Local Anesthetic Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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A dose number is useful only when its assumptions are clear. Local Anesthetic Calculator turns the selected medication details into the specific reference calculation implemented here, while keeping clinical prescribing separate from arithmetic.

What this calculator does

Local Anesthetic Calculator uses Drug, Weight, and Concentration to produce the maximum allowable subcutaneous dose used by this calculator. It only uses the fields shown in this calculator; it does not silently add tests, diagnoses, symptoms, or clinical variables that are absent from the interface. local-anesthetic flow: drug, weight, concentration; applies drug-specific maximum-dose references.

How to use it

Enter or select Drug, Weight, and Concentration. Double-check the medication, route or formulation choices, weight/unit conversions, and concentration before relying on the output. If an input is unknown, it is better to leave the calculation unresolved than to invent a value.

How the calculation works

The calculator looks up a drug-specific mg/kg factor and single-dose cap, multiplies the factor by weight, and uses the lower of the weight-based amount and the cap. It converts the selected percent solution to mg/mL and divides the permitted milligrams by that concentration to estimate volume. The current table is for bupivacaine, lidocaine, mepivacaine, and ropivacaine without epinephrine.

Example

For example, choose lidocaine, enter 70 kg, and select a 1% solution. Weight-based dose is 70 × 4.5 = 315 mg, but the calculator applies its 300 mg single-dose cap. A 1% solution is 10 mg/mL, so the displayed maximum volume would be 30 mL. This illustrates the table; it is not an administration recommendation.

How to interpret the result

Read maximum allowable subcutaneous dose as the output of the selected reference rule, not as proof that the medicine, formulation, route, schedule, or dose is appropriate for a particular person. The useful next step is to compare the arithmetic with the current order or label and patient-specific clinical factors.

Limitations and notes

Maximum-dose tables are approximations, not a guarantee of safety. Site, vascular absorption, epinephrine, age, pregnancy, liver/cardiac disease, cumulative dosing, and institutional policy can change the safe limit. The calculator’s table is explicitly the without-epinephrine branch.