Herb Conversion Calculator — fresh, dried and ground

This herb conversion calculator moves a quantity between the three forms a recipe might call for — fresh chopped, dried crumbled leaf, and ground or powdered — using the conversion that university extension services have published for decades, with the ratios exposed as editable fields so you can adjust them for your own jars.

Arb Digital publishes free reference tools, and this one is deliberately honest about its limits. Herb conversion is approximate in a way that most kitchen conversions are not, because the ratio depends on the herb, on how it was dried, and on how long it has been sitting in a cupboard. The tool gives you the published starting point and tells you which direction to adjust.

What This Herb Conversion Calculator Does

Enter an amount in teaspoons, tablespoons, cups or millilitres, say which form the recipe specifies, and pick the form you actually have. The calculator converts through a common internal reference and returns the equivalent in all three forms at once, so you can see the whole relationship rather than a single number. The result grid always shows fresh, dried and ground side by side.

Two ratio fields control the conversion: the fresh-to-dried ratio, published as three to one, and the dried-to-ground ratio, published as four to one. A third control applies a modest adjustment for herbs that survive drying well or badly, and that one is labelled clearly as a cook's judgement rather than a sourced figure, because no extension service publishes a per-herb table of that kind.

How to Use It

1. Enter the amount as the recipe gives it, in whichever unit it uses.
2. Set the form the recipe specifies. A recipe that says "1 tbsp chopped basil" means fresh; one that says "1 tsp oregano" almost always means dried crumbled leaf.
3. Set the form you have. Ground and powdered are the same setting here.
4. Apply the herb adjustment if it helps. Nudge delicate herbs up and robust ones down.
5. Season, taste, adjust. The calculator gives a starting quantity, not a final one.

The Published Ratios and Where They Come From

Penn State Extension's guide to preserving herbs by drying gives the conversion in one line: "1 Tablespoon fresh herbs = 1 tsp dried herbs = ¼ tsp powdered herb." Since a tablespoon is three teaspoons, that is a three-to-one fresh-to-dried ratio and a four-to-one dried-to-ground ratio, which is exactly what this calculator uses by default.

The reason is concentration. Penn State states that "dried herbs are 3 to 4 times stronger than fresh herbs", and Illinois Extension's More Herbs, Less Salt puts the same relationship the other way round: "typically you will use three times the amount of fresh herbs as dried herbs, giving us a 3:1 ratio." Drying removes water, not flavour compounds, so the same mass of plant material occupies far less volume and tastes correspondingly stronger per spoonful.

Why the Ratio Is a Range, Not a Constant

Both sources give three to four rather than a single number, and that spread is real. How much flavour survives drying depends on the herb's volatile oil profile, on drying temperature and speed, and on how the herb has been stored since. Illinois Extension's practical test is better than any ratio: rub a little between your fingers, and "if it's fragrant and smells pleasant, you're good to go. If you can't smell much or the aroma is musty or off, toss in the trash."

Storage matters more than most cooks assume. Illinois Extension notes that dried herbs and spices "can last up to 2 years", with a six-monthly check recommended, and Penn State advises airtight containers kept cool, dry and dark. A jar of oregano that has been open on a sunny shelf for three years is not three times stronger than fresh; it may be weaker. The ratio field is editable because your jar, not the average jar, is the one you are cooking with.

Robust Herbs and Delicate Herbs Behave Differently

Woody, resinous herbs — rosemary, thyme, oregano, marjoram, sage, bay — carry their aroma in relatively stable oils and come through drying with most of their character intact. In many long-cooked dishes the dried version is genuinely preferable, because those oils release slowly into fat and liquid over time.

Soft-leaved herbs are the opposite case. Basil, parsley, chives, dill, tarragon, mint and coriander leaf carry much of their aroma in highly volatile compounds that largely leave during drying. Dried basil is not concentrated fresh basil; it is a different, flatter ingredient, and no ratio converts one into the other. This is why the herb adjustment nudges delicate herbs upwards by a quarter and why the honest advice for basil and coriander leaf is to use fresh, or to substitute a different herb entirely rather than a dried version of the same one.

Why the Calculator Stays in Volume

Almost every conversion tool we publish tells you that weight beats volume, and that is true here as well — but only in principle. A teaspoon of crumbled bay leaf and a teaspoon of ground cinnamon differ in mass by a factor of several, and a teaspoon of coarsely crumbled oregano weighs less than a teaspoon of the same oregano rubbed fine. Weighing would remove all of that variation.

The difficulty is that the published conversion convention itself is volumetric — the sources give tablespoons and teaspoons, not grams — and per-herb gram weights per teaspoon vary so much by cut, crumb size and moisture that publishing a table of them would create more error than it removed. So this page stays in the units its sources use, and says plainly that the result is an approximation. Where you do want mass, the cooking measurement converter handles volume-to-weight for common ingredients.

When to Add Herbs, Which the Ratio Says Nothing About

Timing changes the outcome as much as quantity. Dried herbs benefit from time in liquid and heat, so they go in early — with the aromatics, or at the start of a simmer — where the oils have a chance to disperse. Fresh soft herbs go in at the end or off the heat entirely, because sustained heat destroys exactly the compounds you added them for.

This means a straight substitution sometimes needs a change of method rather than just a change of quantity. Swapping fresh parsley for dried in a finishing garnish will disappoint no matter what the calculator says, because the problem is not the amount. Swapping dried thyme for fresh in a braise, on the other hand, works fine at the published ratio. The same logic applies to whole spices and seeds, which release slowly and reward early addition, and to delicate finishing herbs, which reward being kept out of the pot entirely until the heat is off.

Common Mistakes to Avoid

• Substituting dried for fresh in a finishing garnish. The ratio fixes quantity, not the fact that dried soft herbs taste dusty raw.
• Assuming ground and crumbled are the same. Ground herb is roughly four times stronger by volume than crumbled leaf, so a teaspoon of one is not a teaspoon of the other.
• Using old dried herbs at the full ratio. Herbs that have lost their aroma are not three times stronger than fresh. Smell them first.
• Treating basil and coriander leaf as convertible. Their aroma compounds largely do not survive drying, so the dried version is a different ingredient rather than a concentrate.
• Adding dried herbs at the end of cooking. They need heat and liquid and time to release. Fresh soft herbs need the opposite.

Related Free Tools From Arb Digital

For general kitchen unit work, use the cooking measurement converter or the grams to ounces converter. If you are seasoning by percentage rather than by spoon, the brine calculator and the salt to sodium converter both work that way, and the butter oil substitution calculator handles fat swaps on the same weight-first principle. For a herb-heavy grill menu, see the BBQ food calculator. The full free online tools hub lists everything else.

Frequently Asked Questions

Herb conversions are approximations. The ratio between fresh, dried and ground forms varies by herb, by drying method and by how long the dried herb has been stored, so treat any result as a starting quantity and season to taste.