How accurate is the Mifflin-St Jeor formula for women?

Considered the most accurate predictive equation for resting metabolic rate, typically within ±10%. Adjust based on 2-3 weeks of real-world results.

Why does my calorie need change during the luteal phase?

Progesterone elevates BMR by approximately 8-16% in the late luteal phase — roughly 100-200 extra calories per day.

Do I need more protein than the standard recommendation?

For active women, 1.6-2.0 g/kg is optimal. The 0.8 g/kg standard is a minimum, not a body composition target.

Can I take iron and calcium supplements together?

No — calcium inhibits iron absorption. Space by at least 2 hours. Take iron with vitamin C.

How do nutritional needs change in postmenopause?

Prioritise 1200mg calcium + 2000-4000 IU vitamin D3, increase protein to 1.8 g/kg, reduce refined carbs, TDEE decreases ~5%.

What are the best iron food sources for vegetarians?

Lentils, tofu, pumpkin seeds, quinoa, fortified cereals — always combine with vitamin C and avoid tea/coffee with meals.

Medical Notice: This calculator provides general nutritional guidance based on published female physiology research. It is not medical advice. Consult your doctor or registered dietitian before making significant dietary changes, especially if pregnant, breastfeeding, or managing a health condition.

Female Nutrition Calculator

Cycle-phase calorie targets • Iron, calcium & B12 priorities • Life stage adjustments by Coach Aditya

Your Body

Your Stage

Your Goals

Your Body Metrics

Enter your measurements to calculate your baseline calorie needs

Age

Height (cm)

Weight (kg)

Activity Level

Life Stage & Cycle Phase

Your hormonal context changes your nutritional needs significantly

Life Stage

Your Primary Goal

This sets your calorie target and macro ratios

Goal

Trusted by 10,000+ women

Nutrition Science
Built for Female Physiology

Most calorie calculators ignore cycle phases, iron status, and hormonal life stages. This tool accounts for all of it — because women's nutritional needs aren't the same every week.

6Micronutrients tracked

5Cycle phases covered

5Life stages supported

Female Nutrition Calculator: Cycle-Phase Targets & Micronutrient Priorities

Women's nutritional needs change throughout the menstrual cycle, across life stages, and in response to iron status, bone density, and hormonal shifts. A generic calorie calculator built for men — or even a non-gendered tool — misses crucial female-specific requirements: the elevated iron demand during menstruation, the calcium and vitamin D urgency post-menopause, the luteal-phase calorie increase, and the folate requirement in reproductive years.

Mifflin-St Jeor Female Formula

This calculator uses the Mifflin-St Jeor equation for women: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161. Published in the Journal of the American Dietetic Association (1990), this formula shows the highest accuracy for females across multiple independent validation studies. Total Daily Energy Expenditure (TDEE) multiplies BMR by your activity factor, then applies life-stage adjustments.

Cycle Phase Nutrition

Menstruation (Days 1–5): Focus on iron repletion (18–25 mg/day), anti-inflammatory omega-3s, and magnesium for cramp reduction. Avoid excessive caffeine which blocks iron absorption.

Follicular (Days 6–13): Rising estrogen supports carbohydrate metabolism. Emphasise lean protein, complex carbs, and zinc for follicle development.

Ovulation (Day 14): Peak metabolic rate. Antioxidant-rich foods (vitamin E, selenium) support egg health. Zinc and manganese are key.

Luteal (Days 15–28): Progesterone elevates BMR by 100–150 kcal/day. Increase complex carbohydrates, magnesium glycinate (reduces PMS), and vitamin B6 for mood support.

Female Micronutrient Priorities

Iron: Menstruating women need 18 mg/day; those with heavy periods may need 25 mg/day. Pair plant-based iron with vitamin C. Avoid calcium supplements at the same meal — they compete for absorption.

Calcium + Vitamin D: Women under 50 need 1000 mg calcium daily; over 50, 1200 mg. Pair with 2000–4000 IU vitamin D3 and 100 mcg vitamin K2 to direct calcium to bones rather than arteries.

Folate: Critical in reproductive years for neural tube development. 400–600 mcg/day from leafy greens, lentils, and fortified foods.

B12: Especially important for vegetarians and vegans. 2.4 mcg/day minimum; absorption declines with age, making supplementation prudent after 50.

Magnesium: 310–400 mg/day. Magnesium glycinate form preferred for sleep and PMS. Found in dark chocolate, pumpkin seeds, and almonds.

Life Stage Adjustments

Breastfeeding: Add 400–500 kcal/day above maintenance TDEE. Prioritise calcium (1300 mg/day), iodine, choline, and omega-3 DHA for infant brain development.

Perimenopause: Shifting hormones alter fat distribution and insulin sensitivity. Emphasise protein (1.8–2.0 g/kg), resistance training, phytoestrogens (soy, flaxseed), and reduced refined carbohydrate intake.

Postmenopause: TDEE decreases approximately 5% due to reduced estrogen. Calcium and vitamin D become critical. Creatine monohydrate (3–5 g/day) shows emerging evidence for bone density and cognitive function in this population.

Frequently Asked Questions

It is considered the most accurate predictive equation for resting metabolic rate in adults, validated across multiple studies. It typically estimates BMR within ±10% for most women. Factors that can increase error include thyroid conditions, PCOS, and extreme body compositions. Treat the output as a starting point and adjust based on 2–3 weeks of real-world results.

Progesterone elevates basal body temperature and metabolic rate during the luteal phase (days 15–28). Research published in the American Journal of Clinical Nutrition found BMR increases by approximately 8–16% in the late luteal phase compared to the follicular phase — equivalent to roughly 100–200 extra calories per day.

For active women, 1.6–2.0 g of protein per kg of body weight is optimal for muscle retention and hormonal production. The standard 0.8 g/kg recommendation is a minimum to prevent deficiency, not a target for body composition. Higher protein intakes also support satiety, which is relevant during the luteal phase when cravings increase.

No — calcium significantly inhibits non-haem iron absorption when taken together. Space them by at least 2 hours. Take iron with vitamin C (ascorbic acid) to enhance absorption. Take calcium with vitamin D and K2 for optimal bone incorporation. This timing strategy is especially important for vegetarians and vegans who rely on non-haem plant iron.

Post-menopause, estrogen loss reduces bone density protection, increases cardiovascular risk, and shifts fat storage to visceral adipose tissue. Key priorities: 1200 mg calcium + 2000–4000 IU vitamin D3 daily, increase protein to 1.8 g/kg to combat sarcopenia, reduce refined carbohydrates to manage insulin resistance, and consider creatine monohydrate for bone and cognitive benefits. TDEE typically decreases 5% compared to premenopausal TDEE.

Top plant-based iron sources: lentils (3.3 mg/100g), tofu (2.7 mg), spinach (2.7 mg, but oxalates reduce absorption), pumpkin seeds (8.8 mg), quinoa (1.5 mg), and fortified cereals. Always combine with vitamin C — squeeze lemon on dal, eat a tomato with spinach, or have an orange after a lentil meal. Avoid tea and coffee with meals as tannins block iron absorption by 50–90%.