Tools

Three keto and low-carb calculators, free and with no sign-up. They answer three different questions: what a package really costs you in carbs, how much to eat in a day, and how much sweetener replaces the sugar a recipe wants. Each one shows its math and links to the guide behind it.

Which calculator answers which question

Pick by the question in front of you, not by the name of the tool. Most people need the macro calculator once, the net carb calculator in a supermarket aisle, and the converter only when they bake.

Your question	Tool	What you type in	What comes back
Can I eat this? I am holding the package.	Net Carb Calculator	Total carbohydrate, fiber, grams of sugar alcohol, and which sugar alcohol it is	Net carbs for that serving, plus what was removed and why
How much am I supposed to eat in a day?	Keto Macro Calculator	Sex, age, height, weight, activity, goal, and your carb cap	Daily calories with grams of fat, protein, and net carbs
The recipe wants a cup of sugar. Now what?	Sweetener Converter	How much sugar the recipe calls for, in cups, spoons, or grams	The matching amount of nine sweeteners, each with a heat note

The math in all three runs in your browser. Nothing you type is sent anywhere or stored.

How net carbs work, and why the package number is not one

On a US label, total carbohydrate already contains the fiber and the sugar alcohols. Counting net carbs means subtracting back out the parts that do not end up as glucose. Fiber comes out in full. Sugars never come out, because they are already digestible carbohydrate sitting inside the total.

Sugar alcohols are where the arithmetic splits, and it is the part most calculators skip. Erythritol and allulose are absorbed and then excreted largely unchanged, so they come out in full. The others all carry some glycemic load, and maltitol is the outlier: its glycemic index sits around 35, against roughly 9 to 13 for xylitol, sorbitol, and isomalt, and 0 for erythritol. The standard keto adjustment counts half their grams, which is deliberately conservative for the low three and about right for maltitol. Our calculator implements exactly that: full for erythritol and allulose, half for the rest, and half for any blend you cannot identify.

Two label problems follow from this. First, the FDA does not define "net carbs" at all, so any net carb figure printed on a box is the brand's own arithmetic, and brands routinely subtract every sugar alcohol in full to publish a smaller number. Second, the sugar alcohol line is voluntary on a US panel unless the package makes a sugar or sugar alcohol claim, and when it is printed it usually reads as a generic "Sugar Alcohol" total. Naming the specific polyol is only permitted when the product contains exactly one, so any blend shows the generic line by law. The ingredient list is where you find out whether you are looking at erythritol or maltitol, and that single word decides whether you subtract 12 grams or 6.

What a macro target settles, and what it does not

A macro calculator returns four numbers, and they do not carry equal weight. The carb cap is a threshold rather than a target: 20 to 25 grams of net carbs keeps most people in ketosis, and there is no benefit to landing exactly on it. Protein is anchored to your body weight, around 0.8 grams per pound, because protein need scales with your body and not with your calorie total. Fat is whatever calories remain, which is why it looks so large. Only the calorie figure is a real estimate, and it is the shakiest number on the page.

That estimate comes from the Mifflin-St Jeor equation plus an activity multiplier you choose yourself, and the multiplier is where most of the error enters. Sedentary and moderate differ by roughly 30 percent of your daily calories, and almost everyone picks the flattering one. Treat the output as a two to three week experiment: eat to it, watch the scale, and move the calorie number rather than the formula. If you are simply capping carbs and eating when hungry, you can skip this tool entirely and nothing bad happens.

Sweeteners do not swap into a recipe one for one

Granulated erythritol and allulose are roughly 70 percent as sweet as sugar, so a cup of sugar needs about a third more of either. Branded blends are formulated around that gap and measure cup for cup. Stevia and erythritol blends run about three times as sweet, so a cup of sugar becomes about a third of a cup. Pure stevia and monk fruit extracts are hundreds of times sweeter and have no bulk at all, which means they can match the sweetness of a cake and still leave you without the volume and structure the sugar was providing.

Heat behavior matters as much as sweetness. Allulose browns and caramelizes close to sugar, and it browns faster, so drop the oven temperature or shorten the bake. Plain erythritol barely browns, cools on the tongue, and recrystallizes as the bake cools, which is where grainy keto cookies come from. Powdering it, or mixing in allulose, softens both problems. The keto sweeteners guide holds the full ratios and the reasoning; the converter just does the arithmetic on them.

Where to take the numbers next

A net carb figure is only useful once it changes what you cook. For swapping the high-carb part of a dish, the low carb substitutes guide covers flours, thickeners, rice, and pasta with the carb cost of each. The cheese guide ranks cheeses by net carbs per ounce and says which ones melt or fry, and nuts by net carbs does the same for the snack most likely to quietly break a daily cap.

For sweetener practice, low carb desserts is the hub, and two recipes are worth running the converter against first: cheesecake mousse, which is no-bake and forgiving of any sweetener you pick, and panna cotta, where the sweetener dissolves into cream and erythritol's grittiness has nowhere to hide.

Frequently asked questions