Four methods. One page. Find your number and stop guessing.
Not all calorie formulas are created equal. The Quick Method is fast. Mifflin-St Jeor is the clinical standard. Harris-Benedict is the original. Katch-McArdle is the most accurate — if you know your body fat percentage. Use them all and compare.
Most calorie calculators are built for 25-year-olds with fast metabolisms and forgiving margins for error. You're not 25, and the margin isn't as forgiving anymore. Muscle mass changes the math. A slower resting metabolism changes the math. Years of guessing your way through diets that didn't account for either changes the math too.
This calorie calculator for men over 40 runs your numbers four different ways, because no single formula gets it perfectly right for every body. Run two or three and compare. If they land within a couple hundred calories of each other, you've got a real number to work from. Stop guessing and start tracking against something solid.
The fastest way to estimate your maintenance calories. Multiply your bodyweight in pounds by 15. It's not the most precise tool in the box but it's accurate enough to get started and takes about three seconds.
The most widely used formula in clinical nutrition settings. Developed in 1990, it accounts for age, height, weight, and sex to estimate your Basal Metabolic Rate (BMR) — the calories you burn at complete rest. Multiply by your activity level to get your Total Daily Energy Expenditure (TDEE).
The original BMR formula, developed in 1919 and revised in 1984. It uses the same inputs as Mifflin-St Jeor but with different coefficients. Generally produces slightly higher estimates. Useful to compare both and average the results for a more reliable target.
The Katch-McArdle formula requires your body fat percentage. If you don’t have it from a DEXA scan or calipers, use this Navy Method estimator. All you need is a tape measure. Measure at your waist (at the navel), neck (below the Adam’s apple), and your height. Takes 60 seconds.
The most accurate BMR formula available — but only if you know your body fat percentage. Unlike the other formulas, Katch-McArdle calculates from lean body mass rather than total weight. This makes it especially valuable for men who carry significant muscle, where other formulas tend to overestimate calorie needs.
If you don’t have it from a DEXA scan or body fat calipers, use the Navy Method estimator above to get an estimate. Without an accurate body fat percentage this formula will not give you reliable results — use Mifflin-St Jeor or Harris-Benedict instead.
Start with your TDEE from one of the calculators above, then subtract 300 to 500 calories. For most men over 40, that lands somewhere in the 1,800 to 2,400 calorie range depending on size and activity level, but the calculator above gives you your actual number instead of a generic guess.
Katch-McArdle is the most accurate, but only if you know your body fat percentage. If you don't, Mifflin-St Jeor is the clinical standard and the best default. Run both if you can and use the body fat estimator above to get Katch-McArdle into range.
Muscle mass naturally declines with age unless you're actively training to keep it, and muscle burns more calories at rest than fat does. That means your maintenance number is quietly dropping even if your weight and habits haven't changed, which is exactly why generic calculators built for 25-year-olds tend to overestimate what a man in his 40s or 50s actually needs.
Compare at least two. Every formula is an estimate, and Harris-Benedict tends to run a little higher than Mifflin-St Jeor for the same person. If your results land close together, that range is your real number. If they're wildly different, your body fat percentage estimate is probably off, which throws off Katch-McArdle specifically.
Only for Katch-McArdle. The Quick Method, Mifflin-St Jeor, and Harris-Benedict all work from your weight, height, age, and activity level alone. If you don't have a DEXA scan or calipers, use the Navy Method body fat estimator built into this page to get a close-enough number.
These calculators give you the number. The Long Game gives you everything you do with it — protocols, meal plans, recipes, the Klein Method, and the mindset to make it stick.
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