Cronometer has a built-in keto calculator that sets your macronutrient targets automatically, tracks net carbs, and even syncs with blood ketone meters. It’s one of the most detailed nutrition trackers available for keto because it pulls from research-grade food databases rather than relying solely on user-submitted entries. Here’s how to set it up and get the most out of it.
Set Up the Keto Calculator
The fastest way to get keto-specific targets is through the app’s dedicated keto mode. On mobile, go to More > Targets > Macro & Energy Targets, scroll down to Macro Targets, and select Keto from the options.
Once you’ve selected the keto calculator, you’ll choose from four programs: Rigorous, Moderate, Relaxed, and Custom. The first three automatically set your protein, carb, and fat targets based on standard ketogenic ratios. Rigorous keeps carbs at the lowest level, while Relaxed gives you more room. If none of those fit your needs, Custom lets you edit every value individually, which is useful if you’re following a specific protocol like a higher-protein keto approach or if you’ve calculated your own macros using an external tool.
Your calorie target still matters here. The keto calculator divides your calories into macro percentages, so make sure your overall energy target is set correctly before choosing a keto program. You can adjust this in the same Macro & Energy Targets screen.
Switch to Net Carb Tracking
Cronometer tracks total carbohydrates by default, which isn’t how most keto dieters count their intake. To switch, go to More > Targets > Macro & Energy Targets, tap Show Advanced Settings, scroll to Carbohydrate Settings, and change Track Carbohydrates to Net Carbs.
The default net carb formula is: Total Carbs minus Fiber minus Sugar Alcohols. You can customize which subtractions the app makes. Some people prefer to subtract only fiber, while others also subtract sugar alcohols like erythritol, xylitol, and maltitol. If you’re strict about counting and don’t trust that all sugar alcohols are truly zero-impact (maltitol, for instance, still raises blood sugar more than erythritol), you can remove sugar alcohols from the subtraction so they count toward your carb total.
One detail worth knowing: if you’re logging foods with European or Australian nutrition labels, those labels already list carbohydrates as net carbs with fiber shown separately. Cronometer notes this distinction, so be aware that subtracting fiber again from an already-net-carb label would undercount your intake.
Choose the Right Food Entries
Cronometer’s biggest advantage for keto is its database quality. The app sources nutrition data from the USDA and NCCDB (Nutrition Coordinating Center Food and Nutrient Database), which are research-grade databases with complete micronutrient profiles. When you search for a food, you’ll often see multiple entries from different sources.
Prioritize entries labeled NCCDB or USDA over generic or user-submitted ones. These entries have full nutrient breakdowns, not just calories and macros. That matters on keto because you’re cutting out entire food groups, and tracking micronutrients like magnesium, potassium, and sodium helps you spot deficiencies before they cause symptoms like cramps or fatigue. A user-submitted entry for “cheddar cheese” might have accurate macros but completely blank micronutrient fields, which defeats half the purpose of using Cronometer over a simpler app.
For packaged keto products like protein bars or specialty flours, you may need to scan the barcode or search for the brand name. These entries come from label data and won’t have the same micronutrient completeness, but the macro information is usually accurate enough for carb counting.
Import Recipes Instead of Logging Ingredients Individually
If you cook most of your meals, logging every ingredient separately gets tedious. Cronometer’s recipe importer saves time by pulling ingredients directly from a URL. On mobile, tap Foods > Import Recipe. On the web version, click Foods > Custom Recipes > Import Recipe. Paste the recipe’s URL and Cronometer will build the recipe automatically, pulling each ingredient from its most comprehensive database sources like the USDA and NCCDB.
The importer works with popular recipe sites like AllRecipes and Skinny Taste, among others. After importing, you can edit quantities, swap ingredients, or delete items to match what you actually used. If a recipe site isn’t supported, you can copy and paste the ingredient list as plain text and the app will parse it.
Once saved, the recipe appears as a single item you can log with one tap. It calculates per-serving macros and a full micronutrient profile, so you’ll see exactly how many net carbs are in each portion. This is especially useful for keto staples you make repeatedly, like fat bombs, casseroles, or chaffle batter.
Sync a Blood Ketone Meter
If you test your blood ketones, you can connect a Keto-Mojo meter directly to Cronometer. The app imports blood glucose, blood ketones, and urine ketones automatically. To set it up, go to More > Devices and connect your Keto-Mojo account. Once linked, readings sync to your Cronometer diary so you can see your ketone levels alongside what you ate that day.
If readings aren’t appearing, try disconnecting and reconnecting through the web version at cronometer.com rather than the mobile app. You can also use the Force Sync option under More > Devices > Keto-Mojo to pull in older data you logged before connecting the accounts.
Gold subscribers get access to extended library charts, including a GKI (Glucose-Ketone Index) chart that plots the ratio of your blood glucose to blood ketones over time. This is a more nuanced metric than ketone levels alone, since it accounts for both sides of the metabolic equation. The free tier still lets you log and view individual readings, but the charting and trend analysis requires Gold.
Use the Fasting Timer
Many keto dieters combine their diet with intermittent fasting. Cronometer has a built-in fasting timer under More > Fasting. Tap New Fast to create one, set a duration in hours or days (or toggle “open-ended” if you’re not sure when you’ll break the fast), and choose a start date. The timer appears in your dashboard and diary automatically.
You can set recurring fasts for a consistent schedule. If you do 16:8 every day, for example, create a custom recurrence so the timer starts and stops on its own without manual input. There’s also a helpful safeguard: enable “ask to stop fast when adding food” and the app will prompt you with a warning if you try to log food while a fast is active. This prevents accidental logging errors and gives you a moment to confirm whether you’re actually breaking your fast or just pre-logging a future meal.
Read the Diary View Effectively
Your daily diary is where everything comes together. Each food entry shows its calorie and macro contribution, and your running totals update with every addition. The macro bars at the top show how close you are to your protein, fat, and carb targets for the day. On keto, you’ll want to pay the most attention to the carb bar, since going over your limit is what knocks you out of ketosis.
Below the macros, Cronometer shows a full micronutrient breakdown. Scroll through this regularly during your first few weeks on keto. Common shortfalls for keto dieters include potassium (since you’re eating fewer fruits and starchy vegetables), magnesium, and sodium. If you consistently see these nutrients falling short of their targets, you can adjust your food choices or supplementation accordingly.
Gold subscribers can timestamp individual meals, which is useful for correlating food timing with blood glucose and ketone readings. Free users see their intake as a daily total without time-specific breakdowns.
Tips for Accurate Keto Tracking
- Weigh food in grams. Volume measurements like “1 cup of shredded cheese” vary wildly depending on how tightly you pack it. A kitchen scale removes the guesswork, and Cronometer lets you log in grams for almost every entry.
- Log cooking fats. Butter, olive oil, and coconut oil are keto staples, but they’re also calorie-dense. If you sauté vegetables in two tablespoons of butter, log the butter separately. Cronometer’s recipe entries from database sources won’t always account for added fats.
- Check entries with missing data. If you log a food and notice its fiber content is blank rather than zero, the entry is incomplete. Search for an alternative from the NCCDB or USDA database. An incomplete fiber field means the net carb calculation could be wrong.
- Use the copy function for repetitive days. If you eat similar meals on most days, copy a previous day’s diary instead of re-entering everything. This keeps your tracking consistent and saves time.