 4 per pint, 8 per quart), the planner calculates jars needed for 52 weeks plus the produce weight (lb and kg) required to fill them.


### When do I use water bath vs pressure canning?

USDA / NCHFP draws the line at pH 4.6. High-acid foods (pH ≤ 4.6, things like jams, jellies, fruit, pickles, acidified salsa, tomatoes with added acid, chutneys, fruit butters) are safe in a water-bath canner because the acidity itself blocks botulism. Low-acid foods (pH > 4.6, including plain vegetables, meats, seafood, soups, stocks, mixed vegetables, cubed pumpkin) must be processed in a pressure canner to reach 240 °F / 116 °C and destroy Clostridium botulinum spores. The "USDA method guide" panel toggles between both methods to show what's safe, what's unsafe, and the altitude rule for each (water-bath: +5 min per 1,000 ft above 1,000 ft; pressure: +5 PSI per 2,000 ft above 2,000 ft). USDA explicitly warns against home-canning puréed pumpkin or squash; process cubed only.


### What foods are supported?

Eighteen foods including tomatoes, peaches, applesauce, apples, pears, plums, green beans, corn, carrots, potatoes, salsa, dill cucumbers, cucumbers, jam, jelly, beets, peas, and cabbage. Each entry carries USDA/NCHFP yield rates, headspace, processing method, base processing time, and pressure (where applicable).


## Privacy — what we do not do

This tool runs entirely in the browser via WebAssembly. Your file never reaches a Loft Tools server. Specifically:

- **No upload.** The file bytes load into the browser tab's memory and process on your own CPU. Open DevTools → Network and observe zero outbound requests carrying file data while Calculate Canning Quantities and Times runs.
- **No AI training on your file.** Loft does not train models. We could not train on a file we cannot see.
- **No content scanning.** No virus, copyright, or content-moderation pass against your file. The bytes are not accessible to us.
- **No server-side log of file contents, filenames, or EXIF metadata.** Cloudflare edge captures URL and truncated IP for abuse defense (standard CDN behaviour). Cloudflare Web Analytics records anonymous page hits, no cookies, no PII. Nothing about your file content reaches any log.
- **No retention.** Close the tab and the file leaves browser memory. No backups exist on our side because no copy ever existed on our side.
- **No account.** No email, no signup, no auth, no telemetry tied to you.
- **Offline-capable after first visit** (PWA). Once you've loaded a tool, it caches; later sessions work without internet. For high-sensitivity files, run the tool once online to warm the cache, then disconnect before processing.

Compare with upload-based services: each transmits your file to a processing server. Even over HTTPS, each has logs, retention windows, and subpoena exposure. Loft has none of these because the server architecture does not include your file.

## More

- All tools: https://lofttools.com/tools
- Category: https://lofttools.com/tools/cooking-tools
- LLM index: https://lofttools.com/llms.txt