Has anyone ever used a genral formula to get fat loss calories instead of online calculator?

Riverside's key point there IMO is that any method - calculator, rule of thumb, fitness tracker - just gives you a starting estimate of your calorie needs. It's basing that estimate on what's average for people from research projects who are similar to you with respect to the few data points you tell the thing that's doing the estimating.

Are you average? Experience with calorie tracking and weight change will tell you. Most people are close to average, a few noticeably off high or low, a rare few surprisingly far off. Reasons why a person is non-average may not be obvious.

As a generality, the fewer the data points a reasonably well-founded estimating method has about you, the more likely the estimate is to differ from your personal reality. X calories times body weight uses the least data points.

I will say that any of those X time weight formulas are horrifyingly far off for me. I'd lose around a pound and a half per week at 12 times goal weight, which is way too fast for best health/performance for a woman at 130 pounds and BMI 21-point-something. 14 times bodyweight would be around a pound a week, also faster than I'd choose right now.

But any of these can work as a starting point to be confirmed by a 4-6 week trial period. It's unlikely to have dire consequences during that trial period unless the estimate is so low that you'd notice fast loss, unexplained weakness/fatigue, and other side effects of too-fast loss.

You're so close to your goal that this kind of thing might not even be a big deal: You could probably succeed - though in a less predictable course - by simply examining your routine eating habits, and finding some easy cutbacks in things you know to be higher calorie, like candy, baked goods, filler carbs (pasta, rice, bread, etc.), sweet drinks, creamy dips/sauces/dressings, fried foods.

At your current weight, fast loss probably wouldn't be a great idea: It has the potential to be more muscle-risking than muscle-revealing.

Best wishes!

Yeah, there are a couple of simple formulas people use instead of plugging numbers into an online calculator. One of the most common is multiplying bodyweight by a set range depending on your activity level:

• 12 calories per lb → aggressive fat loss
• 13–14 calories per lb → moderate fat loss
• 15–16 calories per lb → maintenance (for most people)

So for example, if someone weighs 180 lbs and wants fat loss, they’d start around 180 × 12 = ~2,160 calories. From there, you just adjust based on progress after a couple weeks—if weight isn’t moving, you can drop a little, if it’s falling too fast, you bump up.

It’s not perfect, but it’s a good baseline that keeps things simple without overthinking calculators that sometimes give wildly different results.