All-in-One Lab Solution Calculator for Wet Labs: Dilutions, Plates, DMSO Caps, Buffers — in One App
🧪 Open the Lab Solution Calculator
Pro tool — access is checked inside the app. Login is handled by Supabase.
(If you are logged in on Streamlit but not here, the app will still let you in.)
Why we built it
Preparing solutions looks simple, until you need to do it fast, reproducibly, and for many conditions. You jump between C1V1 scribbles, old Excel templates, plate layouts, and DMSO limits for your cell assay. One bad dilution or a final vehicle of 0.2% instead of 0.1% can waste an entire plate.
So we turned our everyday lab math into a single, login-based web app: the Lab Solution Calculator. It runs in Streamlit (so it is clean and fast), uses Supabase for authentication, and groups all the calculations that biologists actually use not just C1V1.
What it actually is
The calculator is a web-based lab math assistant for:
- biologists and cell-culture labs
- assay/development teams running dose–response or screening
- teaching labs who want a single, reusable calculator
- core facilities who want to give “Pro” to selected users
Unlike generic dilution calculators, this one:
- runs in Streamlit (Python-powered, easy to extend)
- uses Supabase for login, signup, and storing user presets
- can lock advanced modules based on subscription (
plan = "pro") - exports plans to CSV or PDF (via
fpdf) - remembers user reagents in a Supabase table
17 calculator modes inside
The current script you are running already has 17 lab calculators inside one interface. That’s what makes it more powerful than a single-purpose online tool.
Core calculation modes
- Single dilution (C1V1 = C2V2) — with vehicle % and intermediate-stock suggestion.
- Serial dilutions — define start conc, factor, steps, final volume → export CSV/PDF.
- Experiment series (plate-like) — enter final concentrations → get per-well plan + overfill.
- From solid (mg → solution) — turn powder mass + MW into exact volume, with light-sensitivity warnings.
- Unit converter (mg/mL ↔ mM) — tiny but used daily.
- % solutions (w/v, v/v) — e.g. 2% w/v, 10% v/v, media & fixatives.
- Molarity from mass & volume — “I dissolved 12 mg in 10 mL — what’s the M?”
- OD / culture dilution — C1V1 logic adapted for bacterial/yeast cultures.
- Master mix / qPCR mix — define per-reaction components → app multiplies + overfill.
- Make X× stock from current stock — turn 1× into 5× or 10×.
- Acid / base dilution (HCl, H₂SO₄, NH₃) — auto-calculates volume from density + purity.
- Buffer helper (PBS / TBS / Tris) — gives gram amounts for 1 L, ready to copy into protocol.
- Beer–Lambert / A280 — absorbance → concentration.
- Cell seeding calculator — cells/mL → how much to pipette per well.
- Plate DMSO cap checker — checks wells against your DMSO/EtOH limit.
- Aliquot splitter — divide total volume into aliquots, keep dead volume.
- Storage / stability helper — quick guidance for PBS, Tris, retinal, ampicillin, etc.
Why the DMSO cap checker matters
Most cell assays have a vehicle limit — often 0.1–0.5% DMSO. Your app actually calculates the vehicle coming from the stock (because you specify the stock solvent and %), divides it by the final well volume, and flags wells that exceed the cap.
That’s something typical “online dilution calculators” do not do. It’s one of the strongest SEO angles for this page: “check if my 96-well plate exceeds DMSO limit”, “DMSO cap calculator for cell-based assays”, “how much DMSO is ok in final volume”.
Smart presets = less typing
In the sidebar, the app lets you pick common scenarios:
- Cell culture (0.1% DMSO, 300 µL)
- Chemistry (no vehicle, 1000 µL)
- qPCR / assay (20 µL)
When you pick one, it pre-fills final volume, max vehicle, and stock vehicle type. That makes it much harder to make mistakes when you’re doing 20 plates a day.
Free vs Pro (Supabase-powered)
Your Streamlit code does this:
plan = get_subscription_plan(user.id) and then:
if plan != "pro": → show “this tool is for Pro users”.
That single check gives you a mini SaaS model:
- let anyone sign up
- keep basic modes (C1V1, % solution) free
- lock plate-like, DMSO checker, PDF export for Pro
- upgrade users manually in
public.subscriptions→ later Stripe
Why not just use Excel?
Excel is great, but it doesn’t:
- warn when vehicle % is too high
- store favorite reagents in a DB
- have auth and roles
- export protocol-style PDF from inside the calculator
That’s why we moved it to Streamlit.
Deploy it for your lab or course
Run it on Streamlit Cloud, check subscriptions in Supabase, give Pro access to your team.
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