Yeast Converter
One US packet is 2¼ tsp and 7 g. Instant needs about 25% less than active dry, and fresh yeast is about three times the weight of instant. Type what you have, get what your recipe wants.
Fractions are fine. Type 2 1/4, 1/2 or 0.75.
How this is calculated
The math Two anchors and one ratio
Anchor one: a standard US packet of dry yeast holds 7 g, which measures 2¼ teaspoons. That works out to about 3.1 g per teaspoon for both active dry and instant, and it is the number this tool measures spoons with. The packet is also labeled ¼ oz, which is 7.09 g, so 7 g and ¼ oz mean the same packet.
Anchor two: instant yeast is more concentrated in live cells than active dry, because it is dried faster and gently, so less of it does the same job. The working figure is 25% less. Going the other way, active dry is instant multiplied by 1.33.
The ratio: fresh yeast is mostly water, so it takes about three times the weight of instant to match it. Put together, the weights that do the same job are 1 part instant : 1.33 parts active dry : 3 parts fresh.
Everything on this page runs from those three figures. Nothing is rounded until it is printed, and any number this tool cannot state exactly is labeled “about”.
| Yeast | Bakery 1:2:3 shorthand | Accurate modern ratio | For 5 g instant |
|---|---|---|---|
| Instant | 1 | 1 | 5 g |
| Active dry | 2 | 1.33 | 6.7 g |
| Fresh / cake | 3 | 3 | 15 g |
Which one should you use? The 1:2:3 version is a memory hook from professional bakeries, and it is the one you will hear shouted across a bakery floor. It is right about fresh yeast and wrong about active dry: it doubles instead of adding a third. Modern active dry is dried far better than the product that rule was invented for, so 2x now overproofs. Use the accurate column, which is what this converter runs on. Keep 1:2:3 for the fresh-yeast half, where it still holds.
One honest wrinkle on fresh yeast. Our ratio gives about 15.8 g of fresh for one 7 g packet of active dry, but manufacturers sell a 0.6 oz (17 g) cake and label it as the replacement for exactly one packet. Both are defensible, so treat 15 to 19 g of fresh per packet as the real range and do not agonize over a gram. Yeast is a living thing that eats its way to the finish line; the amount sets the speed, not the outcome.
Baker’s percentage helper
Recipes give you a fixed amount of yeast. Bakers give you a percentage of the flour weight, which is what actually controls how fast the dough rises. Enter your flour weight and pick how long you want to wait.
Grams of flour. A standard sandwich loaf is 500 g, a big batch of pizza dough 1000 g.
Worth knowing Less yeast and more time is the better trade
Yeast makes gas, which makes the loaf rise. Time makes flavor, because the slower fermentation also produces acids, alcohols and esters that a fast rise never gets around to building. Those two jobs pull in opposite directions: the more yeast you add, the sooner the dough is ready and the less of that flavor it has developed on the way.
This is why the same 500 g of flour can take 6 g of instant yeast or 0.4 g of it, and both are correct. The 6 g loaf is out of the oven in three hours and tastes mainly of yeast. The 0.4 g loaf sits in the fridge overnight and tastes of wheat. If you have the time, cut the yeast and use it.
The ranges above are working figures used across home and craft baking, not a standard anyone publishes. Kitchen temperature moves them more than anything else: dough ferments roughly twice as fast at 80°F as at 65°F, so a cool winter kitchen wants the higher end of a range and a hot August kitchen the lower end. Watch the dough, not the clock.
Proofing yeast, and what it is actually for
Proofing means dissolving yeast in warm water with a pinch of sugar and waiting for foam. The instruction survives in thousands of recipes, and most of them explain it wrong.
Modern active dry yeast does not need to be dissolved. The active dry sold today is milled finer than the product that rule was written for, and every major manufacturer now states it can be added straight to the dry ingredients like instant. What proofing still does, and does well, is tell you whether the jar in your cupboard is alive before you commit 500 g of flour to it. Treat it as a freshness test, not a required step.
Instant yeast never needed proofing and is designed to be mixed into the flour dry. If you proof it anyway, nothing bad happens. Fresh yeast crumbles into the liquid and dissolves on its own.
Do this The freshness test, step by step
Stir 1 teaspoon of yeast and ½ teaspoon of sugar into ¼ cup (60 ml) of water at 110 to 115°F, which is warm on the inside of your wrist but not hot. Leave it somewhere warm and look at it after 10 minutes.
A thick foam cap, roughly doubling in the cup: the yeast is alive and strong. Use it, and subtract the water and yeast you used from the recipe.
A few bubbles and no real foam: weakening. It will probably still work, but give the dough longer than the recipe says and do not use it for anything you care about.
Nothing at all after 10 minutes: dead. No amount of extra time fixes it. Throw it out rather than losing a bag of flour to it.
| Water | Celsius | What happens to the yeast |
|---|---|---|
| Below 70°F | Below 21°C | Alive but sluggish. Fine for a slow dough, too slow to prove a jar is good. |
| 100 to 110°F | 38 to 43°C | Active and comfortable. Safe for any yeast. |
| 110 to 115°F | 43 to 46°C | The proofing sweet spot. Fastest visible foam with no damage. |
| 120°F | 49°C | Damage begins. Cells start dying and the rise gets unreliable. |
| 130°F and above | 54°C and above | Dead. Nothing you do afterward brings it back. |
Hot tap water in most homes runs 120 to 140°F, which is inside the kill zone. That is the single most common way home bakers murder their yeast. If you do not want to use a thermometer, mix hot and cold until the water feels pleasantly warm rather than hot, or use plain lukewarm water and accept a slower rise. Cold water never kills yeast. It only slows it down.
Storage, shelf life and telling if yeast is dead
| Yeast | Unopened | Once opened |
|---|---|---|
| Active dry | About 2 years in a cool dry cupboard, to the printed date | Airtight: 4 to 6 months in the fridge, up to a year in the freezer |
| Instant | About 2 years in a cool dry cupboard, to the printed date | Airtight: 4 to 6 months in the fridge, up to a year in the freezer |
| Fresh / cake | 2 to 3 weeks refrigerated, and that is the whole shelf life | Use within a few days. It does not freeze well. |
The rules that matter. Air and moisture kill dry yeast far faster than time does, so once the vacuum seal is broken, get it into an airtight jar and into the fridge or freezer the same day. Yeast can be used straight from the freezer with no thawing and no change to the recipe. Never scoop with a wet spoon, and never store the jar above the stove, which is the warmest and dampest spot in most kitchens.
How to tell if it is dead. Look first: good fresh yeast is firm, evenly pale cream and smells faintly of beer. If it is brown at the edges, slimy, dry and crumbling, or smells sour or of nothing at all, it is finished. For dry yeast there is no look that proves anything, so run the freshness test above. A date on the jar is not evidence either way. A well stored jar six months past its date will often foam happily, and a jar left open on a humid counter can be dead a month before its date.
If you are still deciding which yeast to buy in the first place, our guide to active dry versus instant yeast covers how they are made, how they behave in a real dough and when the difference actually shows up in the loaf.
Quick reference chart
The conversions people look up most, worked out from 7 g per packet and the 1 : 1.33 : 3 ratio. Screenshot it and keep it with your bread flour.
| If the recipe says | Active dry | Instant | Fresh |
|---|---|---|---|
| ½ packet | 3.5 g / 1⅛ tsp | 2.6 g / ⅞ tsp | 7.9 g |
| 1 packet | 7 g / 2¼ tsp | 5.3 g / 1¾ tsp | 15.8 g |
| 1½ packets | 10.5 g / 3⅜ tsp | 7.9 g / 2½ tsp | 23.6 g |
| 2 packets | 14 g / 4½ tsp | 10.5 g / 3⅜ tsp | 31.5 g |
| 1 tsp active dry | 3.1 g | 2.3 g / ¾ tsp | 7 g |
| 1 tbsp active dry | 9.3 g | 7 g / 2¼ tsp | 21 g |
| 1 tsp instant | 4.2 g / 1⅜ tsp | 3.1 g | 9.3 g |
| 10 g fresh | 4.4 g / 1⅜ tsp | 3.3 g / 1⅛ tsp | 10 g |
| 1 cake (0.6 oz, 17 g) fresh | 7.6 g / 2⅜ tsp | 5.7 g / 1⅞ tsp | 17 g |
| 1 cake (2 oz, 57 g) fresh | 25.2 g / 8⅛ tsp | 18.9 g / 6⅛ tsp | 57 g |
Teaspoons are level and snapped to measurable eighths, because your spoon set does not have a “1.36 tsp”. Where a spoon figure has been rounded to fit a real spoon, the gram figure beside it is the exact one. When the two disagree, trust the grams.
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Questions bakers actually ask
Can I swap instant yeast for active dry one for one?
You can, and plenty of bakers do, but the dough will rise faster than the recipe expects. Instant yeast is more concentrated, so a straight swap gives you roughly a third more leavening power than intended. For a forgiving dough like pizza or focaccia that is barely a problem; for a sandwich loaf on a schedule it means checking the dough half an hour earlier than the recipe says.
The accurate swap is to use 25% less instant than the active dry called for, or 33% more active dry than the instant called for. Set the converter above to the yeast you have and read the number off the card for the yeast the recipe wants.
How many teaspoons is a packet of yeast?
2¼ teaspoons, which is 7 g, which is the ¼ oz printed on the strip. That is the same for active dry and for instant, since manufacturers fill both to the same net weight. It is also almost exactly ¾ of a tablespoon, so if you are measuring a lot of packets, 4 packets is 3 tablespoons.
Packets outside the United States are not always 7 g. European sachets are commonly 7 g too, but 5 g, 8 g and 11 g sachets all exist, and some brands size the sachet to a specific flour weight instead. Read the strip rather than assuming.
Do I still have to proof active dry yeast in warm water?
No. Active dry yeast made today can be mixed straight into the flour, and the manufacturers say so on their own websites. The dissolving step is a leftover from an older, coarser product that genuinely needed rehydrating before it would wake up.
What proofing is still worth doing for is checking the yeast is alive, especially with a jar that has been open a while or has passed its date. Ten minutes and a quarter cup of water is a cheap insurance policy against wasting a batch of dough. If you know the yeast is fresh, skip it.
What water temperature kills yeast?
Damage starts at about 120°F (49°C) and yeast is reliably dead at 130°F (54°C) and above. The proofing sweet spot is 110 to 115°F (43 to 46°C), warm enough for a quick visible foam and comfortably below the danger line.
The practical warning is about your tap. Hot water heaters are commonly set to 120 to 140°F, which means straight hot tap water can be lethal to yeast on contact. If you are not measuring, aim for water that feels barely warm on the inside of your wrist rather than hot. Cold water is never a risk, only a delay.
How much fresh yeast replaces a packet of dry yeast?
Roughly 15 to 19 g of fresh yeast per 7 g packet. The ratio math gives 15.8 g, while manufacturers sell a 0.6 oz (17 g) cake and label it as the direct replacement for one packet. Both answers are in circulation and neither is wrong enough to matter in a loaf.
Crumble fresh yeast into the liquid rather than into the flour, and give the dough a little longer than a dry-yeast recipe suggests, since fresh yeast starts slower. Fresh yeast is not sold in most American supermarkets and keeps only two to three weeks, which is why nearly every home recipe assumes dry.
How much yeast do I need for 500 g of flour?
It depends entirely on how long you want to wait, which is why the helper above asks. For a standard 2 to 3 hour rise, about 3.5 g of instant (1⅛ tsp) or 4.7 g of active dry (1½ tsp). For an overnight cold ferment, as little as 0.8 g of instant, which is a quarter teaspoon.
Both loaves work. The overnight one tastes noticeably better, because the flavor compounds that make bread taste of something other than yeast take hours to build. If your schedule allows it, the smaller number is almost always the better bake.
Is rapid rise yeast the same as instant yeast?
Close enough to use this converter for both. Rapid rise, quick rise, fast acting and bread machine yeast are all instant yeast, and they all convert against active dry at the same 25% figure. Some rapid rise products add extra ascorbic acid or enzymes to speed the first rise further, which is a marketing difference more than a measuring one.
The one real caution is that rapid rise brands sometimes tell you to skip the first rise entirely. That is a recipe instruction, not a property of the yeast, and skipping the first rise costs you flavor. You can always treat rapid rise as ordinary instant yeast and give the dough its full time.
Can I use too much yeast?
Yes, and it shows up as taste rather than as a failure to rise. Too much yeast gives you a dough that races ahead of the schedule, a coarse open crumb with big irregular holes, a strong beery or sour smell, and a loaf that can collapse in the oven because the gluten never had time to build enough strength to hold the gas.
Anything above roughly 2% of the flour weight is a lot for a home loaf. If your bread rises beautifully and then sinks, or tastes aggressively of yeast, cutting the yeast and lengthening the rise fixes both problems at once.
Ratios are working figures from standard baking practice and manufacturer guidance. Where sources differ, this page gives the range. Last reviewed August 2026.