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Yeast Conversion Calculator

Converts an amount of instant, active dry or fresh (cake) yeast into the equivalent amounts of the other two types by weight (instant 1 : active dry 1.25 : fresh 3) and expresses them in grams, teaspoons, 7 g packets and 17 g cakes.

When to use

A recipe calls for one type of yeast and you have another, or you need to convert between packets, teaspoons and grams of yeast.

Do not use when: You need the yeast amount for a dough from baker's percentages (use pizza-dough or bakers-percentage), or you are working with sourdough starter, brewing yeast or nutritional yeast.

Formula

grams = amount × (1 for g; 3.1 for tsp; 7 for a dry packet; 17 for a fresh cake); instant_g = grams / (1 instant, 1.25 active dry, 3 fresh); active_dry_g = 1.25 × instant_g; fresh_g = 3 × instant_g; tsp = g / 3.1; packets = g / 7; cakes = fresh_g / 17

Weight ratios follow manufacturer guidance (Red Star, King Arthur Baking): fresh yeast has about one third of the leavening power of instant yeast per gram and active dry about 80 %. One level teaspoon of dry yeast is taken as 3.1 g (a 7 g packet is 2¼ teaspoons); a US fresh-yeast cake is 0.6 oz (17 g), European blocks are 42 g.

Inputs

Parameter	Type	Required	Description
`amount`	number	yes	Quantity of yeast you have or the recipe calls for, in unit. Range: > 0, ≤ 10000
`unit`	enum: g \| tsp \| packet	default g	Unit of amount; a packet means a 7 g (¼ oz) dry-yeast packet, or a 17 g (0.6 oz) cake when yeast_type is fresh_cake.
`yeast_type`	enum: instant \| active_dry \| fresh_cake	yes	Type of the yeast given by amount.

Outputs

Output	Type	Unit	Description
`instant_g`	number	g	Equivalent instant yeast.
`active_dry_g`	number	g	Equivalent active dry yeast (1.25 × instant).
`fresh_g`	number	g	Equivalent fresh (cake) yeast (3 × instant).
`instant_tsp`	number	tsp	instant_g / 3.1.
`active_dry_tsp`	number	tsp	active_dry_g / 3.1.
`instant_packets`	number	packets	instant_g / 7 g.
`active_dry_packets`	number	packets	active_dry_g / 7 g.
`fresh_cakes`	number	cakes	fresh_g / 17 g (US 0.6 oz cake).
`note`	string		Handling differences between the yeast types.

Example

7 g instant yeast: {"amount":7,"unit":"g","yeast_type":"instant"} → {"instant_g":7,"active_dry_g":8.75,"fresh_g":21,"instant_tsp":2.26,"active_dry_tsp":2.82,"instant_packets":1,"fresh_cakes":1.24}

1 packet active dry yeast: {"amount":1,"unit":"packet","yeast_type":"active_dry"} → {"active_dry_g":7,"instant_g":5.6,"fresh_g":16.8,"instant_tsp":1.81,"active_dry_packets":1,"fresh_cakes":0.99}

GET https://tttkmbb.com/api/v1/calculate/yeast-conversion?amount=7&unit=g&yeast_type=instant

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/yeast-conversion (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/yeast-conversion · Markdown: https://tttkmbb.com/food/yeast-conversion.md · JSON definition: https://tttkmbb.com/food/yeast-conversion.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="yeast-conversion"
OpenAPI operationId: convert_yeast_types
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

Can I swap instant and active dry yeast 1:1?

In practice yes for most bread recipes; the 25 % difference is within the normal variation of rise times. Use the exact conversion for large batches or when timing matters.

Why is a 7 g packet 2¼ teaspoons but the calculator shows 2.26?

Because 3.1 g per teaspoon is a rounded average (7 g / 2.25 tsp = 3.11 g); the difference is far below what a measuring spoon can resolve.

How do I use fresh yeast?

Crumble it into the recipe's lukewarm liquid (or directly into the dough) and use within its short shelf life (about 2 weeks refrigerated); it should smell yeasty, not sour.

Related calculators

Pizza Dough Calculator — Yeast amount for pizza dough by baker's percentage.
Baker's Percentage Calculator — Scale yeast with the rest of a bread formula.
Baking Substitution Calculator — Substitutes for other baking ingredients.