Medical Maths Calculators
Browse calculators for medication doses, tablet quantities, IV drip rates, infusion time, dilutions, reconstitution, BSA, ideal body weight, and creatinine clearance.
Quick choice
Match the calculator to what you have
The units in the order and on the product label usually identify the correct calculation type.
I have a dose in mg and a liquid strength.
Use the mg to mL calculator.
OpenI have a weight-based dose in mg/kg.
Use mg/kg to mL for liquid medicine.
OpenI need the number of tablets to give.
Use a tablet calculator that matches a fixed or weight-based dose.
OpenI need drops per minute or mL per hour.
Use the IV fluids calculators and enter the giving-set drop factor.
OpenI need medication dilution or a final IV concentration check.
Use the medication dilution or final IV concentration calculator.
OpenThe medicine reference requires creatinine clearance.
Open the Cockcroft-Gault creatinine clearance calculator directly.
OpenBrowse by topic
Six focused medical maths topics
Open a topic guide for calculator selection, formulas, worked examples, safety reminders, and FAQs.
Dose Calculations
Convert ordered doses into measurable liquid volumes using concentration, patient weight, or units/mL.
Browse topicTablet & Oral Dosing
Calculate tablets from a fixed mg dose or an optional weight-based mg/kg dose.
Open calculatorIV Fluids & Infusions
Convert between mL/hr, gtt/min, giving-set drop factor, and infusion duration.
Browse topicDilutions & Reconstitution
Work through stock dilution and final IV bag concentration calculations. Use mg to mL for vial withdrawal volume.
Browse topicDosing Body Measures
Calculate body surface area and ideal body weight for medication maths context.
Browse topicRenal Dosing Support
Estimate Cockcroft-Gault creatinine clearance with explicit weight-method selection.
Open calculatorFull directory
All medical maths calculators
Open a calculator directly. Formula cards retain the colour of their dose, tablet, IV, dilution, body measure, or renal topic.
Dose Calculations
Convert ordered doses into measurable liquid volumes using concentration, patient weight, or units/mL.
mg to mL Calculator
Use when the order is in mg and the liquid strength is in mg/mL or mg per X mL.
mL = dose in mg ÷ concentration in mg/mL
mg/kg to mL
Use when a liquid medicine order is written in mg/kg per dose or mg/kg/day and weight is documented in kg or lb.
mL/dose = mg per dose ÷ concentration; daily orders are divided by doses/day
Units to mL Calculator
Use when both the order and product strength are expressed in units.
mL = ordered units ÷ units/mL
Tablet & Oral Dosing
Calculate tablets from a fixed mg dose or an optional weight-based mg/kg dose.
IV Fluids & Infusions
Convert between mL/hr, gtt/min, giving-set drop factor, and infusion duration.
IV Drip Rate
Use when the giving-set drop factor is known and the order provides either mL/hr or total volume and time.
gtt/min = (mL/hr × drop factor) ÷ 60 or (volume × drop factor) ÷ time minutes
gtt/min to mL/hr
Use when drops per minute and the giving-set drop factor are known.
mL/hr = (gtt/min × 60) ÷ drop factor
Infusion Time Calculator
Use when remaining volume and mL/hr are known; add a start time when a clock completion estimate is also needed.
time hours = volume mL ÷ rate mL/hr; clock finish = start time + duration
Dilutions & Reconstitution
Work through stock dilution and final IV bag concentration calculations. Use mg to mL for vial withdrawal volume.
Medication Dilution Calculator
Use for verified medication-dilution arithmetic where the same medicine and matching concentration and volume units are used.
C1 × V1 = C2 × V2
Final IV Concentration
Use after product- or pharmacy-specific reconstitution and transfer values are already verified.
final concentration = amount transferred ÷ verified final total volume
Dosing Body Measures
Calculate body surface area and ideal body weight for medication maths context.
BSA Calculator
Use when a protocol or calculation requires body surface area in m² and a named BSA equation.
Mosteller, Du Bois, Haycock, or Gehan & George
Ideal Body Weight
Use when a medicine reference or protocol specifically requires adult Devine ideal body weight.
IBW = base weight + 2.3 kg per inch over 5 feet
Renal Dosing Support
Estimate Cockcroft-Gault creatinine clearance with explicit weight-method selection.
Calculation safety reminder
MedMaths shows arithmetic. It does not prescribe doses, validate orders, check contraindications, or replace local policy. Confirm the medication order, product strength, units, route, frequency, patient factors, maximum dose limits, compatibility, and independent-check requirements where relevant.
Common calculation types
Medication dose calculations
Use these when a medication order must be converted into a measurable amount, such as mL, tablets, or units.
IV fluid and drip rate calculations
Use these when the question involves mL/hr, drops per minute, drop factor, or the time left for an IV bag.
Medication dilution and IV concentration calculations
Use these when the problem involves stock concentration, final total volume, or a final IV concentration check. Use mg to mL for vial withdrawal volume.
Dosing body measures and renal support
Use these when a medicine calculation or reference specifically requires BSA, ideal body weight, or Cockcroft-Gault creatinine clearance.
Medical maths calculator FAQs
What is MedMaths?
MedMaths is a medical maths calculator website for medication calculations, IV fluid maths, dilutions, body measure calculations, and renal dosing support.
- It is designed to show the formula, calculation steps, and answer clearly.
- The calculators are educational arithmetic tools and do not decide whether a dose is clinically appropriate.
- The name may also be searched as Med Maths, medical maths, or medication maths calculators.
A typical MedMaths calculation is 250 mg ÷ 50 mg/mL = 5 mL.
Which medical maths calculator should I use?
Choose the calculator that matches the units in the question: mg/mL for liquid doses, mg/kg for weight-based doses, gtt/min for drops, and C1V1 for dilution arithmetic.
- If the order is in mg and the label is in mg/mL, use mg to mL.
- If the order is in mg/kg, calculate the total dose from weight first.
- If the problem mentions drop factor, drops per minute, or mL/hr, use an IV calculator.
500 mg ordered with 250 mg tablets uses mg to tablets, not mg to mL.
What calculators are included on MedMaths?
MedMaths includes calculators for dose calculations, tablet dosing, IV fluids, dilutions, BSA, ideal body weight, and creatinine clearance.
- Dose calculators include mg to mL, mg/kg to mL, and units to mL.
- IV calculators include mL/hr to gtt/min, gtt/min to mL/hr, and infusion time.
- Dilution calculators include C1V1=C2V2 and reconstitution to IV bag. Vial withdrawal volume is handled by the mg-to-mL calculator.
There are 12 calculator pages across 6 medical maths topics.
Are MedMaths calculators for nurses and students?
Yes. The calculators are written for medication maths practice, nursing calculation revision, and clinical arithmetic support.
- The pages include formulas, worked examples, FAQs, and practice questions.
- They are useful for checking calculation logic, but they do not replace local medication policy or clinical judgement.
- High-risk medicines should still be checked according to local requirements.
For an IV rate problem, the page shows both the formula and the worked calculation.
Are these calculators medical advice?
No. MedMaths calculators are arithmetic and education tools only.
- They do not prescribe, recommend, or validate medication doses.
- Always check the order, product label, route, patient factors, maximum dose limits, compatibility, and local policy.
- If the answer looks unexpected, stop and recheck the units before using the result.
The calculator can show 20 units ÷ 100 units/mL = 0.2 mL, but it cannot decide whether 20 units is the correct dose.