Canning Recipe Scaler
Safely scale your canning recipes for larger or smaller batches. Maintains proper acid levels, headspace, and processing times.
Scale Your Recipe
Scaled Recipe
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Scale Factor
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Required Headspace
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Processing Time
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Pressure (Pressure Canner)
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 (11 PSI at 1,000-2,000 ft, up to 15 PSI at 6,000+ ft).
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.