Lessons · IV infusion time
Dosage calculation
IV infusion time calculation Infusion-time problems tell you the volume and the pump rate and ask how long the bag will last. Divide volume by rate to get decimal hours, then convert the decimal part to minutes to document a completion time.
The formula Time (hr) = Volume (mL) ÷ Rate (mL/hr)
How to solve it Divide the volume (mL) by the rate (mL/hr) to get decimal hours. Keep the whole-number hours. Multiply the decimal part of an hour by 60 to convert it to minutes. Common mistakes Reading the decimal hours as minutes (0.5 hr is 30 min, not 50 min). Forgetting to add the infusion time to the start time when charting a finish time. Safety check: 0.25 hr = 15 min, 0.5 hr = 30 min, 0.75 hr = 45 min. Convert the decimal, do not read it as minutes.
Worked examples
See it solved An IV pump is running 100 mL of 0.9% normal saline at 75 mL/hr.
How long will the infusion take (hours)?
Answer: 1.33 hr
Step-by-step solution 1. Divide the volume by the rate
100 mL ÷ ( 75 mL ÷ 1 hr )
2. Cancel mL and solve for hours
= 100 ÷ 75 hr
= 1.33 hr
3. Convert the decimal hours to hours and minutes
1.33 hr = 1 hr 20 min
= 1 hr 20 min
An IV pump is running 100 mL of 0.9% normal saline at 100 mL/hr.
Volume 100 mL
Rate 100 mL/hr
How long will the infusion take (hours)?
Answer: 1 hr
Step-by-step solution 1. Divide the volume by the rate
100 mL ÷ ( 100 mL ÷ 1 hr )
2. Cancel mL and solve for hours
= 100 ÷ 100 hr
= 1 hr
3. Convert the decimal hours to hours and minutes
1 hr = 1 hr
= 1 hr
An IV pump is running 100 mL of 0.9% normal saline at 75 mL/hr.
How long will the infusion take (hours)?
Answer: 1.33 hr
Step-by-step solution 1. Divide the volume by the rate
100 mL ÷ ( 75 mL ÷ 1 hr )
2. Cancel mL and solve for hours
= 100 ÷ 75 hr
= 1.33 hr
3. Convert the decimal hours to hours and minutes
1.33 hr = 1 hr 20 min
= 1 hr 20 min
Safe number notation Every number on DoseDrill is written the safe way - and here is why it matters:
Always use a leading zero for amounts under 1: write 0.5 mg , never .5 mg . A missing zero is read as 5 - a ten-fold overdose.Never use a trailing zero after a decimal: write 5 mg , never 5.0 mg . A stray zero is read as 50 .Read the full safe-notation guide →
Keep going More worked iv infusion time examples:
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Practice only - never for real medication. DoseDrill generates problems to help nursing students learn dosage calculation. It must never be used to calculate, prepare, or administer medication to an actual patient. Real administration requires an independent double-check, current drug references, and your facility's policy. A wrong dose can harm or kill - always verify with a licensed professional.