Why liquid sweeteners need a recipe adjustment, not just a swap
Granulated sugar is a dry ingredient; honey and maple syrup are liquids that are also sweeter by volume than granulated sugar — using the same volume of honey as sugar would both over-sweeten the recipe and add unaccounted-for liquid, which can make a batter too thin or throw off a bake's structure. That's why the standard conversion uses less liquid sweetener by volume (about ¾ cup honey per 1 cup sugar) and also calls for reducing another liquid ingredient in the recipe (milk, water) by a few tablespoons to compensate for the extra moisture honey itself brings. Honey and maple syrup also both contain natural sugars that brown faster than granulated sugar, which is why recipes using them often lower the oven temperature slightly to avoid over-browning before the inside finishes baking.
Coconut sugar and brown sugar — the simpler swaps
Coconut sugar and brown sugar are both still dry, granular sugars, so neither needs a liquid adjustment the way honey or maple syrup do — they're much closer to a true 1:1 swap. Coconut sugar is slightly less sweet and brings a mild caramel note; brown sugar adds moisture (from its molasses content) and a deeper flavor, which is part of why it's often specifically called for in recipes wanting a chewier texture, like many cookie recipes.
FAQ
What about stevia or other zero-calorie sweeteners? These vary enormously by brand and concentration — always follow the specific product's own conversion chart rather than a general rule, since pure stevia extract is vastly more concentrated than a sugar-blend product like Truvia Baking Blend.
Do I need to reduce liquid for coconut sugar too? No — coconut sugar behaves like a dry sugar in this respect, unlike honey or maple syrup.