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Goal Weight Timeline Calculator

Most calorie calculators ask how much you want to lose per week and give a calorie number. This one works in reverse: you pick a daily calorie intake, and it estimates when you may reach your goal weight. It uses your TDEE, the classic 3,500 kcal per pound approximation, and flags unsafe rates, below-floor intakes, and targets that move in the wrong direction.

Reviewed by GetHealthyCalculators Editorial Team · Updated April 14, 2026

Quick Answer

A sustainable fat-loss plan is typically a 300–750 kcal daily deficit below TDEE, yielding roughly 0.5–1.5 lb per week. Use the calculator to see how long your chosen daily intake takes to reach your goal, and adjust if the weekly rate exceeds 2 lb per week.

These results are estimates based on general formulas and are not a substitute for professional medical advice. Consult a healthcare provider before making health decisions.

Fill in your current and goal weights with a daily calorie target to project a timeline.

How the Formula Works

  1. Calculate TDEE from weight, height, age, sex, and activity level (Mifflin-St Jeor).

    TDEE = BMR x Activity Factor

  2. Compute the daily calorie gap between the chosen intake and TDEE.

    Daily Gap = Daily Calories - TDEE

  3. Convert the weekly calorie gap to a rough pound change per week.

    Weekly lb = (Daily Gap x 7) / 3500

  4. Divide the total pounds to lose or gain by the weekly rate to get total weeks.

    Weeks = abs(Total lb) / abs(Weekly lb)

Methodology & Sources

Reviewed and updated April 14, 2026 · Prepared by GetHealthyCalculators Editorial Team

This calculator uses the Mifflin-St Jeor equation for BMR, standard activity multipliers for TDEE, and the 3,500 kcal per pound of body mass approximation. Real-world weight loss asymptotes (Hall 2008) so long-term timelines are approximate. The tool is not a weight-loss prescription and does not account for medications, underlying conditions, or personalized metabolic adaptation.

References

  • Hall KD. What is the required energy deficit per unit weight loss? (2008) · International Journal of Obesity
  • Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals (1990) · American Journal of Clinical Nutrition
  • National Institutes of Health — Dietary Guidelines on safe rates of weight loss · NIH

Limitations

  • The 3,500 kcal per pound rule is an approximation and overestimates loss over long timelines (Hall 2008).
  • This tool does not account for water-weight shifts, hormonal cycles, or adherence variance.
  • Metabolic adaptation slows weight loss over time; real timelines usually take longer than linear models predict.
  • People with medical conditions, on medications affecting metabolism, or with eating-disorder history should work with a clinician.

Frequently Asked Questions

How accurate is the 3,500 kcal per pound rule?
It is a useful short-term approximation and a reasonable educational tool. For multi-month plans, actual loss slows as metabolism adapts and activity tends to decline. A safer framing is to use it as a rough guide for a 4–8 week window, then recalculate.
Why did the calculator flag my target as unsafe?
Typical guardrails: a weekly rate above 2 lb per week, or a daily calorie intake below 1,200 kcal (women) or 1,500 kcal (men) without medical supervision. These thresholds reduce lean-mass loss, metabolic slowdown, and micronutrient shortfalls.
What calorie target produces the best long-term results?
Research on sustainable weight loss suggests that modest deficits of 300–750 kcal per day outperform aggressive deficits over 6–12 months because they preserve adherence, lean mass, and resting metabolic rate.
Can I use this for weight gain?
Yes. Enter a goal weight above your current weight and a daily calorie intake above TDEE. The direction switches to “gain” and the timeline uses the same energy balance math.

Dial in your macro split once your calorie target is set

Macro Calculator

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