Health & fitness
374 health and fitness calculators: body mass index, calories, ideal weight, heart rate zones, pregnancy dates, hydration and training loads. Clear results with the formula behind them, free in your browser. They inform, they do not diagnose.
Female Widmark BAC calculator
Estimate a woman's blood alcohol level with the Widmark formula: 3 standard drinks at 65 kg after 2 hours give about 0.0875%.
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Calories per serving calculator
Divide the calories of a whole recipe by the servings it makes: 1800 calories over six servings is 300 per serving.
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Carb cycling planner
Share out a weekly carb budget across high, medium and low days: 1400 g with three high, two medium and two low days gives 280 g, 186.7 g and 93.3 g, and the…
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Critical power two-point calculator
Two maximal efforts are enough: 300 seconds at 350 W and 1200 seconds at 300 W give a critical power of about 283.33 W and a W′ of 20 kJ.
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DOTS score calculator for powerlifting totals
A man totalling 500 kg at 75 kg of body weight scores 358.711 DOTS. Enter the squat, bench and deadlift total, body weight and sex category to compare lifters…
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Fractional excretion of sodium calculator
Works out what share of filtered sodium ends up in the urine: plasma sodium 140, urine sodium 40, plasma creatinine 2 and urine creatinine 100 give a FENa of…
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Grade-adjusted pace calculator
Converts a hilly running pace into its flat-ground equivalent: a five-minute kilometre on a 5% climb is worth about 3:51 per km on the flat.
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Heart Rate Recovery Ratio Calculator
Divides your peak exercise heart rate by a later recovery reading: 180 bpm at the peak and 120 bpm afterwards give a ratio of 1.5.
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Heart rate reserve calculator
Subtracts resting heart rate from maximum to give the range you train within: a maximum of 190 bpm and a resting rate of 60 bpm leave a reserve of 130 bpm.
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Robergs-Landwehr maximum heart rate calculator
Applies the Robergs-Landwehr equation, 205.8 minus 0.685 times age, to give an age-based maximum pulse: a 40-year-old gets 178.4 bpm.
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Intermittent fasting window calculator
Turns your first meal and a fasting ratio into clock times: start eating at 12:00 on a 16:8 schedule and your window runs 12:00–20:00, with the fast lasting…
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Lactate threshold heart rate estimate
With a maximum heart rate of 190 bpm, the classic 85% rule puts your lactate threshold at 161.5 bpm.
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Macro Split from Calories Calculator
2000 kcal split 30:40:30 gives 150 g of protein, 200 g of carbohydrate and 66.67 g of fat. Enter your calorie target and any three-part ratio, and get the grams…
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Omega-6 to omega-3 ratio calculator
12 g of omega-6 and 2 g of omega-3 in a day make a ratio of 6:1, in the elevated band. Enter your two daily gram totals to get the ratio and a screening label…
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Lombardi one rep max calculator for weight and repetitions
100 kg lifted for 5 reps gives a Lombardi one-rep max of 117.46 kg. Enter the weight and the reps you completed, and get your estimated single-lift maximum in…
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Mayhew One-Rep Max Calculator from Weight and Repetitions
100 kg lifted for 5 reps gives a Mayhew one-rep max of 119.01 kg. Enter the weight and reps of a genuine working set and the exponential Mayhew equation returns…
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Percent VO2max from heart rate calculator
Training at 60% of your heart rate reserve corresponds to about 75.4% of VO2max. Enter your percent of heart rate reserve and get the matching share of maximal…
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Equivalent race times calculator
A 10K in 40:00 is worth about 19:11 over 5K, 3:04:00 for the marathon and 3:40:17 for 50K. Enter one race result to see equivalent times and paces for eight…
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Saturated fat limit calculator
On a 2,000-calorie day, saturated fat should stay below about 22.22 g: 10 % of the calories, divided by the 9 kcal in each gram of fat.
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Serum osmolality calculator
Sodium 140, glucose 90 and BUN 14 give a calculated serum osmolality of 290 mOsm/kg: 280 from sodium, 5 from glucose and 5 from BUN.
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Sinclair Meltzer-Faber masters calculator
A 40-year-old man weighing 81 kg with a 305 kg total gets a Sinclair coefficient of about 1.269 and an age factor of 1.135, which together turn his total into…
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Swim stroke rate calculator
Divide your stroke count by the seconds it took and multiply by 60 to get strokes per minute: 40 strokes in 60 seconds, or 30 in 45, is 40 SPM, one stroke every…
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Time to sober calculator
At a BAC of 0.08% and an elimination rate of 0.015 points per hour, reaching zero takes about 5 hours and 20 minutes.
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Cycling variability index calculator
A ride with a Normalized Power of 250 W and an average power of 220 W has a Variability Index of 1.1364, a moderately variable effort.
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Warm-Up Set Weight Calculator
With a working weight of 100 kg, the default warm-up climbs through 40, 55, 70, 80 and 90 kg before your first heavy set.
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Water intake per calorie calculator
At one millilitre per calorie, a 2,000 kcal day points to 2,000 ml of water, which is 2 litres or about 67.6 US fluid ounces.
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Bishop Score Calculator
Total the five cervical findings behind the Bishop score: 4 cm dilation, 70% effacement, station -1, a soft cervix and an anterior position score 10, which…
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Pediatric BMI z-score calculator
Place a child's BMI on the growth-chart scale: a BMI of 17.2 with reference values L -2, M 16.5 and S 0.08 for that age and sex gives a z-score of almost one…
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Corrected reticulocyte count calculator
A 3.5% reticulocyte count with a hematocrit of 25 against a normal of 45 corrects to about 1.944%.
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Creatinine clearance calculator
A 50-year-old man weighing 70 kg with a serum creatinine of 1 mg/dL has a Cockcroft-Gault creatinine clearance of 87.5 mL/min.
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Due date from CRL ultrasound calculator
A crown-rump length of 32 mm on a scan dated 15 March 2026 puts the pregnancy at 9 weeks and 6 days, with an estimated due date of 12 October 2026.
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FIB-4 liver fibrosis calculator
Combines age, AST, ALT and platelets into the FIB-4 liver fibrosis index: a 52-year-old with AST 40, ALT 35 and platelets of 180 lands between 1.3 and 2.67, the…
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HOMA-IR insulin resistance calculator
Estimates insulin resistance from one fasting blood draw: glucose of 95 mg/dL and insulin of 10 µIU/mL give a HOMA-IR of 2.346.
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IVF transfer due date calculator
Works out the estimated due date from an embryo transfer: a day-5 transfer on 15 March 2026 adds 261 days and lands on 1 December 2026.
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Optimal nap length calculator
Pick a 20-minute nap for a short recharge or a 90-minute nap for a full sleep cycle, and see the exact clock time each one ends.
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QTc Framingham Calculator
A QT of 400 ms at 75 beats per minute becomes a Framingham QTc of 430.8 ms, with an RR interval of 0.8 seconds.
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Wake time after sleep cycles calculator
Going to bed at 22:30 and sleeping 6 full 90-minute cycles means waking at 07:30 the next morning.
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Pregnancy weeks to months converter
27 completed weeks of pregnancy are 6 months and 3 weeks when every month counts as exactly four weeks.
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Heart rate zones from reserve
Turns your resting pulse and maximum heart rate into five training zones: with 60 and 190 bpm, recovery runs from 125 to 138 bpm and the top zone from 177 to…
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Gellish max heart rate calculator
At 40 years old, the Gellish equation puts your maximum heart rate at 179 bpm: 207 minus 0.7 times your age.
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Maffetone 180 aerobic heart rate
At 40 with steady training, the Maffetone 180 formula puts your aerobic ceiling at 140 bpm, with an easy window of 130 to 140.
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Training impulse TRIMP calculator
An hour at 70% of heart-rate reserve gives a man a Banister training impulse of just over 100 units, one number you can add up across a week of sessions.
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Marathon time predictor calculator
A 10 km race run in 40 minutes points to a marathon of about 3:04:00, at 4:22 per kilometre. Enter one shorter race you trust, in kilometres and seconds, and…
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Race pace band calculator
A 10 km goal of 50 minutes becomes ten marks at 5:00 each, and a 3:30:00 marathon becomes an even 4:58.613 per kilometre that lands exactly on 42.195 km.
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Treadmill incline equivalent pace calculator
Running at 10 km/h on a 5% incline costs as much oxygen as 12.25 km/h on flat ground, a 4:54 kilometre or a 7:53 mile.
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Sleep efficiency calculator
Divide the minutes you slept by the minutes you spent in bed: 390 asleep out of 480 in bed gives 81.25% sleep efficiency and 90 minutes awake in bed.
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Pokemon GO egg hatch calculator
A 5 km egg with 1.2 km already walked still needs 3.8 km, and you are 24% of the way there. Enter any egg distance, event eggs included, and plan your next…
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Plasma osmolality calculator
Sodium of 140, glucose of 90 mg/dL and BUN of 14 mg/dL give a calculated plasma osmolality of 290 mOsm/kg.
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Plasma volume
An 80 kg man who is 180 cm tall with a hematocrit of 0.45 has just under 3 litres of plasma, out of a little over 5 litres of blood.
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Positive pregnancy test
An hCG of 50 mIU/mL against a 25 mIU/mL strip reads positive, at twice the kit's threshold. Enter your measured level and the sensitivity printed on the box to…
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Pregnancy due date calculator
A last period on 1 January 2026 with a 28-day cycle gives a due date of 8 October 2026. Longer or shorter cycles move that date by the difference from 28 days…
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Pregnancy test calculator
At 14 days after ovulation, an hCG of 150 mIU/mL gives an estimated pregnancy probability of 100%.
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Pregnancy test at 3 weeks
At 3 weeks from your last period, serum hCG is usually 5 to 50 mIU/mL, so a standard 25 mIU/mL home strip has about a 30% chance of turning positive.
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Prescription refill calculator
30 tablets at one a day, filled on 1 March 2026, last 30 days, so the next refill falls on 31 March.
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Protein deficit calculator
A 70 kg person moving from 1 to 1.6 g of protein per kilo still needs 42 g more. Enter the current level, the target and body weight to get the shortfall in…
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Protein-creatinine ratio calculator
Urine protein of 30 mg/dL with creatinine of 150 mg/dL gives a ratio of 0.2 mg/mg, or 200 mg/g, which falls in the mild proteinuria band.
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PSA density calculator
A PSA of 4 ng/mL in a 40 cm³ prostate gives a PSA density of 0.1, below the commonly cited 0.15 reference.
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PSA doubling time calculator
If PSA rises from 2 to 4 ng/mL in 90 days, it has doubled once, so the doubling time is 90 days, just under 3 months.
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PSI calculator
A 65-year-old man with heart failure, a breathing rate of 32 and a blood urea of 35 mg/dL scores 115 points: risk class IV, with about 9.3% 30-day mortality.
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PVR calculator
With 400 mL in the bladder before voiding, 350 mL passed and 50 mL left behind, the residual ratio is 12.5% and voiding efficiency 87.5%.
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