Calculators

A high anion gap indicates metabolic acidosis as in ketoacidosis in uncontrolled diabetes, in methanol or ethylene glycol poisoning, or in renal failure patients.

A low anion gap is frequently caused by hypoalbuminemia. It also caused by conditions such as increased serum potassium, calcium, or magnesium levels, or caused by medications or toxins such as lithium.

II.2

Blood Level Concentration Calculator

Blood Level Concentration Calculator
Select substance ingested:
Enter amount ingested:	mL
Enter percent solution:	%
Enter body weight:	kg

Estimated blood level concentration is:

Blood level concentration (mg/dL) = [Amount ingested (mL) x (% solution/100) x specific gravity (g/mL)] / [Volume of distribution (L/kg) x body weight (kg)]

Common Formulations*

Solutions	Brands	% Solution	Type
Alcoholic Beverages: Beer	Beck's Beer (Germany)	4.82	Ethanol
	Budweiser (USA)	4.82	Ethanol
	Corona Extra (Mexico)	4.84	Ethanol
	Great Wall (China)	4.6	Ethanol
	Heineken (Holland)	5.17	Ethanol
	Michelob (USA)	4.99	Ethanol
	Miller Genuine Draft (USA)	5.02	Ethanol
	Miller Lite (USA)	4.4	Ethanol
	Tsingtao (China)	4.7	Ethanol

Brandy		40-50	Ethanol
Rum		40-55	Ethanol
Vodka		40	Ethanol
Whisky		40-55	Ethanol
Wines	Dry White	12.2	Ethanol
	Red Rose	12.5	Ethanol

Automobile Antifreezes	Peak/Long Life Antifreeze	90-97	Ethylene Glycol
	Prestone/50/50	45-55	Ethylene Glycol
	Prestone/5/100 Extended Life	80-95	Ethylene Glycol

Automobile Windshield Washer Fluids	Prestone/De-Icer	30-60	Methanol
		3-7	Ethylene Glycol
	Rain X/Winter De-Icer	70-95	Methanol
		5-15	Isopropyl Alcohol

Rubbing Alcohols	Walgreens Ethyl Rubbing Alcohol	70	Ethanol
	CVS 70% Isopropyl Rubbing Alcohol	70	Isopropyl Alcohol

* Sources:

montclair.edu/psychservices/alcoholindrinks.pdf

alcoholcontents.com/beer/beer.htm

econtent.autozone.com:24999/znetcs/msds

II.3

Body Mass Index (BMI) Calculator

Body Mass Index Calculator
Enter weight:	kg	lb
Enter height:	cm	inches

Body mass index =

BMI = [Wt (kg) x 10000] / [Ht (cm)]²

Defining Overweight and Obesity*

	Type	BMI
Adults (≥ 20 years)	Underweight	< 18.5
	Healthy weight	18.5 to 24.9
	Overweight	25 to 29.9
	Obese	≥ 30
Children (2-19 years)	Underweight	< 5th percentile for children of the same age and gender
	Healthy weight	5th percentile to 84.9th percentile
	Overweight	85th to 94.9th percentile
	Obese	≥ 95th percentile

* Sources:

cdc.gov/healthyweight/assessing/bmi/adult_bmi/index.html

cdc.gov/healthyweight/assessing/bmi/childrens_bmi/about_childrens_bmi.html

II.4

Body Surface Area Calculators

II.4.1

Human Body Surface Area Calculator*

Human Body Surface Area Calculator
Enter height:
Enter weight:

Body surface area = m²

* Based on the Mosteller BSA equation:

BSA (m²) = Square root [ht (cm) x wt (kg) / 3600]

BSA is used to calculate a drug's dose based on BSA.

II.4.2

Animal Body Surface Area Calculator

Animal Body Surface Area Calculator
Select species:
Enter weight:

Animal body surface area = m²

Animal BSA is used by veterinarians to determine a drug's dose for dogs and cats.

II.5

Caloric Requirement Calculator (Adult)

Caloric Requirement Calculator
Select gender:
Enter weight:	kg
Enter height:	cm
Enter age:	years
Select activity factor:
Select stress factor:

Basal energy expenditure (BEE) =
Total daily energy expenditure (TDE) =

Based on the Harris-Benedict equations:

For males:

BEE = 66.67 + [13.75 x Weight (kg)] + [ 5 x Height (cm)] - [6.76 x Age (years)]

For females:

BEE = 655.1 + [9.56 x Weight (kg)] + [1.86 x Height (cm)] - [4.68 x Age (years)]

The total daily energy expenditure (TDE) is calculated taken into accounts of activity and stress factors:

TDE = BEE x activity factors x stress factors

Activity factors:

Confined to bed: 1.2

Ambulatory: 1.3

Stress factors:

Surgery: 1.2

Infection: 1.5 (from 1.4 to 1.6)

Trauma: 1.4 (from 1.3 to 1.5)

Burns: 1.8 (from 1.5 to 2.1)

The energy requirements for infants, children, and teenagers are different than those for adults and vary according to age, growth rate, and clinical or metabolic status. They are about 100 kcal/kg/day for infants, 80 to 100 kcal/kg/day for children, and 35 to 60 kcal/kg/day for teenagers.

II.6

Creatinine Clearance Calculators

II.6.1

Adult Creatinine Clearance Calculator*

Adult Creatinine Clearance (Cl_cr) Calculator (18 years and older)
Select gender:
Enter age in years:
Enter body weight in kg:
Enter serum creatinine in mg/dL:

Creatinine clearance (Cl_cr):

* Based on the Cockcroft-Gault equation:

For males:

Cl_cr = [140 - age] x BW / [72 x S_cr]

where age = in years

BW = actual body weight, in kg

S_cr = serum creatinine, in mg/dL

For females:

Cl_cr (mL/min) = 0.85 x Cl_cr of males

For obese patients (see definitions for obesity in BMI Calculator above): use adjusted ideal body weight to calculate Cl_cr:

Adjusted IBW (kg) = IBW + [0.4 x (ABW - IBW)]

where IBW = ideal body weight (see IBW Calculator), in kg

ABW = actual body weight, in kg

II.6.2

Children Creatinine Clearance Calculator*

Children Creatinine Clearance Calculator (1 year to < 18 years)
Enter height in cm:
Enter serum creatinine in mg/dL:

Clcr =

* Based on the Traub and Johnson equation:

Children Cl_cr (mL/min/1.73 m²) = 0.48 x ht (cm) / S_cr (mg/dL)

II.6.3

Infant Creatinine Clearance Calculator

Infant Creatinine Clearance (< 1 year)
Specify birth weight type:
Enter body length in cm:
Enter serum creatinine in mg/dL:

Cl_cr =

Infant Clcr calculator is to be used when an adequate timed specimen cannot be obtained.

Note: This formula may not be accurate for infants:

• younger than 6 months of age

• with severe starvation or muscle wasting

II.7

Ideal Body Weight Calculator

Ideal Body Weight Calculator
Select gender:
Enter age in years:
Enter height in cm:
Enter actual weight in kg:

Your ideal body weight is: kg

Based on the following formulas:

For adults (18 years and older):

Male IBW (kg) = 50 + (2.3 x height in inches over 5 feet)

Female IBW (kg) = 45 + (2.3 x height in inches over 5 feet)

For children (1-17 years):

a) < 5 feet tall:

IBW (kg) = [height (cm)]² x 1.65 / 1000

b) 5 feet and taller:

Male IBW (kg) = 39 + (2.27 x height in inches over 5 feet)

Female IBW (kg) = 42.2 + (2.27 x height in inches over 5 feet)

II.8

Lean Body Weight (LBW) Calculator

Lean Body Weight Calculator
Select gender:
Enter weight:
Enter height:

Lean body weight = or
Lean body weight =

Based on the following formulas:

Male LBW (kg) = [1.10 x Wt (kg)] - [128 x Wt² / [100 x ht (m)]²

Female LBW (kg) = [1.07 x Wt (kg)] - [148 x Wt² / [100 x ht (m)]²

II.9

mg and mEquivalent Calculator

mg and mEq Converter
Enter number:
Convert to:
Enter atomic or molecular weight:	g
Enter number of valence:

Number =

Based on the following formulas:

mEq = (mg x Valence) / (Atomic formula or molecular weight)

mg = mEq x (Atomic formula or molecular weight) / Valence

Valences and Equivalent Weight for Some Important Ions

Ion	Formula	Valence	Atomic Wt	Equivalent Wt*
Aluminum	Al⁺⁺⁺	3	27	9
Ammonium	NH4⁺	1	18	18
Calcium	Ca⁺⁺	2	40	20
Ferric	Fe⁺⁺⁺	3	56	18.7
Ferrous	Fe⁺⁺	2	56	28
Lithium	Li⁺	1	7	7
Magnesium	Mg⁺⁺	2	24	12
Potassium	K⁺	1	39	39
Sodium	Na⁺	1	23	23
Acetate	C₂H₃O₂^-	1	59	59
Bicarbonate	HCO₃^-	1	61	61
Carbonate	CO₃^--	2	60	30
Chloride	Cl^-	1	35.5	35.5
Citrate	C₆H₅O₇^---	3	189	63
Gluconate	C₆H₁₁O₇^-	1	195	195
Lactate	C₃H₅O₃^-	1	89	89
Phosphate	H₂PO₄^-	1	97	97
	HPO₄^--	2	96	48
Sulfate	SO₄^--	2	96	48

* Equivalent Wt = Atomic Wt / Valence

Example: 2 mEq of KCl (MW = 74.5, Valence = 1) = 149 mg

II.10

mg and mMoles Calculator

mg and mMoles Converter
Enter number:
Convert to:
Enter molecular weight:	g

Number =

Based on the formula:

mMoles = mg / (molecular weight (g) x 1000)

mg = mMoles x (molecular weight (g) x 1000)

II.11

Osmol Gap Calculator

Osmol Gap Calculator
Enter serum sodium Na⁺:	mmol/L (mEq/L)
Enter serum glucose:	mg/dL
Enter serum BUN:	mg/dL
Enter measured osmolality:	mOsm/kg

Calculated osmolarity =
Osmol gap =

Calculated osmolarity = [2 x Na⁺] + glucose/18 + BUN/2.8

where:

Calculated osmolarity = mOsm/L

Na⁺ = mmol/L

glucose = mg/dL

Blood urea nitrogen (BUN) = mg/dL

Osmol gap = Measured osmolality - Calculated osmolarity

0 to +10: Normal osmol gap

>10: Abnormal

<0: Probable lab or calculation error

Drugs Causing Osmolar Gap:

Ethanol

Ethylene glycol

Glycerol

Isopropanol (acetone)

Mannitol

Methanol

Sorbitol

II.12

Water Requirement Calculator

Water Requirement Calculator
Enter age in months:	months
Enter weight in kg:	kg

Daily water requirement is:

The approximate daily water requirement calculations are based on the following estimations:

Based on age:

Neonates: 120 mL/kg/day (from 120 to 180 mL/kg/day)

1 to 12 months: 150 mL/kg/day (maximum 200 mL)

Based on weight:

< 10 kg: 100 mL/kg/day

10 to 20 kg: 1000 mL + (50 mL/kg/day for weight over 10 kg)

> 20 kg: 1500 mL + (20 mL/kg/day for weight over 20 kg)

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All calculator information provided by the DrugInformation.com is for educational purposes only. This information should not be used for the diagnosis or treatment of any health problem or disease and IS NOT INTENDED TO REPLACE CLINICAL JUDGMENT OR GUIDE INDIVIDUAL PATIENT CARE IN ANY MANNER.

Rev 8/11 c