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Dosage Calcs

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Heparin Drip Rate Calculator

Heparin infusions are ordered in units per hour. Enter the ordered rate and the bag's total units and volume, and the calculator shows the concentration and the mL/hr pump setting, step by step.

Heparin Drip Rate Calculator

Ordered units/hr ÷ Concentration (units/mL) = mL/hr

From the order or assignment, in units per hour. This tool does not supply or check it.

Unit: units/hr

Total units printed on the bag label.

Unit: units

Total volume of the bag in mL.

Unit: mL

Calculated in your browser. Values are not saved or sent anywhere.

Infusion rate

Enter the ordered rate and the bag's total units and volume, then select Calculate.

Example: 1,000 units/hr ÷ 100 units/mL = 10 mL/hr

Educational Use & Safety

Educational and calculation use only. Dosage Calcs performs mathematical calculations using the values you enter. It does not determine whether a medication, dose, route, frequency, concentration, or infusion rate is appropriate or safe for a patient. Always verify medication orders, calculations, product labeling, and applicable clinical or institutional policies before medication administration. When in doubt, consult an appropriate licensed healthcare professional or pharmacist.

Educational Use & Safety

Educational use: You supply the ordered rate and the bag concentration from the order, assignment, or label. This tool does not supply or check a heparin dose, rate, or protocol, and it does not judge whether any value is appropriate or safe. Learn more.

What this calculates

Heparin is a high-alert medication, and infusion orders are written in units per hour rather than mL per hour. To program a pump you need the mL/hr rate, which depends on the concentration of the bag. This page performs that math only: it converts the ordered units/hr into mL/hr using the concentration you enter. It is the same kind of calculation as the IV Flow Rate Calculator, with the concentration step added.

Formula

Concentration (units/mL) = Units in bag ÷ Bag volume (mL)

Rate (mL/hr) = Ordered units/hr ÷ Concentration (units/mL)

The calculator keeps exact fractions and rounds only what it displays. If the result is not a terminating decimal, it is marked as approximate.

Worked examples

These are fictional practice numbers, not recommended rates or concentrations for any patient.

Example 1: a common concentration

Order: 1,000 units/hr. Bag: 25,000 units in 250 mL.

25,000 units ÷ 250 mL = 100 units/mL

1,000 units/hr ÷ 100 units/mL = 10 mL/hr

Example 2: a larger bag

Order: 1,400 units/hr. Bag: 25,000 units in 500 mL.

25,000 units ÷ 500 mL = 50 units/mL

1,400 units/hr ÷ 50 units/mL = 28 mL/hr

Example 3: an approximate result

Order: 1,000 units/hr. Bag: 30,000 units in 500 mL.

30,000 units ÷ 500 mL = 60 units/mL

1,000 units/hr ÷ 60 units/mL ≈ 16.67 mL/hr

Common mistakes

  • Skipping the concentration step and treating units/hr as mL/hr.
  • Using the wrong bag: 25,000 units in 250 mL and in 500 mL give very different mL/hr rates.
  • Dividing concentration by the ordered rate instead of the other way around.
  • Rounding an approximate mL/hr result before finishing the calculation.

What this tool does not do

It does not know any heparin protocol, bolus dose, weight-based rate, or titration rule, and it does not compare your result with any recommended range. A result here only means the arithmetic is correct for the numbers you entered.

FAQ

Why is heparin ordered in units instead of mg?

Heparin is measured by its activity in units, so orders and bag labels use units. This page only converts the ordered units/hr into the mL/hr pump setting for the concentration you enter.

Does it check the rate against a protocol?

No. It only does the division. Comparing a rate with a protocol or titration rule is a clinical step using current orders and policy.

What if the result is a long decimal?

The calculator shows an approximate value marked with ≈ and keeps the exact fraction internally, so no rounding error accumulates.

Sources

Formulas, units, and terminology were checked against these open references. Wording on this page is our own.

All sources · How we build and test calculators