Lab Tools

IC₅₀ calculator.

Enter inhibition assay data, fit a four-parameter logistic curve, and estimate the half-maximal inhibitory concentration.

How to use the calculator

1.Paste or type data: Paste concentration & response values directly from Excel or type them column-wise (Concentration, Response 1, Response 2...).
2.Process data: Click “Process data” to summarize replicates and calculate SEM error bars.
3.Calculate IC₅₀: Check your processed input table and press “Calculate IC₅₀”.
4.Review & Graph: Note your calculated values and refer to the fitted dose–response curve graph.

4PL Model & Method

Y = Bottom + (Top − Bottom) / (1 + (X / IC₅₀)ⁿ)

Nonlinear least squares fitting of the four-parameter logistic (Hill equation) model using Nelder-Mead optimization. Calculates R² goodness of fit, SEM for replicates, and direct 50% response interpolation.

IC₅₀: Concentration producing 50% of maximal inhibition
Hill coefficient (n): Steepness factor of the dose–response curve

Data entry

Paste or type concentration and response values (% growth inhibition). Use tabs, commas, or spaces between columns. Multiple response columns are averaged with SEM error bars.

How to Cite

CellsInVitro IC50 Calculator. CellsInVitro Lifesciences Pvt. Ltd. Version 1.0. Available at: https://cellsinvitro.com/tools/ic50

Version & Release Info

v1.0

Calculations support laboratory assay planning, documentation, and SOP verification against manufacturer specifications.

Release Date: March 22, 2026Publisher: CellsInVitro Lifesciences