Veterinary Math Reference (Conversions, Drug Concentrations, Drip Sets)
Common conversions and round-numbers veterinary teams actually look up - drug strengths, drip set factors, catheter sizes, unit conversions.
Category
Drug concentration
| Concentration | mg/mL | Notes |
|---|---|---|
| 1% | 10 mg/mL | Used for lidocaine, dexmedetomidine, propofol |
| 2% | 20 mg/mL | Lidocaine 2%, alfaxalone 1% = 10 mg/mL |
| 10% | 100 mg/mL | Calcium gluconate 10%, ketamine 100 mg/mL |
| 1:1000 (epinephrine) | 1 mg/mL | Standard adrenaline / epi concentration |
| 1:10000 | 0.1 mg/mL | Diluted epi for CPR / paediatric |
IV drip set drops per mL
| Set | Drops / mL |
|---|---|
| Macrodrip | 10, 15, or 20 (check the packaging) |
| Microdrip / paediatric | 60 |
| Drops/min from mL/hr | mL/hr × drop factor ÷ 60 |
Quick body weight defaults (for IV catheter & ET tube sizing)
| Patient size | IV catheter (g) | ET tube (mm) |
|---|---|---|
| < 5 kg (toy / cat) | 22 g | 3.5–5.0 |
| 5–15 kg | 20 g | 5.0–7.5 |
| 15–30 kg | 18 g | 7.5–9.0 |
| 30 kg+ | 16 g | 9.0–12.0 |
A pocket reference of the conversions and round numbers you actually look up - drug strengths, drip factors, and catheter sizes by patient size, alongside the live converter above for weight, volume, temperature, and pressure.
Frequently asked questions
How do I convert a percentage drug concentration to mg/mL?
A 1% solution = 10 mg/mL. A 2% solution = 20 mg/mL. A 10% solution = 100 mg/mL. Multiply the % by 10. So lidocaine 2% is 20 mg/mL; calcium gluconate 10% is 100 mg/mL.
What's the drop factor for a microdrip set?
60 drops/mL. Macrodrip sets are 10, 15 or 20 drops/mL depending on manufacturer - always check the packaging. Microdrip is preferred for paediatric and small-animal patients because of precise flow control.
How do I calculate drops/min from mL/hr?
Drops/min = (mL/hr × drop factor) ÷ 60. Example: 30 mL/hr through a 15 drops/mL set = (30 × 15) ÷ 60 = 7.5 drops/min.