How to Build Your Own Custom Ingredient Conversion Chart

Published figures, including the ones on this site, are averages. Granulated sugar at 4.2 g per teaspoon and table salt at 6.0 g are derived from reference bulk densities that hold well across brands. Flour at 2.6 g and cocoa at 1.8 g hold much less well, because those ingredients respond strongly to milling, brand, storage and how the cook handles them.

Three sources of variation a generic table cannot account for: your specific brand, whose particle size may differ from the reference; your measuring spoons, which are manufactured to loose tolerances and are often several percent off nominal; and your technique, which is consistent for you and different from the next person.

None of that makes published tables wrong. It makes them a starting point. A chart you measured yourself collapses all three sources of variation into one number, and that number is repeatable — which is the property that actually improves your baking.

It also lets you cover ingredients no general table includes: the specific brand of rye flour you buy, your regional salt, a spice blend you mix yourself, a nut flour, a protein powder.

You need a scale that reads to 0.1 g, one set of measuring spoons, and a straight edge. A 1 g scale will do for larger spoons but is too coarse for a single teaspoon of a light powder.

Loosen the ingredient in its container first — stir with a fork or shake the bag — because the point is to capture your normal measurement, not a compacted one from the bottom of a jar.

Tare a small bowl on the scale. Fill your teaspoon by spooning or pouring the ingredient in, never by dipping the spoon into the container, then sweep it level with the straight edge. Tip it into the bowl. Repeat five times without re-taring.

Divide the total by five. That is your grams-per-teaspoon figure. Five spoonfuls rather than one matters: a single teaspoon of cocoa weighs under 2 g, so on a 0.1 g scale one measurement carries about 5% rounding error, while five carries about 1%.

Sanity check against a reference. If your figure is within 10% of the published number, you have measured well. If it is 40% off, you have probably scooped rather than spooned, or your spoon is not the size stamped on it.

One number gives you the entire row of a conversion chart, because every other US volume unit is an exact multiple of the teaspoon. It also gives you both directions at once: multiply for tsp to g, divide for grams to teaspoons.

Do not measure everything. Most of the value comes from a short list, and the rest of a published table is fine as it stands.

Measure the ingredients you use in quantity and whose published figures are least stable: your flours above all, since flour is both the largest ingredient by weight and the most technique-sensitive, at a nominal 2.6 g per teaspoon spooned.

Measure your salt. The published spread runs from 2.8 g per teaspoon for Diamond Crystal to 6.0 g for fine table salt, and where your particular salt falls in that range determines whether your food is seasoned or oversalted.

Measure anything specialty: whole grain and nut flours, unrefined sugars, home-mixed spice blends, cocoa (nominally 1.8 g per teaspoon but highly variable between Dutch-process and natural), and any ingredient sold in bulk rather than branded packaging.

Do not bother with liquids. Water is 4.9 g per teaspoon by definition, milk 5.1 g, oils around 4.5 g, and none of them vary meaningfully between kitchens. Do not bother with granulated sugar either; it is the most consistent solid in the kitchen and the published 4.2 g will be right.

Suppose you want a figure for your wholemeal flour, which no general table covers well because protein content and bran particle size vary so much between mills.

Shake the bag. Tare a bowl. Spoon and level five teaspoons into it. The scale reads 14.2 g, so your figure is 2.84 g per teaspoon — a little denser than the 2.6 g of white all-purpose flour, which is what you would expect from bran fragments filling the gaps between starch particles.

Now the row builds itself. A tablespoon is 3 × 2.84 = 8.5 g. A cup is 48 × 2.84 = 136 g. The density is 2.84 ÷ 4.93 = 0.58 g/mL, which lets you handle a metric cup at 250 mL as 144 g if a European recipe calls for one.

The useful direction is the reverse. A recipe wanting 200 g of your wholemeal is 200 ÷ 136 = 1.47 cups — call it 1½ — and one wanting 25 g is 25 ÷ 2.84 = 8.8 teaspoons, or just under 3 tablespoons.

Compare that with what a generic "flour" figure would have told you. Using 2.6 g per teaspoon, 200 g would have come out as 1.60 cups instead of 1.47 — an error of around 9%, in the same direction, on the largest ingredient in the recipe.

A number without its conditions is only half a measurement, and six months later you will not remember which conditions applied.

Note the brand and the specific product. "Flour" is not enough; "brand X plain white flour" is. Note the date, because kitchen humidity is seasonal and hygroscopic ingredients — brown sugar, salt, baking soda, cocoa — genuinely weigh differently in a damp summer than a dry winter.

Note the technique in a word: "spooned" or "scooped", "packed" or "loose", "sifted" or "not". This is the single largest variable, and a figure recorded without it cannot be reproduced.

Note which spoon set you used, if you own more than one. Two sets will not agree, and a chart built with one and applied with the other inherits the difference between them.

A chart is only worth building if you can find it when your hands are covered in dough. Tape it inside a cupboard door at eye level, or write it on the inside cover of the notebook you actually use. A spreadsheet on a phone in the next room does not get consulted.

Re-measure when something changes: a new brand, a new bag from a different mill, a new set of spoons, or a move to a different climate. Otherwise once is enough — these figures do not drift on their own.

And keep the direction you actually use. Most people need grams-to-teaspoons, because recipes give weights and kitchens have spoons. Writing the row as "10 g = 3.8 tsp" saves you doing a division while a mixer is running, which is exactly when a division goes wrong.