Canning Recipe Scaler

Safely scale your canning recipes for larger or smaller batches. Maintains proper acid levels, headspace, and processing times.

Scale Your Recipe

Processing time differs by jar size — quart jars require longer processing
Processing times increase at altitudes above 1,000 feet

Enter one ingredient per line: Name:Amount:Unit (e.g., "Tomatoes:10:lbs")

Scaled Recipe

Scale Factor
Required Headspace
Processing Time
Pressure (Dial / Weighted)

Scaled Ingredient Quantities

Ingredient Original Scaled Notes

How It Works

Canning recipe scaling isn't as simple as multiplying everything by a factor. Some ingredients and parameters must remain constant regardless of batch size to ensure food safety.

Safety Rules for Scaling

  • Acid ingredients (vinegar, lemon juice, citric acid): MUST scale proportionally. Never reduce the acid content, as it's critical for preventing botulism in water bath canning.
  • Sugar: In jams and jellies, sugar can be reduced up to 50% of the original amount when using low-sugar pectin. In standard recipes, maintain at least 50% for safe gelling.
  • Spices and herbs: Scale proportionally, but small adjustments to taste are safe.
  • Headspace: Never changes with batch size. Always use the headspace specified in the original recipe.
  • Processing time: Never changes based on batch size. Only altitude affects processing time.

Water Bath vs. Pressure Canning

  • Water Bath (212°F): Safe only for high-acid foods (pH < 4.6) such as fruits, pickles, jams, and acidified tomatoes.
  • Pressure Canner (240°F): Required for low-acid foods (pH > 4.6) such as vegetables, meats, and stocks.

Altitude Adjustments

Water boils at lower temperatures at higher elevations, so processing times must be increased:

  • 1,000 - 3,000 ft: +5 minutes
  • 3,000 - 6,000 ft: +10 minutes
  • 6,000 - 8,000 ft: +15 minutes
  • 8,000 - 10,000 ft: +20 minutes

For pressure canning, increase pressure instead. Dial gauge: 11 PSI at 1,000–2,000 ft, 12 PSI at 2,000–4,000 ft, 13 PSI at 4,000–6,000 ft, 14 PSI at 6,000–8,000 ft, 15 PSI above 8,000 ft. Weighted gauge: 10 PSI at sea level (≤1,000 ft), 15 PSI at any altitude above 1,000 ft. Always use the gauge type your canner is equipped with — when in doubt, consult your canner's manual and USDA Complete Guide to Home Canning.

Scale Factor = Desired jars / Original jars Each ingredient amount = Original amount × Scale Factor Safety Rule: DO NOT scale tomato/salsa water-bath recipes more than 2× without a verified source recipe. Pressure-canned recipes are safe to scale proportionally. Processing Time Adjustments (altitude): Water bath at sea level: 35 min (tomatoes) Water bath at 1,000-3,000 ft: +5 min Water bath at 3,000-6,000 ft: +10 min Water bath at 6,000-8,000 ft: +15 min Water bath at 8,000-10,000 ft: +20 min Pressure Canner PSI by altitude: Sea level - 1,000 ft: 10 PSI (weighted gauge) / 11 PSI (dial gauge) 1,000 - 2,000 ft: 11 PSI 2,000 - 4,000 ft: 12 PSI 4,000 - 6,000 ft: 13 PSI 6,000 - 8,000 ft: 14 PSI 8,000 - 10,000 ft: 15 PSI
Important: Always use tested recipes from trusted sources (USDA, Ball, NCHFP) when scaling. This calculator provides estimates only — follow the instructions from your verified recipe for safe canning.