Bioreactor / Perfusion Calculator: VVD, dilution rate, residence time & CSPR

Continuous- and perfusion-culture math, instantly

Perfusion and chemostat runs come with a handful of relations you compute over and over — how fast you’re turning over the vessel (VVD), the dilution rate, how long media sits in the tank, and how much fresh media each cell sees per day (CSPR). This does all of them from three inputs, live, in the browser.

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What it computes

For a working volume V and media flow F:

Perfusion rate (VVD) = F / V — vessel volumes per day.
Dilution rate D = VVD / 24 (1/h). At chemostat steady state, D equals the specific growth rate µ.
Residence time τ = 1 / D = 24 / VVD (h) — how long, on average, media stays in the vessel.
Cell-specific perfusion rate (CSPR) = F / (VCD · V), reported in pL/cell/day — fresh media delivered per viable cell per day. Typical perfusion targets sit around 30–100 pL/cell/day.
Media consumption in mL/day and L/day.
td if D = µ — the doubling time a chemostat would impose at this dilution rate, ln2 / D, as a cross-check against your doubling-time measurement.

Flow can be entered as VVD, mL/day, mL/min, or L/day — all normalized to mL/day under the hood.

Worked check

V = 1 L, F = 1 VVD, VCD = 20 ×10⁶ cells/mL → flow 1000 mL/day, VVD 1.0, D 0.042 /h, τ 24 h, CSPR 50 pL/cell/day, media 1 L/day.

Embed it on your site

<link rel="stylesheet" href="https://www.37degrees.io/interactive-tools/bioreactor-perfusion/styles.css" />

<div id="bioreactor-widget-embed"></div>

<script>
  // Optional: window.BIOREACTOR_THEME = "light";
</script>
<script src="https://www.37degrees.io/interactive-tools/bioreactor-perfusion/widget.js"></script>

Credits

Built and maintained by 37degrees. Standard continuous-culture relations — no third-party libraries, no data leaves the browser.