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What Daily Calorie Deficit Reaches Your Goal Weight

To lose 30 lb in 12 weeks you need a daily deficit of about 1,250 calories, which means eating roughly 1,150 calories a day if your maintenance is 2,400. That deficit is larger than most people can sustain safely, so a longer timeline or a smaller goal is usually smarter. We use the standard 3,500-calorie-per-pound estimate and your Mifflin-St Jeor maintenance calories.

Results

Visualization

BodyStd provides educational estimates only, using established formulas such as the 3,500-calorie-per-pound rule and the Mifflin-St Jeor equation. These tools do not diagnose any condition and are not medical advice. Weight-loss results vary widely by individual. Consult a physician or registered dietitian before starting any diet, exercise, or weight-loss program.

How It Works

We convert your goal into a total calorie deficit using the long-standing 3,500-calorie-per-pound estimate: total deficit = (current weight - goal weight) x 3,500. Dividing by the number of days gives the required daily deficit. Your suggested intake subtracts that deficit from your maintenance calories. Maintenance is estimated with the Mifflin-St Jeor equation: BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + (5 if male, -161 if female), multiplied by an activity factor (1.2 sedentary to 1.9 very active). The chart applies the weekly loss linearly across the timeline so you can see the path to your goal weight.

What Should You Do?

Aim for a deficit that keeps your intake above 1,200-1,500 calories a day; larger deficits rarely last and raise the risk of muscle loss and rebound. If the calculator shows a deficit above ~1,000 calories, stretch the timeline or pick a smaller first goal. Combine a moderate diet cut with extra activity so neither side has to do all the work. Re-check every few weeks, because your maintenance calories fall as you lose weight and the same deficit shrinks over time.

Frequently Asked Questions

Is 3,500 calories per pound accurate?

It is the standard teaching estimate and works well for rough planning. Real bodies adapt, so treat the result as a starting point, not a guarantee of exact loss.

Why does my suggested intake look so low?

A short timeline forces a big deficit. Lengthen the weeks or lower the goal weight to bring intake into a healthier range.

Do I need to hit the exact deficit every day?

No. Weekly averaging works fine; a few higher days can be balanced by lower days. Consistency over the week matters more than perfection daily.

What if I am already near my goal?

Small remaining gaps still follow the same math but feel slower, because less total fat remains. Keep the deficit modest to protect muscle.

Should women eat fewer calories than men?

On average yes, because BMR differs by body composition and hormones. The calculator accounts for sex in the Mifflin-St Jeor formula.

Can I trust the projected weekly loss?

It is a linear estimate. Early weeks may show faster scale drops from water; later weeks slow as metabolism adapts.