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IV drip rate chart: drops per minute by volume, time and drop factor

1,000 mL over 8 hours is 125 mL/h on a pump. On a gravity set that is 21 gtt/min at 10 gtt/mL, 31 at 15, 42 at 20 and 125 at 60, so a microdrip set drips 6 times as fast as a 10 gtt/mL set for the same order. Read the factor off the tubing package.

Line chart, on a log scale, of the gravity drip rate in whole drops per minute for a 1,000 mL bag run over 2 to 24 hours on four drop factors. 10 gtt/mL, a solid line with circles, from 83 at 2 h to 7 at 24 h; 15 gtt/mL, a dashed line with squares, from 125 at 2 h to 10 at 24 h; 20 gtt/mL, a dotted line with triangles, from 167 at 2 h to 14 at 24 h; 60 gtt/mL, a dash-dot line with diamonds, from 500 at 2 h to 42 at 24 h. A grey vertical dashed line at 8 h marks 125 mL/h, where the four read 21, 31, 42 and 125 gtt/min. The four lines run nearly parallel; rounding to whole drops makes the slow ones step, and the 10 gtt/mL line holds at 8 from 20 to 22 h. Line chart, on a log scale, of the gravity drip rate in whole drops per minute for a 1,000 mL bag run over 2 to 24 hours on four drop factors. 10 gtt/mL, a solid line with circles, from 83 at 2 h to 7 at 24 h; 15 gtt/mL, a dashed line with squares, from 125 at 2 h to 10 at 24 h; 20 gtt/mL, a dotted line with triangles, from 167 at 2 h to 14 at 24 h; 60 gtt/mL, a dash-dot line with diamonds, from 500 at 2 h to 42 at 24 h. A grey vertical dashed line at 8 h marks 125 mL/h, where the four read 21, 31, 42 and 125 gtt/min. The four lines run nearly parallel; rounding to whole drops makes the slow ones step, and the 10 gtt/mL line holds at 8 from 20 to 22 h.
Drops per minute for 1,000 mL by infusion time on a log scale. Before rounding the four lines run parallel, a fixed ratio apart; whole drops make the slow lines step. Every plotted point is a row of the table. Image © ScienceQuest, CC BY 4.0: free to reuse with credit and a link to this page, as the image licence explains.

Drip rates for 17 common orders

Pump rate in mL/h and gravity drip rate in whole drops per minute on 10, 15, 20 and 60 gtt/mL sets, for 17 orders of 1,000, 500, 250, 100 and 50 mL over 15 min to 24 h, one row for each of the 8 rates they come to
Orders (mL/time) Pump Gravity set, gtt/min
Rate mL/h 10 gtt/mL 15 gtt/mL 20 gtt/mL 60 gtt/mL
1,000/4 h, 500/2 h, 250/1 h 250 42 63 83 250
100/30 min, 50/15 min 200 33 50 67 200
1,000/6 h 166.7 28 42 56 167
1,000/8 h, 500/4 h, 250/2 h 125 21 31 42 125
1,000/10 h, 100/1 h, 50/30 min 100 17 25 33 100
1,000/12 h, 500/6 h 83.33 14 21 28 83
500/8 h, 250/4 h 62.5 10 16 21 63
1,000/24 h 41.67 7 10 14 42

On the 60 gtt/mL microdrip set the drip rate equals the pump rate rounded to a whole drop, because 60 drops make a mL and 60 minutes make an hour. Pump rates to four significant figures, as the IV infusion rate calculator prints them.

A 1,000 mL bag over 1 to 24 hours

Pump rate in mL/h and gravity drip rate in whole drops per minute on 10, 15, 20 and 60 gtt/mL sets, for 1,000 mL run over each whole hour from 1 to 24
Time (h) Pump Gravity set, gtt/min
Rate mL/h 10 gtt/mL 15 gtt/mL 20 gtt/mL 60 gtt/mL
1 1,000 167 250 333 1,000
2 500 83 125 167 500
3 333.3 56 83 111 333
4 250 42 63 83 250
5 200 33 50 67 200
6 166.7 28 42 56 167
7 142.9 24 36 48 143
8 125 21 31 42 125
9 111.1 19 28 37 111
10 100 17 25 33 100
11 90.91 15 23 30 91
12 83.33 14 21 28 83
13 76.92 13 19 26 77
14 71.43 12 18 24 71
15 66.67 11 17 22 67
16 62.5 10 16 21 63
17 58.82 10 15 20 59
18 55.56 9 14 19 56
19 52.63 9 13 18 53
20 50 8 13 17 50
21 47.62 8 12 16 48
22 45.45 8 11 15 45
23 43.48 7 11 14 43
24 41.67 7 10 14 42

A 500 mL bag drips as 1,000 mL over twice the time: 500 mL over 8 h is the 16 h row. The chart draws this table from 2 h.

A pump rate as drops per minute

Gravity drip rate in whole drops per minute (gtt/min) for pump rates from 5 to 250 mL/h on 10, 15 and 20 gtt/mL macrodrip sets
Pump rate (mL/h) 10 gtt/mL 15 gtt/mL 20 gtt/mL
5 1 1 2
10 2 3 3
15 3 4 5
20 3 5 7
25 4 6 8
30 5 8 10
35 6 9 12
40 7 10 13
45 8 11 15
50 8 13 17
60 10 15 20
70 12 18 23
75 13 19 25
80 13 20 27
90 15 23 30
100 17 25 33
110 18 28 37
120 20 30 40
125 21 31 42
150 25 38 50
175 29 44 58
200 33 50 67
225 38 56 75
250 42 63 83

Each cell is the pump rate × drop factor ÷ 60, rounded to a whole drop. At 60 gtt/mL the drops per minute equal the pump rate, so the table leaves that column out.

Why the drop counts differ

The drop factor counts how many of a set’s drops make 1 mL, so a 10 gtt/mL set forms drops of 0.1 mL and a 60 gtt/mL microdrip set drops of 0.017 mL. To deliver the same 125 mL/h, the microdrip set drips 6 times as often as the 10 gtt/mL set. Each drip column is the pump rate times the drop factor over 60: a sixth of the mL/h figure at 10 gtt/mL, a quarter at 15 gtt/mL and a third at 20 gtt/mL.

You cannot count a fraction of a drop, so the calculators round to whole drops once, at the end, as Open RN’s section 5.5 does. Half a drop is a bigger share of a slow rate. Of the orders, 3 come to 10.42 gtt/min, set as 10, 4.0 percent slow. At that rate, 250 mL over 4 h at 10 gtt/mL would finish 10 minutes late, 500 mL over 8 h at 10 gtt/mL 20 minutes late and 1,000 mL over 24 h at 15 gtt/mL 60 minutes late.

Read a pump’s 125 mL/h as 125 gtt/min on a 20 gtt/mL set and the bag runs at 375 mL/h, 3 times the order; the two figures match on the 60 gtt/mL set alone. Open RN’s section 23.2 gives the risk of error in gravity infusions as the reason many agencies require a pump.

The formulas

Gravity drip rate [1]
Rgtt/min=V (mL)×DF (gtt/mL)t (min)R_{\text{gtt/min}} = \frac{V\,(\text{mL}) \times \text{DF}\,(\text{gtt/mL})}{t\,(\text{min})}
Pump rate [3]
RmL/h=V (mL)t (h)R_{\text{mL/h}} = \frac{V\,(\text{mL})}{t\,(\text{h})}
Pump rate to drip rate [8]
Rgtt/min=RmL/h×DF60R_{\text{gtt/min}} = \frac{R_{\text{mL/h}} \times \text{DF}}{60}

V is the volume to infuse, DF the drop factor printed on the tubing package and t the infusion time, with 1 h = 60 min (NIST SP 811, table 6). Each drip rate is then rounded to the nearest whole drop.

Where each relation holds

Each formula’s sample, the people it holds for, and where it does not apply
Formula Fitted in Holds for Not for
Drip rate Nothing: the units give V × DF ÷ t, mL × gtt/mL ÷ min Gravity sets, on the drop factor printed on the tubing package A pump, which runs in mL/h. A rate set once and left: OpenStax 13.3 has you recount it every one to two hours, if the tubing is bumped and when the patient returns from another department
Pump rate Nothing: V ÷ t is the definition of a flow rate Infusion pumps, which nurses program in mL/h (Open RN 5.13) Setting a gravity set, which you count in drops per minute
Whole drops Open RN 5.5: a drop cannot be given as a fraction, and its rule for doses rounds a 5 up Setting and counting a gravity rate, rounded once at the end, half up: 30 mL/h at 15 gtt/mL is 7.5, set as 8 Rounding the time or the volume first, or where your course or agency policy sets another rule
Drop factor The set’s drip chamber: 10, 15 or 20 gtt/mL macrodrip and 60 microdrip in sets on sale (BD; FDA device records). Open RN 5.14 also lists 12, but no 12 gtt/mL set appears in FDA records Their usual use, in Open RN 5.14: macrodrip for general IV solutions in adults, microdrip for precise amounts of medication for children and infants Another make’s set: 1,000 mL over 8 h is 21 gtt/min at 10 gtt/mL and 42 at 20. A big bag run fast on microdrip: 1,000 mL over 1 h is 1,000 gtt/min, about 17 drops a second

Calculators and simulators

Sources

  1. Ernstmeyer K, Christman E, editors. Nursing Skills 2e, section 5.14, IV Infusion by Gravity. Open RN, WisTech Open; 2023. https://wtcs.pressbooks.pub/nursingskills/chapter/5-14-iv-infusion-by-gravity/
  2. Ernstmeyer K, Christman E, editors. Nursing Skills 2e, section 5.13, Intravenous Infusions. Open RN, WisTech Open; 2023. https://wtcs.pressbooks.pub/nursingskills/chapter/5-13-intravenous-infusions/
  3. Ernstmeyer K, Christman E, editors. Nursing Skills 2e, section 5.15, IV Infusion by Pump. Open RN, WisTech Open; 2023. https://wtcs.pressbooks.pub/nursingskills/chapter/5-15-iv-infusion-by-pump/
  4. Ernstmeyer K, Christman E, editors. Nursing Skills 2e, section 5.5, Rounding. Open RN, WisTech Open; 2023. https://wtcs.pressbooks.pub/nursingskills/chapter/5-5-rounding/
  5. Ernstmeyer K, Christman E, editors. Nursing Skills 2e, section 23.2, Blood Collection and IV Therapy Basics. Open RN, WisTech Open; 2023. https://wtcs.pressbooks.pub/nursingskills/chapter/23-2-iv-therapy-basics/
  6. BD. Calculating Flow Rates, BD-17095; 2020. https://www.bd.com/content/dam/bd-assets/na/medication-management-solutions/documents/tip-sheet/Calculating-Flow-Rates.pdf
  7. US Food and Drug Administration. Global Unique Device Identification Database, device records in AccessGUDID. https://accessgudid.nlm.nih.gov/
  8. Bowen C, et al. Clinical Nursing Skills, section 13.3, Intravenous Infusion. OpenStax; 2024. https://openstax.org/books/clinical-nursing-skills/pages/13-3-intravenous-infusion
  9. Thompson A, Taylor BN. Guide for the Use of the International System of Units (SI). NIST Special Publication 811, 2008 edition, chapter 5, table 6. https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-5-units-outside-si

The values are facts and free to use; this table’s selection and presentation are © 2026 ScienceQuest.