Enter the mL/hr and drop factor into the calculator to determine the drip rate in gtt/min. Use the Volume & Time tab to calculate from total infusion volume and duration.
mL/hr to gtt/min Conversion Table (Drop factor = 20 gtt/mL)
| mL/hr to gtt/min | gtt/min to mL/hr |
|---|
| 5 mL/hr = 1.67 gtt/min | 5 gtt/min = 15 mL/hr |
| 10 mL/hr = 3.33 gtt/min | 8 gtt/min = 24 mL/hr |
| 15 mL/hr = 5.00 gtt/min | 10 gtt/min = 30 mL/hr |
| 20 mL/hr = 6.67 gtt/min | 12 gtt/min = 36 mL/hr |
| 25 mL/hr = 8.33 gtt/min | 15 gtt/min = 45 mL/hr |
| 30 mL/hr = 10.00 gtt/min | 20 gtt/min = 60 mL/hr |
| 40 mL/hr = 13.33 gtt/min | 25 gtt/min = 75 mL/hr |
| 50 mL/hr = 16.67 gtt/min | 30 gtt/min = 90 mL/hr |
| 60 mL/hr = 20.00 gtt/min | 35 gtt/min = 105 mL/hr |
| 75 mL/hr = 25.00 gtt/min | 40 gtt/min = 120 mL/hr |
| 80 mL/hr = 26.67 gtt/min | 45 gtt/min = 135 mL/hr |
| 100 mL/hr = 33.33 gtt/min | 50 gtt/min = 150 mL/hr |
| 120 mL/hr = 40.00 gtt/min | 55 gtt/min = 165 mL/hr |
| 125 mL/hr = 41.67 gtt/min | 60 gtt/min = 180 mL/hr |
| 150 mL/hr = 50.00 gtt/min | 65 gtt/min = 195 mL/hr |
| 200 mL/hr = 66.67 gtt/min | 70 gtt/min = 210 mL/hr |
| 250 mL/hr = 83.33 gtt/min | 75 gtt/min = 225 mL/hr |
| 300 mL/hr = 100.00 gtt/min | 80 gtt/min = 240 mL/hr |
| 400 mL/hr = 133.33 gtt/min | 100 gtt/min = 300 mL/hr |
| 500 mL/hr = 166.67 gtt/min | 120 gtt/min = 360 mL/hr |
| Formula: gtt/min = (mL/hr x 20) / 60, and mL/hr = (gtt/min x 60) / 20 |
mL/hr to gtt/min Conversion Table (Microdrip, DF = 60 gtt/mL)
| mL/hr to gtt/min | gtt/min to mL/hr |
|---|
| 5 mL/hr = 5 gtt/min | 15 gtt/min = 15 mL/hr |
| 10 mL/hr = 10 gtt/min | 30 gtt/min = 30 mL/hr |
| 25 mL/hr = 25 gtt/min | 45 gtt/min = 45 mL/hr |
| 50 mL/hr = 50 gtt/min | 60 gtt/min = 60 mL/hr |
| 100 mL/hr = 100 gtt/min | 120 gtt/min = 120 mL/hr |
| With 60 gtt/mL tubing, gtt/min = mL/hr numerically. Formula: (mL/hr x 60) / 60 = mL/hr |
mL/hr to gtt/min Conversion Table (Macrodrip, DF = 10 gtt/mL)
| mL/hr to gtt/min | gtt/min to mL/hr |
|---|
| 30 mL/hr = 5.00 gtt/min | 5 gtt/min = 30 mL/hr |
| 60 mL/hr = 10.00 gtt/min | 10 gtt/min = 60 mL/hr |
| 75 mL/hr = 12.50 gtt/min | 12 gtt/min = 72 mL/hr |
| 100 mL/hr = 16.67 gtt/min | 15 gtt/min = 90 mL/hr |
| 120 mL/hr = 20.00 gtt/min | 20 gtt/min = 120 mL/hr |
| 150 mL/hr = 25.00 gtt/min | 25 gtt/min = 150 mL/hr |
| 200 mL/hr = 33.33 gtt/min | 30 gtt/min = 180 mL/hr |
| 250 mL/hr = 41.67 gtt/min | 40 gtt/min = 240 mL/hr |
| 300 mL/hr = 50.00 gtt/min | 50 gtt/min = 300 mL/hr |
| 400 mL/hr = 66.67 gtt/min | 60 gtt/min = 360 mL/hr |
| 500 mL/hr = 83.33 gtt/min | 80 gtt/min = 480 mL/hr |
| Formula: gtt/min = (mL/hr x 10) / 60 = mL/hr / 6, and mL/hr = gtt/min x 6 |
mL/hr to gtt/min Conversion Table (Macrodrip, DF = 15 gtt/mL)
| mL/hr to gtt/min | gtt/min to mL/hr |
|---|
| 20 mL/hr = 5.00 gtt/min | 5 gtt/min = 20 mL/hr |
| 40 mL/hr = 10.00 gtt/min | 10 gtt/min = 40 mL/hr |
| 60 mL/hr = 15.00 gtt/min | 15 gtt/min = 60 mL/hr |
| 80 mL/hr = 20.00 gtt/min | 20 gtt/min = 80 mL/hr |
| 100 mL/hr = 25.00 gtt/min | 25 gtt/min = 100 mL/hr |
| 120 mL/hr = 30.00 gtt/min | 30 gtt/min = 120 mL/hr |
| 150 mL/hr = 37.50 gtt/min | 40 gtt/min = 160 mL/hr |
| 200 mL/hr = 50.00 gtt/min | 50 gtt/min = 200 mL/hr |
| 250 mL/hr = 62.50 gtt/min | 60 gtt/min = 240 mL/hr |
| 300 mL/hr = 75.00 gtt/min | 75 gtt/min = 300 mL/hr |
| 400 mL/hr = 100.00 gtt/min | 100 gtt/min = 400 mL/hr |
| 500 mL/hr = 125.00 gtt/min | 120 gtt/min = 480 mL/hr |
| Formula: gtt/min = (mL/hr x 15) / 60 = mL/hr / 4, and mL/hr = gtt/min x 4 |
mL/hr to gtt/min Formula
Gtt/Min = (mL/Hr * D) / 60
D is the drop factor in gtt/mL, printed on the IV tubing package. Dividing by 60 converts the hourly rate to a per-minute rate. The inverse to find mL/hr: mL/hr = (gtt/min x 60) / D. Always round gtt/min to the nearest whole number since partial drops cannot be counted at the bedside.
IV Tubing Drop Factors
The drop factor is a property of the tubing set, not the fluid or medication. It is always printed on the tubing package and must be verified before calculating.
Standard IV Tubing Drop Factors and Clinical Use
| Tubing Type |
Drop Factor |
Mental Math Shortcut |
Typical Clinical Use |
| Macrodrip | 10 gtt/mL | gtt/min = mL/hr / 6 | Rapid fluid resuscitation, blood transfusion (trauma, surgery) |
| Macrodrip | 15 gtt/mL | gtt/min = mL/hr / 4 | Standard adult IV fluids, common in US hospital sets |
| Macrodrip | 20 gtt/mL | gtt/min = mL/hr / 3 | Standard adult IV fluids, common in international hospital sets |
| Microdrip | 60 gtt/mL | gtt/min = mL/hr (same number) | Pediatric, neonatal, ICU titrated drips, low-volume infusions |
| Drop factor is always printed on the IV tubing package label. Verify before calculating. |
Microdrip Shortcut (60 gtt/mL)
With microdrip tubing (60 gtt/mL), gtt/min equals mL/hr numerically. A 45 mL/hr order = 45 gtt/min. This holds because (mL/hr x 60) / 60 = mL/hr. No equivalent shortcut exists for macrodrip tubing; each drop factor requires its own calculation.
Bedside Drop Counting
Bedside Drop Counting Methods (Gravity Sets)
| Count Interval |
Multiply By |
Best For |
| 15 seconds | x 4 | Rates above 20 gtt/min |
| 30 seconds | x 2 | Most clinical rates (balance of speed and accuracy) |
| 60 seconds | x 1 | Rates below 10 gtt/min (most precise) |
Gravity drip set calculations are required when electronic infusion pumps are unavailable, in home health settings, or for certain infusions where pump precision is not indicated. Even when pumps are in use, nurses verify the programmed rate against a manual gtt/min calculation as a standard safety check.