TDEE Calculator

What Is TDEE and Why Mixed Units Matter

TDEE — Total Daily Energy Expenditure — is the full number of calories your body burns across a 24-hour day, combining your resting metabolism with everything from walking to workouts. This calculator lets you enter height and weight in whatever units you're actually used to seeing on your own scale and tape measure — height in feet and inches while weight stays in kilograms, for instance — a combination surprisingly common for people who grew up with imperial height but track weight on a metric scale (or vice versa).

Behind the scenes, everything is converted to a common metric base before the Mifflin-St Jeor formula runs, so mixing units never affects accuracy — it's purely a convenience feature.

How the Calculation Works

The gauge in your results places your TDEE on a visual scale from 1,200 to 3,600+ calories, giving you an immediate sense of where you sit relative to typical adult ranges. The bar chart below it compares five calorie targets side by side — from an aggressive cut to a muscle-building surplus — so you can see the full spread at a glance rather than reading numbers in isolation.

Reading the Weekly Plan Table

Daily calorie targets are useful, but a single day rarely tells the full story — normal eating varies day to day. The weekly table converts each goal into a 7-day total and an estimated weekly weight change, which is often the more meaningful number to track. A 500 calorie daily deficit becomes a 3,500 calorie weekly deficit — roughly half a kilogram of fat loss — and seeing it framed weekly makes the numbers easier to plan meals and grocery shopping around.

Choosing Your Activity Level Honestly

• Sedentary: Desk-based day, minimal structured exercise.
• Light: 1–3 sessions weekly, lower intensity.
• Moderate: 3–5 real training sessions weekly — where most gym-goers land.
• High: 6–7 sessions weekly, or physical job plus regular training.
• Athlete: Competitive training volume or manual labour plus training.

Overselecting activity level is the single most common reason people stall on a "deficit" that's secretly closer to maintenance. When unsure, choose the lower option — you can always eat a bit more once you see how your body actually responds over 2–3 weeks.

Accuracy and Limitations

Mifflin-St Jeor is accurate to within roughly 10% for most adults, which is why the weekly table shows an estimate rather than a guarantee. Muscle mass, hormone levels, sleep quality, and genetics all shift real-world calorie burn beyond what any formula predicts. Published nutrition research continues to rank it as the most reliable general-population BMR equation available, but treat your first result as a starting point to test against 2–3 weeks of real tracking.

TDEE vs Simple Calorie Estimates

A lot of generic "how many calories should I eat" tools online skip the two-step process entirely and just hand you a flat number based on weight alone. That approach ignores height, age, and — critically — activity level, which is exactly why those numbers so often feel wrong in practice. TDEE is more useful precisely because it's built from your actual physiology (BMR) plus your actual lifestyle (activity factor), rather than a one-size-fits-all guess.

This matters most at the extremes. Two 80 kg adults — one a sedentary office worker, one training six days a week — can have TDEEs 700–900 calories apart despite identical body weight. A flat calorie estimate would treat them identically and be badly wrong for at least one of them.

Adjusting TDEE for Real-World Results

Your first calculated TDEE is a hypothesis, not a certainty. The right way to use it is to eat at the suggested target for 2–3 weeks while tracking both food intake and body weight, then compare what actually happened to what the formula predicted.

• Losing faster than expected? Your real TDEE is likely higher than calculated — you can afford to eat a bit more and still hit your target rate.
• Weight not moving at all? Either your real TDEE is lower than calculated, or food logging is under-capturing actual intake — very common, since people typically underestimate what they eat by 20–40% without precise tracking.
• Losing much faster than the plan suggests? Consider eating slightly more to protect muscle mass and keep the process sustainable — very large deficits are hard to maintain and tend to backfire through binge-restrict cycles.

This iterative approach — calculate, test, adjust — is standard practice among coaches and dietitians precisely because no formula can account for every individual variable. The calculator gives you a scientifically grounded starting point; your own tracked data refines it into something personal.

Frequently Asked Questions