Find a target daily calorie amount for a chosen deficit.
Your maintenance calories (TDEE) minus your chosen daily deficit gives a target intake.
Target: Maintenance − deficit
Weekly loss: ≈ Deficit × 7 ÷ 7700
Is 500 kcal/day a safe deficit?
A 500 kcal/day deficit (about 0.5 kg lost per week) is a commonly used, moderate approach. But everyone is different, and very large deficits are usually not recommended without a doctor's guidance.