Molarity, dilutions, master mixes, centrifuge speeds, cell seeding, DNA and RNA concentration, plate layouts and curve fitting. Free to use, no sign-up, works on your phone at the bench.
Work out how much to weigh, what concentration you made, or what volume you need.
Example loaded: NaCl (58.44 g/mol) at 150 mM in 500 mL.
How much stock to add, and how much diluent to make it up with.
If the stock volume would be below your smallest pipetting volume, an intermediate dilution is added, made up to the intermediate volume. Example loaded: 1 M Tris stock to 50 mM in 100 mL. Use X for buffers like 10X PBS.
From your stock to the top of the series, with an intermediate dilution when one is needed, then every transfer and tube concentration.
If going straight from stock to tube 1 would mean pipetting less than your smallest volume, an intermediate dilution is added, made up to the intermediate volume. Example loaded: 10 mM stock to a 10 µM top concentration, then eight 1:3 steps of 100 µL.
Enter one value to see it in every common unit. Add a molecular weight to convert between molar and mass units.
Example loaded: BSA at 5 mg/mL (about 66,430 g/mol). For proteins and DNA, molecular weight is often given in Da, which is the same number in g/mol.
Scale one reaction up to a master mix, with extra to cover pipetting loss.
Enter each component as µL per reaction, or as its stock and final concentration. Water is worked out to make up the reaction volume, and template goes into each tube separately. Count no-template and other controls as reactions. Add water first and enzyme last, and keep the mix on ice. Example loaded: 25 µL PCR, 12 reactions, 10% extra.
Convert between rpm and relative centrifugal force (× g) for your rotor.
Use the maximum radius from your rotor's spec sheet, measured from the centre to the bottom of the tube. Example loaded: a typical microcentrifuge rotor.
How much cell suspension and medium to mix for an even seeding density.
Many cell counters report total cells and viability. Choose Total cells and the live count is worked out for you. Growth areas are typical values; check your vessel's datasheet, as they vary by manufacturer. Example loaded: 10,000 live cells per well across a 96-well plate.
Concentration and purity ratios from absorbance readings.
Assumes a 1 cm path length, which is what most spectrophotometers report. Enter readings as measured; the dilution is applied for you. Example loaded: dsDNA diluted 1:10.
Lay out standards, samples, controls and blanks, then copy the map into your spreadsheet or notebook.
Fills in this order: standards, blanks, controls, then samples. Replicates sit next to each other. Controls get the same number of replicates.
Click or drag across wells to paint them. Click a row letter or column number to paint the whole line. Leave the label empty to number wells automatically, or type one (for example S5) to mark replicates.
Pastes as a grid into Excel, Google Sheets or a Notion table. Your layout is kept in this browser.
Fit a standard curve or any x–y data, check how good the fit is, and work out concentrations for unknown samples.
Paste straight from a spreadsheet. Standards: one row per concentration (x), followed by one or more responses (y) as replicates. Samples: a name, followed by one or more responses. Header rows are ignored. Add a series for each curve you want to compare, up to six.
4PL suits most ELISA and immunoassay curves, and 5PL suits curves that aren't symmetrical. 1/Y² weighting stops the high standards dominating the fit, which often helps when responses span a wide range. The sample dilution is multiplied into every sample's result.