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Heparin Dose Calculator

Work out heparin dose instantly with clear inputs, formula shown and shareable results.

About Heparin Dose Calculator

Applies the weight-based unfractionated heparin protocol of an 80 units/kg bolus and an 18 units/kg/h infusion, then converts to a pump rate.

Formula

Weight-based heparin

Bolus (units) = weight x units/kg; infusion (units/h) = weight x units/kg/h; pump rate (mL/h) = units per hour / concentration

Worked example

With the default values below, Heparin Dose Calculator returns Loading bolus of 6,400. Change any input above and every figure here is recalculated in your browser.

Inputs used

Body weightaccepts 2–250 kg
80 kg
Bolus doseaccepts 0–100 units/kg
80 units/kg
Infusion rateaccepts 2–30 units/kg/h
18 units/kg/h
Infusion concentrationaccepts 10–1,000 units/mL
100 units/mL

Results

Loading bolus
6,400 units
Infusion rate
1,440 units/h
Pump rate at that concentration
14.40 mL/h

Step by step

  1. 1Values used
  2. 2Weight-based heparin
  3. 3Loading bolus= 6,400 units
  4. 4Infusion rate= 1,440 units/h
  5. 5Pump rate at that concentration= 14.40 mL/h

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.

Frequently Asked Questions

Is the dose the same for every indication?

No. Venous thromboembolism protocols use higher rates than acute coronary syndrome protocols.

How is heparin monitored?

By APTT ratio or anti-Xa activity, typically six hours after starting and after every rate change.

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