The original app · Web · iOS
Expert Buffer Designer Classic
The first app we released: design a single- or dual-species buffer from first principles, and see how robust it is before you ever weigh a reagent. It's still free, on the web and on iOS.
Its successor is here. The new Expert Buffer Designer, part of the Expert Bioprocess Designer Suite, is in beta. It brings the pH your meter will read, full temperature correction, four ionic-strength models, recipes in the reagent forms on your shelf, what-if sweeps, and a library shared with the suite's other apps. Join the beta →
In the classic app, the natural-language (GenAI) buffer entry is currently unavailable. Every other designer and calculator works as before.
See it in action
From a request to a recipe
Set up 0.1 M phosphate with 0.1 M sodium chloride at pH 7.4, and the engine returns the exact recipe — sodium phosphate monobasic and dibasic balanced to land on pH 7.400, with sodium chloride for ionic strength.
Every result is fully characterized: compounds, ions and ionic species, plus the sensitivity heat-map that shows how robust the buffer is across the working range.
No buffer too complex
The most complex buffer, made simple
Mix two buffer species, a base and a salt — and let the engine solve the whole system at once, or auto-adjust to a target pH.
Sodium phosphate monobasic and citric acid (two buffering species), with sodium hydroxide and sodium chloride — four components solved together to a predicted pH of 5.74.
Designed for robustness
Stress-test a buffer before you scale
The sensitivity heat-map perturbs each compound across ±10% and predicts the pH at every point — so you can see how forgiving a formulation is, and choose a robust one on purpose.
Each cell is the predicted pH when the two phosphate compounds are off by the row and column amounts. Green means the pH barely moves; amber and red flag fragile formulations. Here the buffer holds within 0.1 pH units even at ±10%.
What it does
Buffer design, backed by the chemistry
Ionic-strength-aware pH
Goes beyond Henderson–Hasselbalch: models how ionic strength shifts each species' pKa, so the predicted pH matches what you actually measure.
Single and dual buffer species
A library of Good's, biochemical and standard buffers — alone or as dual-species systems — with full composition and ion detail.
±10% sensitivity heat-map
A color-coded map shows how much the pH drifts under ±10% concentration error across the range — find the robust working zone before you scale up.
Super Calculator
Combine up to three buffer compounds and a salt, then calculate the pH of the mix — or let the app add acid or base to reach a target pH.
Your saved buffers
Save, name and reuse your buffers. They're kept on the device you work on, and signing in is optional.
Web and iOS
Runs in the browser and on iOS — at the bench, at your desk, or on the go.
From the literature
The method, published
Buffer Design for Biopharmaceutical Processes
An online tool for designing and understanding buffers — buffer chemistry, a three-step design workflow, and robustness analysis. Featured report, July–August 2024.
Read the article →Decades of downstream experience
Built by Natraj Ram, Ph.D., a biopharmaceutical process-development expert named on several antibody-purification patents and active in industry buffer-management collaborations.
About us →