Weight-Loss Timeline Calculator

From TDEE and goal weight to daily target or projected date

Prepared by the Nutricity editorial teamLast updated:

A weight-loss timeline calculator estimates how long it will take to reach your goal weight, or how many daily calories you need to reach it by a target date, using your TDEE and the 7,700 kcal per kg rule.

Calculator

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How it is calculated

The calculator first estimates your BMR (Mifflin-St Jeor or Harris-Benedict) and TDEE from the same inputs as the TDEE calculator. It then uses the conventional 7,700 kcal ≈ 1 kg rule to convert the weight gap into calories.

In target-date mode it divides the total calorie gap by the number of days to the goal. In rate mode it uses your chosen kg/week to project the date.

How to interpret the result

The result shows your maintenance TDEE, the required daily calorie target, the implied weekly rate and the projected date (or weeks to goal). Use it as a starting point and adjust based on real weight trends.

What to do with your result

This tool pairs naturally with the calorie deficit/surplus and macronutrient calculators. For personalised plans, especially with medical conditions, consult a dietitian or doctor.

Limitations

  • The 7,700 kcal/kg rule is an approximation; real weight change usually slows as the body adapts.
  • It assumes a constant calorie gap, which is hard to maintain day to day.
  • It does not account for changes in muscle vs fat or individual metabolic adaptation.

Related tools

Calorie Deficit / SurplusWeight loss or gain calorie target, built on TDEE
TDEE CalculatorTotal daily energy expenditure and calorie needs
MifflinBasal metabolic rate calculation in case of heavy obesity

Frequently asked questions

How accurate is the projected date?
It is a mathematical projection based on the 7,700 kcal/kg rule. Real progress usually slows slightly over time as metabolism adapts.
Which mode should I use?
Use target-date mode if you have a specific deadline; use rate mode if you prefer to set a sustainable weekly pace.
Can I use this for weight gain?
Yes. Enter a goal weight above your current weight and the calculator will project a daily surplus and timeline.
How long will it take to lose weight?
It depends on how much you want to lose and your daily deficit. With the 7,700 kcal/kg rule, a deficit of about 500 kcal a day is roughly 0.45 kg (1 lb) a week, or about 2 kg (4 lb) a month. It is a projection: real progress usually slows over time.
How many calories should I eat to lose weight by a certain date?
In target-date mode the calculator divides the total calorie gap by the number of days to that date and subtracts it from your TDEE. If the result is a very low target, allow more time: a moderate pace is easier to sustain.
What is the 7,700 kcal per kg rule?
It is a conventional approximation that equates 1 kg of body weight with about 7,700 kcal. It converts a calorie deficit or surplus into kilos, but it ignores water loss and metabolic adaptation, so treat it as a guide.

Sources

  1. Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr. 1958;6(5):542-546.
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