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.
Qp/Qs ratio calculator
Saturations of 98, 70, 99 and 85% give a Qp/Qs of 2: the lungs receive twice the systemic flow, a left-to-right shunt.
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qSOFA calculator
24 breaths a minute, a systolic pressure of 95 mmHg and new confusion give a qSOFA of 3 out of 3. Each finding adds one point, and 2 or more is a prompt to look…
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QTc calculator
A QT of 400 ms at 80 beats per minute corrects to a QTc just under 462 ms with Bazett's formula, while at 60 beats per minute it stays at 400 ms.
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Quarantine activity calculator
A last exposure on 1 March 2026 with a 14-day quarantine gives a release date of 15 March 2026. Enter the exposure date and the number of days your rules…
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Radiation dose calculator
An absorbed dose of 0.002 Gy to the lung from photons, with weighting factors of 1 and 0.12, gives an effective dose of 0.00024 Sv.
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RBC indices calculator
A hemoglobin of 15 g/dL, a hematocrit of 45% and a red cell count of 5 give an MCV of 90 fL and an MCH of 30 pg, plus the MCHC.
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RCRI calculator
High-risk surgery plus a history of ischemic heart disease gives an RCRI of 2: risk class III, with a 6.6% rate of major cardiac events in Lee's original study.
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Relative fat mass calculator
A man 178 cm tall with an 86 cm waist comes out at 22.6 % body fat on the relative fat mass formula.
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REM sleep calculator
Plan 480 minutes of sleep and expect about 116 minutes of REM across 5 complete cycles, roughly 24 % of the night.
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Corrected reticulocyte count
With 4.5 % reticulocytes and a hematocrit of 30, the corrected reticulocyte count is 3 %. The observed share is scaled by the patient's hematocrit over a normal…
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Reverse due date calculator
A due date of 15 October 2026 points to an estimated conception date of 22 January 2026, 266 days earlier.
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Revised Geneva score
A 70-year-old with a heart rate of 80 and pain in one leg scores 7 points, an intermediate probability of pulmonary embolism.
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Revised Trauma Score calculator
Glasgow 15, systolic pressure 120 mmHg and 16 breaths per minute give the maximum Revised Trauma Score of 7.8408.
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Type 2 diabetes risk score
A 52-year-old man with a BMI of 28.4, a 96 cm waist, little daily exercise, no daily vegetables, blood pressure pills and a parent with diabetes scores 16…
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RSBI calculator
20 breaths a minute of 0.4 litres each give a rapid shallow breathing index of 50, below the commonly taught cutoff of 105.
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RMR calculator
A 30-year-old man weighing 80 kg at 180 cm burns about 1780 kcal a day at rest, by the Mifflin-St Jeor equation.
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SAAG calculator
Serum albumin of 3.5 g/dL minus ascitic albumin of 1.2 g/dL gives a SAAG of 2.3, above the 1.1 cutoff, so portal hypertension is likely.
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SAPS II calculator
A 65-year-old medical ICU admission with normal vital signs and lab values scores 18 SAPS II points, a predicted hospital mortality of about 3 %.
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SCORAD calculator
20 % affected skin, intensity signs adding up to 8, and itch and sleep loss scores of 6 and 4 give a SCORAD of 42, in the moderate band.
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Sepsis screen - SIRS plus mentation criteria and flag, free
A temperature of 39.2 °C, pulse 110, 24 breaths a minute, white cells at 16 and a Glasgow score of 13 meet all 5 criteria and raise the sepsis flag, which needs…
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Simple daily calorie intake
A sedentary 30-year-old man of 80 kg and 180 cm needs about 2136 kcal a day to keep his weight steady: a basal rate of 1780 kcal times an activity factor of…
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Skinfold body fat calculator
A 30-year-old man whose seven skinfolds add up to 91 mm has a body density of 1.068323 and 13.34 % body fat by the Jackson-Pollock seven-site method.
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Sleep cycle calculator
To wake at 07:00 at the end of a cycle, go to bed at 23:15 for five 90-minute cycles or at 21:45 for six, allowing 15 minutes to fall asleep.
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Sleep time calculator
Start from the clock you already know, your alarm or your lights-out, and get times that fall on full 90-minute cycles.
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Smoking recovery
Enter your quit date, how many years you smoked and a reference date to see how much of the extra lung-cancer risk caused by smoking has faded: 20 years smoked…
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SNAP-II neonatal score
Add up the six SNAP-II items from a newborn's worst values in the first 12 hours after admission: mean pressure 25, temperature 35.2 °C, ratio 1.5, pH 7.15 and…
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Sobriety calculator
Enter the first day of your sobriety and today's date to see the time in whole years, months and days: from 15 January 2020 to 25 July 2026 is 6 years, 6 months…
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Social distancing calculator
Enter the usable floor area and the required distance to get the most people who fit while keeping that gap: 100 square metres at 2 metres gives each person 4…
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Sodium change calculator
See how far serum sodium should move after one litre of fluid: with sodium at 110, 3% saline (513 mEq/L) and 42 litres of body water, it rises by about 9 mEq/L.
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Corrected sodium calculator
See the sodium a patient would have once high blood sugar is accounted for. A measured 130 mmol/L with glucose at 400 mg/dL becomes 134.8 with the Katz factor…
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Sodium correction rate calculator
Divide the planned change in sodium by the hours you have: going from 118 to 126 mEq/L over 24 hours is a third of a mEq/L per hour, or 8 per day.
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Sodium deficit calculator
Estimate the sodium needed to bring serum sodium up to a target: a 70 kg man going from 120 to 140 mEq/L has about 42 litres of body water, so the deficit is…
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Sodium in salt calculator
Turn grams of salt into milligrams of sodium: 5 g of pure table salt, at a sodium share of 0.3934, holds 1967 mg of sodium.
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SOFA score calculator
Grade six organ systems from 0 to 4 and add them up: ratio 250, platelets 80, bilirubin 2.4, mean pressure under 70, Glasgow 14 and creatinine 1.5 give a SOFA…
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Sperm analysis calculator
Compare a semen analysis with the WHO 2021 lower reference limits: 2.5 mL, 45 million per mL, 55% total motility and 8% normal forms are all normal, for a total…
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Standard drink calculator
Turn a real pour into standard drinks from its volume, alcohol percentage and the country you choose.
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Corticosteroid converter
Convert a dose of one systemic corticosteroid into the matching dose of another: 20 mg of prednisone equals 80 mg of hydrocortisone or 0.75 mg of dexamethasone…
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Stillbirth risk calculator
Estimate the chance of stillbirth over the rest of pregnancy from the week, the mother's age and optional risk factors: at 39 weeks and age 28 with none, it is…
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STOP-BANG calculator
Answer eight yes-or-no questions on snoring, tiredness, observed pauses, blood pressure, BMI over 35, age over 50, neck over 40 cm and male sex.
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Stroke volume calculator
Subtract end-systolic from end-diastolic volume to get the blood pumped out in one beat: 120 mL minus 50 mL is a stroke volume of 70 mL, shown with its ejection…
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Sugar intake calculator
Turn your daily calories into a ceiling for added sugar: on 2000 calories at the common 10% guideline, that is 200 calories or 50 g of added sugar, about 12.5…
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Swiss cheese coronavirus
Stack protection layers and see the infection risk that still gets through: a 70% mask, 50% better ventilation and an 80% vaccine leave a 3% residual, because…
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T/E2 ratio calculator
Divide total testosterone by estradiol to get the T/E2 ratio: 500 ng/dL of testosterone with 25 pg/mL of estradiol gives a ratio of 20.
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Tidal volume calculator
A man 170 cm tall has a predicted body weight of 66 kg, so the lung-protective 6 mL per kilogram gives about 396 mL per breath.
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Time of death estimator
A body at 32.5 °C in a room at 18 °C, weighing 70 kg, has been cooling for about seven and a half hours by the Henssge method.
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TIMI STEMI risk score
A 72-year-old with low blood pressure, a fast pulse, Killip class II and anterior ST elevation scores 13 of 14 points, a published 30-day mortality of 35.9%.
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TIMI UA/NSTEMI calculator
Six of the seven yes-or-no criteria give a score of 6, which is high risk, with a 14-day event rate of 40.9%: death, a new heart attack or severe ischemia…
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Tinetti fall risk calculator
Balance points of 11 and gait points of 9 give a Tinetti total of 20 out of 28, which falls in the moderate fall-risk band.
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ACR TI-RADS calculator
A solid, hypoechoic, wider-than-tall nodule with smooth margins and no echogenic foci scores 4 points, TR4: fine-needle aspiration from 1.5 cm, follow-up from…
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tPA dose calculator
A 70 kg adult gets 63 mg of alteplase in total: a 6.3 mg bolus and 56.7 mg infused over 60 minutes, at 0.9 mg per kg with a 90 mg ceiling.
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Tramadol dosage calculator
A 70 kg 40-year-old with normal kidneys gets 75 mg of immediate-release tramadol every 6 hours, up to 300 mg a day, as an educational starting estimate.
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Transferrin saturation calculator
Serum iron of 100 with a TIBC of 300 means 33.33% of transferrin's iron-binding sites are occupied.
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TTKG calculator
Urine potassium 40, serum potassium 3, urine osmolality 400 and serum osmolality 300 give a transtubular potassium gradient of 10.
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Twin pregnancy weight gain calculator
With a pre-pregnancy BMI of 22, the recommended twin weight gain at 20 weeks is 7.11 to 11.07 kg, on the way to 16.8 to 24.5 kg near twin term.
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Twin pregnancy probability
A 28-year-old with one previous pregnancy and no twins in the family has about a 1 in 66 chance of a twin pregnancy.
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Tylenol dosage calculator
A 20 kg child's single acetaminophen dose falls between 200 and 300 mg, using the 10 to 15 mg per kilogram band.
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Tylenol overdose calculator
A 70 kg adult who swallowed 7,000 mg of acetaminophen has taken 100 mg per kilogram: the possible-risk band, below the 150 mg/kg treatment line.
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Urine anion gap calculator
Urine sodium 40, potassium 20 and chloride 80 mEq/L give a urine anion gap of −20, the classic classroom pattern of ammonium being excreted after gut losses.
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Urine output calculator
Collecting 840 mL of urine over 12 hours from a 70 kg patient is exactly 1 mL per kilogram per hour, within the adequate teaching band.
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Urine pregnancy test interpreter
An hCG level of 150 mIU/mL four days after a missed period reads as positive, well above the usual 25 mIU/mL strip cut-off.
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