Pharmacokinetic Elimination Half-Life (t½), Clearance & Volume of Distribution Calculator

Compute first-order drug elimination t₁/₂ = (0.693 × V_d) / CL.

Elimination Half-Life (t₁/₂)
6.07 hours
Elimination Rate Constant (k_e) 0.11 hr⁻¹
97% Washout Time (5 × t₁/₂) 30.33 hours
Initial IV Bolus Peak (C₀ = Dose/V_d) 11.9 mg/L
Inputs
L
Apparent Volume of Distribution (V_d) in liters.
L/hr
Total systemic drug clearance (CL) in liters per hour.
mg
Initial IV bolus dose administered in milligrams.
Results & Graph
Elimination Half-Life (t₁/₂)
6.07 hours
Elimination Rate Constant (k_e)
0.11 hr⁻¹
97% Washout Time (5 × t₁/₂)
30.33 hours
Initial IV Bolus Peak (C₀ = Dose/V_d)
11.9 mg/L

Elimination Half-Life (t₁/₂)

Graph 1 • Volume Of Distribution L Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 hours 4.9 hours 9.8 hours 50%: 3.03 hours 3.0 50% 75%: 4.55 hours 4.5 75% 100%: 6.07 hours 6.1 100% 125%: 7.58 hours 7.6 125% 150%: 9.1 hours 9.1 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Elimination Half-Life (t₁/₂) 6.07 hours Elimination Rate Constant (k_e) 0.11 hr⁻¹ 97% Washout Time (5 × t₁/₂) 30.33 hours Initial IV Bolus Peak (C₀ = Dose/V_d) 11.9 mg/L
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Elimination Half-Life (t₁/₂)6.07 hoursElimination Rate Constant (k_e)0.11 hr⁻¹97% Washout Time (5 × t₁/₂)30.33 hoursInitial IV Bolus Peak (C₀ = Dose/V_d)11.9 mg/L
Summary: With V_d = 42 L and CL = 4.8 L/hr, elimination rate constant k_e = 0.114 hr⁻¹ and biological half-life is 6.07 hours (~30.3 hrs for 97% washout).
Summary: With V_d = 42 L and CL = 4.8 L/hr, elimination rate constant k_e = 0.114 hr⁻¹ and biological half-life is 6.07 hours (~30.3 hrs for 97% washout).
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Formula & Mathematical Methodology: PK Half-Life & Clearance Reference Equation

ke = CL / Vd
t1/2 = ln(2) / ke = (0.69315 × Vd) / CL
97% Washout = 5 × t1/2
k_e = CL / V_d; t_1/2 = ln(2) / k_e = (0.69315 × V_d) / CL; 97% Washout = 5 × t_1/2
  • volumeOfDistributionL: Volume Of Distribution L (L)
  • systemicClearanceLhr: Systemic Clearance Lhr (L/hr)
  • ivBolusDoseMg: Iv Bolus Dose Mg (mg)

Rounding: Laboratory and clinical equations retain full floating-point precision and round displayed results to 2 decimal places.

Worked Example: Reference Calculation: PK Half-Life & Clearance

Compute first-order drug elimination t₁/₂ = (0.693 × V_d) / CL.

  1. Enter the reagent concentrations, assay readings, or clinical laboratory parameters.
  2. Compute the standard formula: k_e = CL / V_d; t_1/2 = ln(2) / k_e = (0.69315 × V_d) / CL; 97% Washout = 5 × t_1/2.
  3. Review the primary result, supporting reference intervals, and 3 SVG visualizations.
Result: Evaluates PK Half-Life & Clearance via k_e = CL / V_d; t_1/2 = ln(2) / k_e = (0.69315 × V_d) / CL; 97% Washout = 5 × t_1/2.

Frequently Asked Questions

What formula is used by the Pharmacokinetic Elimination Half-Life (t½), Clearance & Volume of Distribution Calculator?

It computes k_e = CL / V_d; t_1/2 = ln(2) / k_e = (0.69315 × V_d) / CL; 97% Washout = 5 × t_1/2 and plots three custom SVG graphs showing parameter sensitivity and component breakdowns.

Can I compare different reagent dilutions or lab scenarios side by side?

Yes. Use the "Compare (0/3)" button to pin up to 3 scenarios side by side.

Are entered values stored on any server?

No. Every calculation runs 100% locally in your browser.

Health & Fitness · Pharmacology & Critical Care

Pharmacokinetic Elimination Half-Life (t½), Clearance & Volume of Distribution Calculator: inputs, method, and how to read the result

Compute first-order drug elimination t₁/₂ = (0.693 × V_d) / CL.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Volume Of Distribution L: Apparent Volume of Distribution (V_d) in liters.
  • Systemic Clearance Lhr: Total systemic drug clearance (CL) in liters per hour.
  • Iv Bolus Dose Mg: Initial IV bolus dose administered in milligrams.

What the calculation includes

With the default values shown, Elimination Half-Life (t₁/₂) is 6.07 hours. The calculation follows PK Half-Life & Clearance Reference Equation; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Volume Of Distribution L from 42 L to 46 L changes Elimination Half-Life (t₁/₂) from 6.07 hours to 6.64 hours. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard IUPAC atomic weights, 25°C (298.15 K) reference thermodynamics, and published clinical literature equations.
  • Educational and laboratory reference tool only; clinical scoring calculators do not replace professional medical judgment or institutional protocols.

Scope: IUPAC / NIH Laboratory & Clinical Reference Standard Check the assumptions and limitations against your situation before relying on the estimate.

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