Deficit sizing
Calorie Deficit Calculator
A deficit is simply the gap between the energy you use and the energy you eat. This calculator shows how large your gap is, how aggressive it looks, and where caution is warranted.
Your information stays on this device. Nothing you type is sent to a server, saved to an account or added to analytics.
Your results
Reading the intensity labels
Up to about 10 per cent below maintenance is a small adjustment. Around 15 per cent is moderate. Around 20 to 25 per cent is a larger adjustment that most people find harder to hold. Beyond 25 per cent, or below your estimated resting energy requirement, we recommend professional guidance rather than a calculator.
For the behavioural side of this, read why weight loss stalls even when nothing has changed.
Suggested next calculators
- Run every number in the all-in-one fitness calculator
One set of inputs, every number: BMI, BMR, maintenance, target and macros.
- Open the bmr calculator
Estimate the energy your body uses at complete rest.
- Open the tdee calculator
Estimate the total energy you use across a normal day.
Relevant guides
- How Many Calories Should I Eat Per Day? Calculate, Test and Adjust Your Starting Target
Learn how to estimate your daily calorie target for maintenance, fat loss or weight gain, why a fixed 500-calorie cut does not suit everyone, and how to calibrate your number over 14 days.
- BMR vs TDEE: What’s the Difference, and Which Number Should You Use?
BMR is the energy your body burns at complete rest; TDEE adds all movement on top. Neither number is your calorie intake target — that requires choosing a goal. This guide explains the difference clearly.
- Is BMI Accurate? What It Measures, What It Misses, and What to Check Next
Understand what BMI actually measures, why it is still used in medicine, its key limitations for athletes and diverse populations, and a practical five-layer framework to interpret your result.