NutriFit calculators
Free tools for nutrition, body composition and laboratory indices. Find formulas, sources and limitations alongside each result.
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Lab tests and metabolic health
Indices derived from blood work: insulin resistance, lipids, kidneys, liver, iron, vitamin D, hormones. Formulas from clinical guidelines with reference ranges.
Diet and lifestyle checklist
An author-written informational checklist: select your current dietary and lifestyle circumstances to see related nutrient topics.
- Current diet and lifestyle circumstances
- Related nutrient topics without scores or diagnosis
- Laboratory assessment information and its limitations
HOMA-IR Calculator: Insulin Resistance Index
HOMA-IR, HOMA-β and QUICKI from fasting glucose and insulin: insulin resistance and beta-cell function with reference ranges and interpretation.
- HOMA-IR, HOMA-β and QUICKI in one calculation
- Units mmol/L ↔ mg/dL, µIU/mL ↔ pmol/L
- Sources and interpretation limits
TyG Index Calculator (Triglycerides × Glucose)
A research index based on fasting triglycerides and glucose, with TyG-BMI and TyG-WC derivatives.
- TyG, TyG-BMI and TyG-WC in one calculation
- No insulin assay — standard chemistry only
- Explicit formula without invented risk categories
Lipid profile: calculated measures
Calculates Friedewald and Sampson LDL, non-HDL, remnant cholesterol and lipid ratios.
- Calculates Friedewald and Sampson LDL, non-HDL, remnant cholesterol and lipid ratios.
- Friedewald: LDL = total cholesterol − HDL − TG/5, all in mg/dL, when TG <400 mg/dL. Sampson (2020) is used when TG ≤800 mg/dL; negative estimates are not shown. AIP = log10(TG/HDL), both in mmol/L.
- LDL targets depend on overall cardiovascular risk. These measures do not establish individual risk, a diagnosis or a need for medicines. Ratios and AIP are shown without universal normality categories.
eGFR Calculator (CKD-EPI 2021)
Estimated GFR by CKD-EPI 2021 (creatinine, optionally cystatin C), Cockcroft–Gault creatinine clearance and KDIGO CKD stage — with µmol/L and mg/dL conversion.
- CKD-EPI 2021 by creatinine and by creatinine + cystatin C
- Cockcroft–Gault creatinine clearance for drug dosing
- G1–G5 filtration category
HbA1c and average glucose conversion
Estimated average glucose over about 2–3 months from laboratory HbA1c, or an approximate reverse estimate.
- Estimated average glucose over about 2–3 months from laboratory HbA1c, or an approximate reverse estimate.
- The ADAG relationship is a population-based estimate, not an exact match for every individual. NGSP/IFCC conversion uses the official master equation.
- A reverse estimate from average glucose does not replace an HbA1c test or establish a diagnosis. Anaemia, altered red-cell lifespan, haemoglobin variants and pregnancy can affect the relationship. Diagnostic conclusions require clinical assessment and usually repeat confirmation.
Lab Unit Converter
Conversion of 33 lab analytes between SI (mmol/L, µmol/L, nmol/L, pmol/L) and conventional units (mg/dL, ng/mL, pg/mL) by molar mass.
- 33 analytes: chemistry, hormones, vitamins, trace elements
- Two-way conversion at report precision
- Factor table with sources
Vitamin D: van Groningen model estimate
25(OH)D in two units and a weight-based research estimate. No automatic treatment schedule.
- Named research formula
- Explicit limits of applicability
- Conversion between nmol/L and ng/mL
Iron Deficiency Calculator: TSAT, Ferritin and Ganzoni Deficit
TSAT = iron / TIBC × 100%. Ganzoni model: weight × (15 − Hb in g/dL) × 2.4 + 500 mg for weight ≥ 35 kg. It is displayed only when both Hb and ferritin are below the selected thresholds.
- TSAT from iron and TIBC or transferrin
- Ferritin threshold adjusted for inflammation (WHO 2020)
- Descriptive biomarker patterns and the Ganzoni model
PhenoAge Biological Age Calculator (Levine)
The Levine 2018 model combines nine biomarkers and chronological age. PhenoAge is an age equivalent of population risk in the NHANES model, not organ age or individual life expectancy. The difference from age is subtraction, not an aging rate or the statistical PhenoAgeAccel residual.
- 9 biomarkers from a standard CBC and chemistry panel
- PhenoAge estimate and difference from chronological age
- Original Levine 2018 coefficients in SI units
FIB-4 and APRI Calculator: Liver Fibrosis Indices
FIB-4 (Sterling 2006) uses age, AST, ALT and platelets. AASLD 2023 thresholds concern the likelihood of advanced fibrosis in metabolic fatty liver disease, not fibrosis staging. Ages 35–65: lower threshold 1.3; over 65: 2.0; upper threshold 2.67. No category is assigned below 35; do not interpret during acute illness. APRI (Wai 2003) and thresholds 0.5/1.5 concern significant fibrosis in chronic hepatitis C and do not automatically transfer to other diseases.
- FIB-4: AASLD 2023
- APRI with an adjustable AST upper limit of normal
- Algorithm: when elastography and a hepatologist are needed
Vermeulen free testosterone estimate
Calculates free and non-SHBG-bound fractions from total testosterone, SHBG and albumin.
- Calculates free and non-SHBG-bound fractions from total testosterone, SHBG and albumin.
- Vermeulen (1999) equilibrium binding model: K_SHBG=10⁹ L/mol, K_Alb=3.6×10⁴ L/mol, albumin molecular weight 69,000 g/mol. Modelled bioavailable testosterone is free plus albumin-bound testosterone.
- This is calculated, not directly measured. No universal normal range is set: interpretation depends on symptoms, age, sex, assay and repeat measurements.
Anion Gap and Delta Ratio Calculator
Anion gap = Na − Cl − HCO₃; albumin adjustment = 0.25 × (40 − albumin in g/L). Delta ratio = (corrected gap − selected reference) / (reference bicarbonate − HCO₃).
- Anion gap from Na, Cl and HCO₃
- Albumin correction per Figge
- Delta ratio for mixed disorders
Albumin-Corrected Calcium Calculator
Corrected calcium = total calcium + 0.02 × (40 − albumin), with calcium in mmol/L and albumin in g/L. This is the simplified Payne equation.
- Payne correction in mmol/L and mg/dL
- Albumin in g/L or g/dL
- Warning when ionized calcium is needed
Fitness and exercise physiology
Strength benchmarks, heart-rate zones, endurance, body composition and anthropometry — the toolkit of a coach and a sports physician.
Circumference-based body composition and BMI
Historical Hodgdon–Beckett (1984) body fat estimate from height and girths. Men: abdomen at the navel and neck; women: natural narrow waist, hips at their widest point and neck. BMI = weight / height².
- Circumference-based body composition and BMI
- Calculation assumptions
- Adjust the parameters
Estimated one-repetition maximum (1RM)
The main result is an author-defined average of Epley and Brzycki. Individual equations and arithmetic percentages of that average are shown below.
- Estimated one-repetition maximum (1RM)
- Calculation assumptions
- Adjust the parameters
Heart rate reserve zones
Target HR = resting HR + fraction × (maximum HR − resting HR). Five bands are selected here: 50–60, 60–70, 70–80, 80–90 and 90–100% of reserve.
- Heart rate reserve zones
- Calculation assumptions
- Adjust the parameters
Field estimates of VO2max
Cooper: distance covered in 12 minutes. Rockport: a fast 1-mile walk (1609.344 m), elapsed time and finishing heart rate; originally tested in healthy adults aged 30–69. Uth: 15.3 × HRmax / HRrest; tested in well-trained men aged 21–51.
- Field estimates of VO2max
- Calculation assumptions
- Adjust the parameters
Fat-free mass index (FFMI)
Fat-free mass = weight × (1 − body fat percentage / 100); FFMI = fat-free mass / height², with height in metres. For men: normalized FFMI = FFMI + 6.3 × (1.8 − height), following the Kouri (1995) abstract.
- Fat-free mass index (FFMI)
- Calculation assumptions
- Adjust the parameters
Energy estimates from fat-free mass
Fat-free mass = weight × (1 − fat / 100). Katch–McArdle: 370 + 21.6 × fat-free mass; Cunningham: 500 + 22 × fat-free mass. Daily Katch estimate multiplies by the selected activity factor.
- Energy estimates from fat-free mass
- Calculation assumptions
- Adjust the parameters
Historical reference body weight equations
Compare Devine, Robinson, Miller and approximate Hamwi for height ≥ 152.4 cm. The four-equation average is author-defined; AdjBW = Devine + 0.4 × (actual weight − Devine), only when actual weight exceeds Devine.
- Historical reference body weight equations
- Calculation assumptions
- Adjust the parameters
Waist indices WHR, WHtR and VAI
WHR = waist / hips; WHtR = waist / height. Measure waist midway between the lowest rib and top of the pelvis after a natural exhalation, and hips at the widest point. VAI additionally uses weight, triglycerides and HDL in mmol/L following Amato (2010).
- Waist indices WHR, WHtR and VAI
- Calculation assumptions
- Adjust the parameters
Estimated sweat loss during exercise
Sweat (L) ≈ pre-weight − post-weight (kg) + drink (L) − urine (L); rate = sweat / duration in hours. Weigh under matching conditions without wet clothing.
- Estimated sweat loss during exercise
- Calculation assumptions
- Adjust the parameters
Casey Butt anthropometric model
Heuristic estimates of mass and girths from height, wrist, ankle and assumed body fat. The original girths describe male bodybuilders at about 8–10% fat. Berkhan: separate reference of height (cm) − 100 kg.
- Casey Butt anthropometric model
- Calculation assumptions
- Adjust the parameters
Powerlifting coefficients: DOTS, Wilks and IPF GL
Enter weigh-in body mass and the total of best successful squat, bench press and deadlift in kilograms. Uses DOTS, classic Wilks and IPF GL 2020 coefficients for classic powerlifting.
- Powerlifting coefficients: DOTS, Wilks and IPF GL
- Calculation assumptions
- Adjust the parameters
Nutrition and dietetics
Energy, macro- and micronutrients, water, salt, fiber, omega-3 and glycemic load — every target with its source.
Estimated total daily energy expenditure (TDEE)
Mifflin–St Jeor estimates resting expenditure. TDEE = that estimate × selected activity factor. −20% and +15% are author-defined deficit and surplus scenarios.
- Estimated total daily energy expenditure (TDEE)
- Calculation assumptions
- Adjust the parameters
Author-defined macro planner
Protein presets: 1.8–2.2 g/kg for loss, 1.4–1.8 for maintenance, 1.8–2.4 for gain; fat 0.8–1.2 g/kg. Uses range midpoints; carbohydrate is the calorie remainder with 4/9/4 kcal/g factors.
- Author-defined macro planner
- Calculation assumptions
- Adjust the parameters
Heuristic daily water estimate
Selected model: 30 mL/kg + 500 mL per hour of activity + 500 mL in heat. An assumed 75% comes from drinks; a glass is 250 mL. No age-related reduction is applied.
- Heuristic daily water estimate
- Calculation assumptions
- Adjust the parameters
Glycemic load of a portion
GL = GI × available carbohydrate in the portion / 100. Enter GI for the specific food and preparation on the glucose = 100 scale, available carbohydrate per 100 g and portion weight. Initial numbers are a demonstration.
- Glycemic load of a portion
- Calculation assumptions
- Adjust the parameters
Protein reference intakes
For healthy adults, the EFSA PRI is 0.83 g/kg/day. ISSN gives 1.4–2.0 g/kg/day for healthy exercising adults; ESPEN suggests 1.0–1.2 for healthy older adults. Amounts use the actual body weight entered. A reference range is not a safety upper limit.
- Protein reference intakes
- Compare the references
- Scope of use
Dietary fibre reference intakes
References are shown separately: EFSA gives 25 g/day for adults; IOM/NASEM gives 14 g/1000 kcal. IOM age and sex AIs: ages 19–50, men 38 g and women 25 g; over 50, 30 and 21 g. The energy calculation does not automatically replace the other references.
- Dietary fibre reference intakes
- Compare the references
- Scope of use
EPA and DHA reference intakes
The EFSA adult AI is 250 mg EPA+DHA per day from food and supplements combined. During pregnancy and lactation, an additional 100–200 mg DHA/day is specified. This is not a fixed EPA:DHA ratio or the total weight of fish oil.
- EPA and DHA reference intakes
- Compare the references
- Scope of use
Sodium and potassium in a daily diet
For adults, WHO recommends less than 2000 mg sodium and at least 3510 mg potassium per day. Molar ratio: (Na, mg / 23) / (K, mg / 39.1). Approximate salt equivalent: sodium, mg × 2.5 / 1000. The ratio is displayed without an individual risk category.
- Sodium and potassium in a daily diet
- Compare the references
- Scope of use
Ethanol and illustrative Widmark estimate
Calculates ethanol amount, ethanol calories and an approximate concentration using a simplified model.
- Calculates ethanol amount, ethanol calories and an approximate concentration using a simplified model.
- Average coefficients do not describe an individual. The model treats the entered amount as one dose and does not model absorption, food or drinking duration.
- The result cannot establish sobriety, a safe driving time or legal compliance. Even a calculated zero does not confirm absence of alcohol.
Caffeine remaining: model estimate
Estimates caffeine remaining now and at bedtime for a chosen elimination half-life.
- Estimates caffeine remaining now and at bedtime for a chosen elimination half-life.
- Half-life varies between people and with pregnancy, illness and medicines. Enter an assumption; 5 hours is not your measured elimination rate.
- The remaining amount does not predict sleep quality. EFSA references of 400 mg/day for healthy adults and 200 mg/day during pregnancy do not guarantee individual safety.
Hall–Chow weight-change scenario
A simplified model with average parameters illustrates weight change after a sustained reduction in baseline energy intake, with unchanged activity.
- A simplified model with average parameters illustrates weight change after a sustained reduction in baseline energy intake, with unchanged activity.
- This is the linearized two-parameter Hall–Chow model (2011), not the full individual NIH Body Weight Planner. It does not predict fat, muscle or an exact plateau date.
- Scenario for adults, excluding pregnancy and breastfeeding. Baseline intake is assumed to maintain weight and the reduction to be sustained; water, medicines, illness and adherence are not modelled. This does not prescribe a calorie deficit.
Lifestyle and prevention
Sleep, caffeine, alcohol, weight forecasts and validated risk screenings — what shapes health between doctor visits.
Author-defined self-rating wheel
Rate your satisfaction with eight areas over the past 14 days from 1 to 10. Overall score = mean × 10; uniformity index = max(0, 100 − 18 × standard deviation), rounded.
- Author-defined self-rating wheel
- Calculation assumptions
- Adjust the parameters
Sleep schedule planner
Bedtime or wake-up options for 7, 8 and 9 hours of sleep, allowing for time to fall asleep.
- Bedtime or wake-up options for 7, 8 and 9 hours of sleep, allowing for time to fall asleep.
- Most adults are advised to sleep 7–9 hours. These are schedule options, not an individual sleep prescription or a sleep-stage prediction.
- Sleep cycles and stages vary during the night. Clock times cannot guarantee waking during REM or an easy awakening.
FINDRISC Diabetes Risk Score
Reference 10-year risk of type 2 diabetes from 8 FINDRISC factors; total 0–26. Percentages refer to the original study population and are not a precise individual probability.
- Reference 10-year risk of type 2 diabetes from 8 FINDRISC factors; total 0–26. Percentages refer to the original study population and are not a precise individual probability.
- Adjust the parameters
- Calculation assumptions
Psychology and eating behavior
Free validated screening questionnaires for depression, anxiety and eating disorders. A score is a reason to talk to a professional, not a diagnosis.
Eating behaviour: modified DEBQ adaptation
33 questions about usual eating behaviour. Three group means are shown without normality categories or diagnosis.
- 33 questions about usual eating behaviour. Three group means are shown without normality categories or diagnosis.
- Emotional group: items 1–13; external: 14–23; restrained: 24–33. Each mean ranges from 1 to 5; item 17 is scored as 6 minus the answer.
- Items have been modified and grouped. This is not a confirmed validated version of the original DEBQ; clinical norms do not apply. Permission to use the original form requires separate confirmation.
Patient Health Questionnaire-9 (PHQ-9 Depression)
Depressive symptom severity over the last 2 weeks: 9 frequency responses scored 0–3; total 0–27.
- Depressive symptom severity over the last 2 weeks: 9 frequency responses scored 0–3; total 0–27.
- Adjust the parameters
- Calculation assumptions
Generalized Anxiety Disorder 7-Item Scale (GAD-7)
Anxiety symptom severity over the last 2 weeks: 7 frequency responses scored 0–3; total 0–21.
- Anxiety symptom severity over the last 2 weeks: 7 frequency responses scored 0–3; total 0–21.
- Adjust the parameters
- Calculation assumptions
Perceived Stress Scale (PSS-10)
Perceived stress over the last month, assessed using the 10 PSS-10 items.
- Perceived stress over the last month, assessed using the 10 PSS-10 items.
- 10 answers from 0 to 4. Items 4, 5, 7 and 8 are scored as 4 minus the answer.
- This informational result does not establish a diagnosis or prescribe treatment. Translated versions are informational adaptations; separate psychometric validation of each translation has not been confirmed.
Insomnia Severity Index (ISI)
Sleep assessment over the last 2 weeks: 7 items with distinct 0–4 scales; total 0–28. Satisfaction, noticeability, worry and impact on daily life have their own responses.
- Sleep assessment over the last 2 weeks: 7 items with distinct 0–4 scales; total 0–28. Satisfaction, noticeability, worry and impact on daily life have their own responses.
- Adjust the parameters
- Calculation assumptions
SCOFF Eating Disorder Screening Questionnaire
An internationally recognized 5-question clinical screening tool designed to identify the risk of eating disorders (anorexia nervosa and bulimia nervosa).
- Rapid, evidence-based screening completed in under 1 minute
- High clinical sensitivity (100%) and specificity (87.5%)
- Positive screen — further assessment is needed
Intuitive Eating Scale-2 (IES-2)
IES-2: 23 statements about eating attitudes and body signals, with four subscales.
- IES-2: 23 statements about eating attitudes and body signals, with four subscales.
- Agreement from 1 to 5. In the grouped author form, items 1, 2, 3, 7, 8, 9 and 10 are scored as 6 minus the answer.
- This informational result does not establish a diagnosis or prescribe treatment. Translated versions are informational adaptations; separate psychometric validation of each translation has not been confirmed.
Yale Food Addiction Scale mYFAS 2.0
mYFAS 2.0: 13 questions about eating problems over the past 12 months.
- mYFAS 2.0: 13 questions about eating problems over the past 12 months.
- Eight frequency options, from never to every day. Each item has its own frequency threshold; yes/no answers are not used.
- This informational result does not establish a diagnosis or prescribe treatment. Translated versions are informational adaptations; separate psychometric validation of each translation has not been confirmed.
Eating behaviour self-assessment
Five SCOFF questions and four author-written questions for reflection on eating behaviour.
- Five SCOFF questions and four author-written questions for reflection on eating behaviour.
- SCOFF is scored using five actual yes/no answers. The other answers are shown directly.
- This informational result does not establish a diagnosis or prescribe treatment. Translated versions are informational adaptations; separate psychometric validation of each translation has not been confirmed.
IQ test
21–22 matrix tasks, nine forms and a numerical IQ estimate. Free, without registration, with sources and an explanation.
- 21–22 original matrix tasks
- Numerical IQ and uncertainty interval
- Nine free forms
This calculation is for reference only and is not medical advice, a diagnosis or a prescription. If you have a medical condition, are pregnant, take medication or have any doubts, discuss the result with a physician or a qualified nutrition professional.
What next
Formula breakdowns, biomarker reference ranges and nutrition articles with cited sources are in the NutriFit knowledge base.
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