# Curing Salt Calculator

> Computes the grams of Prague powder #1 or #2 (6.25 % sodium nitrite) needed to reach a target ingoing nitrite concentration in parts per million for an equilibrium dry cure or wet brine, plus the extra salt (net of the salt contained in the cure) and sugar for chosen percentages of the total meat and water mass.

- Calculator id: `curing-salt` · Category: Food & Cooking (`food`) · Tool name: `calculate_curing_salt`
- Canonical page: https://tttkmbb.com/food/curing-salt · This document: https://tttkmbb.com/food/curing-salt.md · JSON definition: https://tttkmbb.com/food/curing-salt.json

## Purpose

Computes the grams of Prague powder #1 or #2 (6.25 % sodium nitrite) needed to reach a target ingoing nitrite concentration in parts per million for an equilibrium dry cure or wet brine, plus the extra salt (net of the salt contained in the cure) and sugar for chosen percentages of the total meat and water mass.

**Use when:** You are making bacon, ham, pastrami, corned beef or salami with an equilibrium (measured-percentage) cure and need exact cure, salt and sugar weights for a given meat weight.

**Do not use when:** You are using a traditional excess-salt dry cure, a commercial pre-mixed cure with its own dosage, or a plain salt brine without nitrite (use brine); regulatory limits must never be exceeded.

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `meat_weight_kg` | number | kg | required | Weight of the meat to cure, in kilograms. (> 0, max 500) |
| `cure_type` | enum: prague_powder_1 \| prague_powder_2 |  | optional, default "prague_powder_1" | Cure #1 for products cured within days and then cooked; cure #2 for salami and whole-muscle dry cures lasting weeks, where the nitrate converts slowly to nitrite. |
| `target_nitrite_ppm` | number | ppm | optional, default 156 | Sodium nitrite in mg per kg of total mass. USDA ingoing limits: 200 ppm for immersion-cured or massaged whole muscle, 156 ppm for comminuted products (sausage), 120 ppm for pumped bacon. (min 50, max 200) |
| `salt_percent` | number | % | optional, default 2 | Total salt as a percentage of the total mass, including the salt in the cure; 1.75–2.5 % is typical for bacon and ham, 2.5–3 % for salami. (min 0, max 10) |
| `sugar_percent` | number | % | optional, default 1 | Sugar as a percentage of the total mass (0.5–1.5 % typical). (min 0, max 10) |
| `method` | enum: dry_equilibrium \| wet_brine_equilibrium |  | optional, default "dry_equilibrium" | Dry cures are dosed on the meat weight; equilibrium brines on meat plus water weight. |
| `water_weight_kg` | number | kg | optional | Water in the brine in kilograms (1 L = 1 kg); required for wet_brine_equilibrium and ignored for dry cures. (min 0, max 500) |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `total_mass_g` | number | g | Meat (plus water for a brine) on which the cure, salt and sugar are dosed. |
| `cure_grams` | number | g | Prague powder to add; weigh it on a 0.1 g scale. |
| `cure_teaspoons_approx` | number | tsp | Approximate volume at about 6 g per level teaspoon; for information only, never dose by volume. |
| `nitrite_mg` | number | mg | Nitrite delivered by the cure (= target ppm × total mass in kg). |
| `nitrate_mg` | number | mg | Nitrate delivered (Prague powder #2 only; 0 for #1). |
| `salt_from_cure_grams` | number | g | The cure is 93.75 % (#1) or 89.75 % (#2) plain salt. |
| `salt_grams` | number | g | Plain salt to add so that the total salt equals salt_percent of the mass. |
| `total_salt_grams` | number | g | Extra salt plus the salt contained in the cure. |
| `sugar_grams` | number | g | Sugar to add. |
| `total_salt_percent` | number | % | Total salt as a percentage of the total mass. |
| `safety_warning` | string |  | Handling and dosing warnings for nitrite cures. |

## Formula

`total_mass_g = 1000 × (meat_weight_kg + water_weight_kg for a wet brine); cure_g = total_mass_g × target_nitrite_ppm / 62 500 (the cure is 6.25 % sodium nitrite); nitrite_mg = cure_g × 62.5; nitrate_mg = cure_g × 40 (#2 only); salt_from_cure = cure_g × 0.9375 (#1) or 0.8975 (#2); total_salt_g = total_mass_g × salt_percent / 100; salt_g = total_salt_g − salt_from_cure; sugar_g = total_mass_g × sugar_percent / 100; teaspoons ≈ cure_g / 6`

Equilibrium curing doses every ingredient as a fixed percentage of the total mass, so the product cannot over-salt or over-cure however long it sits; the meat reaches the target concentration after about 1 day per 1.3 cm of thickness plus 2 days. USDA ingoing nitrite limits (9 CFR 424.21) are 200 ppm for immersion-cured or massaged products, 156 ppm for comminuted products and 120 ppm for pumped bacon (with 550 ppm sodium ascorbate or erythorbate).

## Data Sources

- 9 CFR 424.21(c) – Use of food ingredients: curing agents (ingoing nitrite limits) — https://www.ecfr.gov/current/title-9/chapter-III/subchapter-E/part-424/subpart-C/section-424.21 (government, retrieved 2026-09-24)
- USDA FSIS – Bacon and Food Safety (nitrite in curing; 120 ppm limit for pumped bacon) — https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/meat-catfish/bacon-and-food-safety (government, retrieved 2026-09-24)
- Wikipedia – Curing salt (Prague powder #1: 6.25 % sodium nitrite; #2 adds 4 % sodium nitrate) — https://en.wikipedia.org/wiki/Curing_salt (reference, retrieved 2026-09-24)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/curing-salt?meat_weight_kg=…`
- `POST https://tttkmbb.com/api/v1/calculate/curing-salt` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/curing-salt · OpenAPI operationId `calculate_curing_salt` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "curing-salt", "inputs": {…}}`

## Example

- 1 kg pork belly, dry equilibrium cure, 156 ppm, 2 % salt, 1 % sugar: inputs `{"meat_weight_kg":1,"cure_type":"prague_powder_1","target_nitrite_ppm":156,"salt_percent":2,"sugar_percent":1,"method":"dry_equilibrium"}` → `{"total_mass_g":1000,"cure_grams":2.5,"nitrite_mg":156,"salt_from_cure_grams":2.34,"salt_grams":17.7,"total_salt_grams":20,"sugar_grams":10,"total_salt_percent":2,"cure_teaspoons_approx":0.42}`
- 2 kg ham in 1 kg water brine, 120 ppm, 2.5 % salt: inputs `{"meat_weight_kg":2,"cure_type":"prague_powder_1","target_nitrite_ppm":120,"salt_percent":2.5,"sugar_percent":1,"method":"wet_brine_equilibrium","water_weight_kg":1}` → `{"total_mass_g":3000,"cure_grams":5.76,"nitrite_mg":360,"salt_grams":69.6,"sugar_grams":30,"cure_teaspoons_approx":0.96}`

```
GET https://tttkmbb.com/api/v1/calculate/curing-salt?meat_weight_kg=1&cure_type=prague_powder_1&target_nitrite_ppm=156&salt_percent=2&sugar_percent=1&method=dry_equilibrium
```

## Limitations

You are using a traditional excess-salt dry cure, a commercial pre-mixed cure with its own dosage, or a plain salt brine without nitrite (use brine); regulatory limits must never be exceeded. Equilibrium curing doses every ingredient as a fixed percentage of the total mass, so the product cannot over-salt or over-cure however long it sits; the meat reaches the target concentration after about 1 day per 1.3 cm of thickness plus 2 days. USDA ingoing nitrite limits (9 CFR 424.21) are 200 ppm for immersion-cured or massaged products, 156 ppm for comminuted products and 120 ppm for pumped bacon (with 550 ppm sodium ascorbate or erythorbate). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Why is the extra salt less than 2 % of the meat?**

Because Prague powder is itself about 94 % salt; the calculator subtracts that so the total salt, cure included, equals the chosen percentage.

**Can I use Prague powder #2 for bacon?**

No. #2 contains nitrate meant to release nitrite slowly over weeks of dry curing; bacon, ham and other products cured for days and then cooked use #1 only.

**What if I only have Morton Tender Quick or a pre-mixed cure?**

Those are different formulations (Tender Quick is 0.5 % nitrite and 0.5 % nitrate) and must be dosed by the manufacturer's instructions, not with this calculator.

## Related

- [Brine Calculator](https://tttkmbb.com/food/brine.md) — Plain salt brine without nitrite.
- [Meat Cooking Time Calculator](https://tttkmbb.com/food/meat-cooking-time.md) — Roasting the cured joint afterwards.
- [Mass / Weight Converter](https://tttkmbb.com/conversion/mass.md) — Convert pounds of meat to kilograms.