How fast can I safely lose weight?

A common guideline is up to about 1% of your bodyweight per week. Leaner you get, the slower you should go to protect muscle. Faster is possible short-term but tends to cost lean mass and rebound, this tool flags anything past that band.

Why does the plan look slower than I hoped?

Because the math is honest. Reaching a big goal in a short window can require a deficit that isn’t safe or sustainable. We’d rather show you a realistic date than a number that leads to burnout and regain. Extend the timeline and the daily target eases.

What is metabolic adaptation?

As you diet, your body burns slightly less energy, so a fixed deficit produces smaller losses over time. It’s why progress stalls and why planned maintenance breaks help. Treat the projected date as a plan to revisit, not a fixed contract.

← Todas las calculadoras

Calculadora

Weight Goal & Deficit Planner

Find the daily deficit or surplus to reach a goal weight by a target date, with an honest feasibility check against safe limits. Free, no signup.

Peso actual

Peso objetivo

Ritmo semanal (kg/sem)En torno al 1 % del peso corporal por semana es seguro. Ir más rápido suele costar masa magra.

Tiempo para alcanzar el objetivo16semanas

A 0,5 kg/sem hacen falta unas 16 semanas para perder 8 kg, es decir −550 kcal al día.

Ajuste diario−550 kcal

Ritmo semanal0,5 kg/sem

% del peso corporal/sem0,56 %

Cambio total8 kg · para perder

Sigue tu plan y ajústalo semana a semana: empieza una prueba gratuita de AFITPILOT

Opcional

Enviarme este plan por correo

Te enviaremos este resumen y una guía breve para ajustar tu ritmo cuando el progreso se estanque.

Sin spam. Cancela la suscripción con un clic.

Newsletter gratuita

Ten estos números a mano

Recibe nuestros mejores análisis de entrenamiento y nutrición, y las nuevas calculadoras antes que nadie.

Sobre esta calculadora

This planner connects three things: how much weight you want to change, how fast, and what daily calorie adjustment that implies. Work from a target date and it returns the deficit (or surplus) per day to get there; work from a weekly rate and it projects when you’ll arrive. The important part is the feasibility check. Roughly one kilogram of body mass stores about 7,700 kcal, so a given rate demands a given daily deficit, and past about 1% of your bodyweight per week, that deficit gets large enough to cost muscle, wreck training, and rebound. We flag aggressive plans and refuse to dress up an unsafe one as achievable. A slower, sustainable rate with the occasional maintenance break almost always beats a crash plan on a stopwatch. Treat the timeline as a plan to adjust, not a promise, real rates vary with adherence and metabolic adaptation.

Fuentes

7,700 kcal per kg of body mass; daily adjustment = weekly rate × 7700 / 7. Safe-rate cap ~1% of bodyweight per week (§7.5).

Preguntas frecuentes

How fast can I safely lose weight?
A common guideline is up to about 1% of your bodyweight per week. Leaner you get, the slower you should go to protect muscle. Faster is possible short-term but tends to cost lean mass and rebound, this tool flags anything past that band.
Why does the plan look slower than I hoped?
Because the math is honest. Reaching a big goal in a short window can require a deficit that isn’t safe or sustainable. We’d rather show you a realistic date than a number that leads to burnout and regain. Extend the timeline and the daily target eases.
What is metabolic adaptation?
As you diet, your body burns slightly less energy, so a fixed deficit produces smaller losses over time. It’s why progress stalls and why planned maintenance breaks help. Treat the projected date as a plan to revisit, not a fixed contract.