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Infusion Time Calculator (mL/hr to hh:mm)

Calculate how long an IV infusion will take to finish when you know the volume (mL) and infusion rate (mL/hr).

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Calculator

How it Works

This calculator estimates how long an infusion will take to finish when you know the total volume (mL) and the infusion rate (mL/hr). It divides volume by rate to get hours, and also displays an hours-and-minutes format for practical planning.

Formula

Time (hours) = Volume (mL) ÷ Infusion rate (mL/hr)

Worked Examples

Example 1: 500 mL at 100 mL/hr

1

Volume = 500 mL, Rate = 100 mL/hr

2

Time = 500 ÷ 100 = 5.00 hours

3

5.00 hours = 5h 0m

Answer: 5h 0m

Example 2: 1000 mL at 250 mL/hr

1

Volume = 1000 mL, Rate = 250 mL/hr

2

Time = 1000 ÷ 250 = 4.00 hours

3

4.00 hours = 4h 0m

Answer: 4h 0m

Example 3: 120 mL at 80 mL/hr

1

Volume = 120 mL, Rate = 80 mL/hr

2

Time = 120 ÷ 80 = 1.50 hours

3

1.50 hours = 1h 30m

Answer: 1h 30m

When This Calculator Is Used

  • •Planning shift timing for IV infusions
  • •Informing patients of expected infusion duration
  • •Scheduling medication administration appointments
  • •Monitoring infusion progress and estimating completion
  • •Coordinating with nursing handover between shifts

Clinical safety note: This is an estimate based on the programmed rate. Actual infusion times vary due to line resistance, positional changes, and gravity effects. Always monitor the IV site and adjust as needed.

Related Calculators

mL/hr to Drip Rate

Convert mL/hr to drops/minute

Volume & Time to mL/hr

Calculate infusion rate from volume and time

Drip Rate to mL/hr

Convert drops/minute to mL/hr

Frequently Asked Questions

Clinical reminder: Always follow local protocols and consult medication information sheets. These examples are for calculation practice only.

References & Sources

This calculator is based on established IV therapy and infusion rate standards from authoritative medical and educational sources.

Manufacturer Reference

Calculating Flow Rates PDF p.1

BD (Becton, Dickinson and Company)

Shows mL/hr calculation from volume and time (rearranges to time = volume ÷ mL/hr).

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Australia Resources

Drug Calculations PDF p.1

Flinders University – Student Learning Support Service

Includes volume/rate/time relationships used for IV infusion calculations.

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Drops per minute (DPM) – Worksheet PDF p.2

University of South Australia (UniSA)

Shows Time (hr) = Volume (mL) ÷ Infusion rate (mL/hr).

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Intravenous Infusion Calculations PDF p.2

University of Southern Queensland (USQ)

Shows time = volume ÷ pump rate relationship in infusion calculations.

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