How to count calories in homemade food: recipe math vs a photo
There are two honest ways to count calories in homemade food: add up every ingredient in the recipe, or estimate the finished plate with a photo. Knowing when to use each one is the whole game.
The two ways to count calories in homemade food
There are really only two ways to count calories in homemade food: add up every ingredient in the recipe and divide by portions, or estimate the finished plate directly, by eye or with a photo scan. Recipe math is more precise and worth the effort for meals you cook on repeat. The photo method is the fallback for everything else: one-off dinners, food someone else made, and any plate where you'll never see the ingredient list.
Here's how to do both properly, including the trap that quietly ruins most people's recipe math: cooked versus raw weight.
Method 1: ingredient-by-ingredient recipe math
This is the most precise way to count calories in homemade food, and it's less painful than it sounds once you've done it twice.
- Weigh every ingredient raw as it goes into the pot. That includes the invisible stuff: a tablespoon of olive oil is about 120 calories, and it's easy to pour two or three without noticing.
- Look up each ingredient's calories using a per-100 g database entry or the package label, and match the entry to the raw weight you measured.
- Add everything up. That's the calorie total for the whole recipe. Cooking won't meaningfully change it, however long the pot simmers.
- Weigh the finished dish. Put the whole pot on the scale and subtract the weight of the empty pot.
- Divide total calories by cooked weight to get calories per gram. Then weigh your serving and multiply. A 2,000-calorie chili that cooks down to 1,600 g is 1.25 calories per gram, so a 400 g bowl is 500 calories, every time.
The cooked-vs-raw weight trap
Cooking barely changes calories, but it changes weight a lot. Rice soaks up water and gets much heavier, pasta more than doubles, and meat does the opposite, losing water in the pan. So "100 g of chicken breast" means a different amount of food depending on whether you mean raw or cooked, and databases list both, often without making it obvious. The rule: match the database entry to the moment you weighed the food. The whole-pot method above sidesteps the problem, because you lock in calories from raw weights and then only divide by the cooked total.
Tip: write down the calories-per-gram number the first time you make a recipe ("mom's lasagna: 1.9 cal/g"). From then on, counting calories in that dish is a ten-second weigh-and-multiply. No math, no lookups.
Method 2: snap a photo of the finished plate
Recipe math has one requirement you can't always meet: knowing what went in. If you didn't cook the meal, or you cooked it with untracked splashes of oil and "some" cheese, the honest alternative is estimating the finished plate, and photo scanning makes that much faster than guessing. You take a picture, the app names the foods on the plate, estimates portion sizes and returns calories and macros you can adjust.
Be realistic about precision. Photo estimates do best on foods you can see clearly and worst on mixed and layered dishes, where the camera can't see inside. That's less exact than a food scale, but for a meal you'd otherwise log as a wild guess, or not at all, it's a real upgrade. We cover how the technology works in our guide to counting calories from a picture.
When someone else cooked: family dinners, potlucks and meal trains
You can't ask grandma for gram weights, and you shouldn't bring a food scale to a potluck. For these meals, use a three-part approach:
- Photo-scan or eyeball the plate the same way you'd handle a restaurant meal. The tactics in our guide to tracking calories when eating out apply almost unchanged to someone else's kitchen.
- Ask one casual question. "Is there butter in this?" or "cream or milk?" changes an estimate more than anything else, and nobody finds it strange.
- Round up on fat, not volume. Oil and butter are easy to under-count, even for the cook. Assume a generous hand unless you watched them cook.
And keep perspective: one imperfectly logged family dinner barely moves a week's total. Log a reasonable number and move on. Consistency beats precision.
Logging a homemade plate with Foodify
Foodify, our AI calorie counter for iPhone, is built around exactly this problem. Point the camera at your plate: a single food is recognized right on your iPhone, and for a plate with several foods (the chicken, the rice, the roasted vegetables) Foodify's AI estimates a portion for each. Every result is editable before you save it, which matters most for homemade food: if the scan reads your casserole as a smaller serving than you know you took, you change the amount and the calories update.
Foodify is free to download, and Foodify Pro is required to use the app. Pro includes the photo and plate scans and Foodi, the AI coach: a chat where you can send a photo or describe a tricky dish ("lentil curry made with coconut milk, about two cups") and ask follow-up questions. It also includes personalized meal plans and weekly reports. The yearly plan starts with a 3-day free trial.
The dishes everyone struggles with: soups, curries and hidden butter
Some homemade dishes are hard for AI, hard for databases and hard for people, for the same reason: the ingredients are dissolved, submerged or invisible.
- Soups and stews: the liquid hides what's in them, and a "bowl" can vary a lot. Fix: use the whole-pot method once for your own recipes, and for anyone else's, log a similar database entry and adjust the portion honestly.
- Curries and cream sauces: the calories come mostly from the fat in the sauce (coconut milk, cream, ghee), not the visible protein. When in doubt, assume the richer version.
- Hidden butter: mashed potatoes, sautéed vegetables and finished steaks often carry a tablespoon or two of butter, about 100 calories each. If it tastes glossy and delicious, it probably does.
For any dish in this group, treat the first log as a draft: pick your best estimate, then refine it the next time you make or eat the dish. For more scale-free tactics, see our guide to counting calories without weighing food.
Batch cooking: log the recipe once, reuse the portion
Here's where the two methods combine into the laziest accurate system there is. For anything you batch-cook (chili, curry, soup, lasagna), do the full recipe math once, then save the result. Every future serving is just a portion of a known dish: no lookups, no re-scanning, no guessing.
In Foodify, that lives in your saved meals. Log the dish once, save it, and next Tuesday's leftover bowl takes one tap, with the portion still adjustable if tonight's serving is bigger.
FAQ
Should I weigh food raw or cooked when counting calories?
Either works. The trap is mixing them. If you weigh raw, use a raw database entry; if you weigh cooked, use a cooked entry. For whole recipes, the cleanest approach is to weigh ingredients raw, total the calories, then divide by the cooked weight of the finished dish to get calories per gram.
Do calories change when food is cooked?
Not in a way that matters for everyday tracking. Cooking changes water content, which changes weight, but the calories stay in the food, plus whatever fat you added to the pan.
How do I count calories in a meal someone else cooked?
Estimate the finished plate: photo-scan it or match it to a similar database entry, ask what fat it was cooked in if you can, and round the fat up rather than down. One estimated meal barely moves a weekly total, so don't let precision worries stop you from logging it.
How accurate is counting calories in homemade food?
Full recipe math with a food scale is about as precise as home calorie counting gets. Photo and eyeball estimates are rougher, especially on mixed dishes, but still useful for keeping a weekly average on track, particularly when you correct the portions you know better.