Macro Calculator for Weight Loss
Get the calorie deficit and macro split that strips fat while holding onto your hard-earned muscle.
Losing fat is not just about eating less — it is about eating the right balance of protein, carbs and fat in a controlled calorie deficit. Cut too aggressively or skimp on protein, and you lose muscle alongside fat, wreck your energy, and stall your metabolism.
This calculator is pre-set to a weight-loss goal. It works out your maintenance calories, applies a sensible deficit, and splits the result into a higher-protein macro ratio (35% protein / 40% carbs / 25% fat) designed to preserve muscle and keep you full. Enter your details below to get your daily targets.
Why protein is king when cutting
In a deficit, adequate protein is the difference between losing fat and losing muscle. This calculator sets protein at 35% of calories — typically around 1.8–2.2g per kg of bodyweight — which research consistently links to better muscle retention and greater fullness. Build meals around a protein source first, then add carbs and fats around it.
How big should your deficit be?
The calculator applies a moderate ~20% deficit below your maintenance (TDEE). That generally trends toward roughly 0.5–0.7 kg of fat loss per week — fast enough to see progress, slow enough to protect muscle and adherence. Crash deficits backfire: hunger, muscle loss and rebound eating. If the scale has not moved in 2–3 weeks, drop calories slightly or add movement, rather than slashing further.
Eating for fat loss in New Zealand
Hitting high protein on a budget is very doable here: eggs, canned tuna and salmon, chicken, mince, Greek yoghurt, and milk are cost-effective staples at Pak’nSave, Countdown and New World. Remember NZ labels show energy in kilojoules — divide kJ by 4.184 to get calories. High-volume, low-calorie vegetables (broccoli, courgette, spinach, kūmara in moderation) help you stay full inside your deficit.
Frequently Asked Questions
What are the best macros for weight loss?
A higher-protein split works best for fat loss: roughly 35% protein, 40% carbs and 25% fat, eaten in a moderate calorie deficit. The high protein preserves muscle and keeps you fuller. This calculator applies that ratio automatically.
How much protein do I need to lose weight?
Aim for roughly 1.8–2.2g of protein per kg of bodyweight when cutting. The calculator sets protein to about 35% of your target calories, which lands most people in that range.
Should I cut carbs to lose fat?
Not necessarily. Fat loss is driven by a calorie deficit, not by cutting any single macro. Carbs fuel your training and recovery, so this calculator keeps a moderate carb intake rather than dropping it to zero.
How fast should I lose weight?
About 0.5–0.7 kg per week is a sustainable rate that protects muscle. Faster loss usually means more muscle loss and higher rebound risk. Recalculate your macros after every 5–7 kg lost, since your needs drop as you get lighter.