TDEE for Cutting — Women Age 18-24, Sedentary

A cutting phase means eating below your total daily energy expenditure (TDEE) so the body covers the shortfall from stored fat. The size of the deficit decides how fast weight comes off — and how sustainable the phase feels. For a 18 to 24-year-old woman who is sedentary — a desk job and little or no planned exercise — the worked example below uses a body weight of 65 kg (143 lb) and a height of 165 cm, and gives a cutting target of 1,200 kcal/day — a deficit of about 498 kcal a day below TDEE. That figure is an estimate built from a published formula, not a personal prescription: your own numbers will differ if your weight, height or daily activity differ from the example.

The worked example is the whole point of this page. Rather than quoting a single number with no working, it shows the Mifflin-St Jeor equation step by step, multiplies the result by the activity factor for a sedentary lifestyle, and then turns the total into a daily calorie target for cutting. Use the same steps with your own measurements, or use the calculator linked below, and you will get a target matched to you rather than to the example person.

Calculate your own TDEE

Your weight, height, age and activity level are almost certainly different from the example above, so run your own numbers with the TDEE calculator. It uses the same Mifflin-St Jeor equation and the same activity multipliers shown on this page, and it also gives cutting, maintenance and bulking targets from a single set of inputs. If you only want the resting figure, the BMR calculator gives that on its own.

Related pages and tools:

The formula: Mifflin-St Jeor (1990)

The Mifflin-St Jeor equation is the most widely validated formula for estimating resting energy expenditure in adults. It was published by Mifflin et al. in the American Journal of Clinical Nutrition in 1990 (Mifflin MD et al., Am J Clin Nutr 1990;51(2):241–247), and it is the equation most calculators and many clinical settings use as a starting point. For women it is:

BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

For men the final term is +5 instead of −161. TDEE is then the BMR multiplied by an activity factor: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active and 1.9 for extremely active. These multipliers are the standard values used with the Mifflin-St Jeor equation.

Working through the example for a 18 to 24-year-old woman at 65 kg and 165 cm:

  • 10 × 65 kg = 650 kcal
  • 6.25 × 165 cm = 1,031 kcal
  • 5 × 21 years = 105 kcal
  • Constant: −161 kcal

So BMR = 650 + 1,031 − 105 − 161 = 1,415 kcal/day. That is the energy the body would use at complete rest, before any movement, digestion or exercise is counted. Multiplying by the sedentary factor of 1.2 gives TDEE = 1,415 × 1.2 = 1,698 kcal/day.

Your targets at a glance

Figure Value
BMR (Mifflin-St Jeor) 1,415 kcal/day
Activity level sedentary (×1.2)
TDEE 1,698 kcal/day
Cutting target 1,200 kcal/day
Safety floor 1,200 kcal/day (women)

The standard 500 kcal deficit would give 1,198 kcal, which is below the 1,200 kcal safety floor — so the cutting target is held at the floor of 1,200 kcal and the deficit is 498 kcal instead. Never eat below the floor without medical supervision.

How activity level changes the number

The same 18 to 24-year-old woman at 65 kg and 165 cm has the same BMR of 1,415 kcal/day whatever the lifestyle — but TDEE moves a lot with activity:

Activity level Multiplier TDEE
Sedentary 1.2 1,698
Lightly Active 1.375 1,946
Moderately Active 1.55 2,194
Very Active 1.725 2,441
Extremely Active 1.9 2,689

The gap between sedentary and extremely active is 991 kcal a day for this person, which is why two people of the same age, sex, weight and height can need very different calorie intakes. It is also why activity level is the input people most often get wrong: be honest about a typical week, not your best week. If you sit most of the day and train three times a week, you are closer to lightly active than moderately active, and using the higher factor inflates the target.

What this number does not tell you

A TDEE estimate is a starting point, not a measurement. The Mifflin-St Jeor equation was validated on population averages, and individual resting metabolic rate varies by roughly ±10% around the prediction because of differences in muscle mass, genetics and health. Two people with identical age, sex, weight and height can have BMRs a few hundred calories apart. The equation also uses total body weight, so it is less accurate for very muscular people (it underestimates) and for people with a high body-fat percentage (it overestimates), because muscle burns more energy at rest than fat does.

Activity multipliers are blunt by design. They compress a whole week of movement, training, work and fidgeting into a single number, and they cannot capture a week that mixes desk days with long hikes, or a job that is physical some days and sedentary on others. Food intake itself also costs energy to digest — the thermic effect of food, roughly 10% of intake — which the multiplier approach folds in approximately rather than measuring. Treat the 1,200 kcal target as a hypothesis: follow it for two to three weeks, watch the weekly weight average, and adjust by 100–200 kcal based on what actually happens.

How to use the 1,200 kcal target

Start at 1,200 kcal a day and hold it for two to three weeks before changing anything. Weigh yourself three to four times a week, first thing in the morning, and compare weekly averages rather than single days — daily weight moves by a kilogram or more with water, glycogen and food volume. If the weekly average is falling by about roughly 0.45 kg per week, the target is working. If it is flat for two full weeks, trim another 100–150 kcal a day, or add a daily walk, rather than slashing calories.

Protein matters more during a cut than at maintenance. Aim for roughly 1.6–2.2 g of protein per kilogram of body weight a day — for the 65 kg example here that is about 104–143 g a day — spread across three to five meals. Protein helps preserve muscle while fat is lost and keeps hunger lower than a low-protein diet at the same calories. Keep resistance training in the programme two to four times a week; the deficit does the fat loss, the training tells the body to keep muscle.

Plan the deficit around real life, not around perfection. A single higher-calorie day does not undo a week of steady eating, and a single low day does not accelerate fat loss in a meaningful way. What matters is the weekly average. If 1,200 kcal feels very low day to day, remember the safety floor: never go below 1,200 kcal a day (women) without medical supervision, and never chase a faster rate than about 0.5–1% of body weight per week.

Frequently asked questions

What is the TDEE for a 18 to 24-year-old woman who is sedentary?

For the worked example on this page — 65 kg, 165 cm, age 21 — BMR is 1,415 kcal/day by Mifflin-St Jeor and TDEE is 1,698 kcal/day at the sedentary multiplier of 1.2. Your own TDEE will differ if your weight, height or activity differ; use the TDEE calculator with your own measurements.

How was the 1,200 kcal cutting target calculated?

It starts from TDEE of 1,698 kcal/day. A 500 kcal daily deficit is the usual cutting starting point, but the result is held at the safety floor of 1,200 kcal/day for women. The target is an estimate, not a prescription.

Does TDEE fall as you get older?

Yes, slowly. In the Mifflin-St Jeor equation the age term subtracts 5 kcal a day for every year of age, so BMR falls by about 50 kcal a decade when weight and height stay the same — and in practice it often falls faster because muscle mass and daily activity tend to decline with age. That is one reason strength training matters more, not less, as the decades pass.

Should I use my current weight or my goal weight in the formula?

Use your current weight. TDEE describes what your body uses now; plugging in a goal weight answers a different question — what you will need once you get there. Recalculate every 5 kg of weight change or so, because a lighter body burns fewer calories and a target set at your old weight gradually becomes a surplus.

Why is my TDEE different from another calculator's?

Different calculators use different equations (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle) and different activity definitions, so results commonly differ by 100–300 kcal. That spread is normal and is another reason to treat any single figure as a starting estimate and adjust from two to three weeks of real weight data.

What should I do if I stop losing weight at 1,200 kcal?

First check the basics: are you tracking everything, including oils, sauces, drinks and weekend meals, and has your activity actually stayed at the sedentary level? If tracking is honest and weight has been flat for two full weeks, reduce intake by 100–150 kcal a day or add 20–30 minutes of daily walking, then reassess after another two weeks. Never drop below 1,200 kcal a day without medical supervision.

Estimates only, not medical advice. Minimum safe intakes: 1,200 kcal/day women, 1,500 kcal/day men — consult a healthcare professional before a very-low-calorie diet.