Keep in mind that I calculate enough to achieve caloric deficit. Not to reach an exact number.

I also leave the nutrient part on just eating a varied diet, with lots of whole foods.

I personally use MyFitnessPal, weigh the calorie significant food (e.g. the Protein, starches, fat-rich vegetables and fatty sauces) and establish a rough estimate about the calories.

I try to maintain the error an order of magnitude lower than my estimate. That's why I don't bother weighing leafy and "watery" vegetables (e.g. spinach, letucce or cucurbits). Also, I try to keep an eye of sauces like Mayonnaise, but I usually relax on Mustard (I dunno where you live, but mustard here tends to be low-fat by default).

That error can be easily burnt by the casual movement we do in the day.

Some foods I know, eg. oil 9kcal/g, but mostly I just check the label. Every food in the EU has the calories/100g or calories/100ml on the label. If it's not packaged, I look it up it FDDB [1].

[1]: https://fddb.info/db/de/produktgruppen/produkt_verzeichnis/i...

https://cronometer.com this is what nutritionists use.

It tracks not only calories, but also macros and micros.