Bench Calculators
These are the numbers you need before you touch anything: how much to weigh, how far to dilute, how fast to spin, how much to plate.
The three most used are molarity, dilution and percent concentration. They are three phrasings of the same equation, kept separate because the real difficulty at the bench is not the arithmetic but the units: mg/mL and M differ by a molecular weight, % (w/v) and % (v/v) are not the same quantity, and ppm approximates mg/L only in dilute aqueous solution.
Read the two centrifugation tools together: RCF / RPM answers “how fast is this machine spinning”, while rotor k-factor answers “does this protocol still hold in a different rotor” — at identical g-force, two rotors can differ threefold in the time needed, which is routinely missed.
The cell tools divide cleanly: hemocytometer counts, OD₆₀₀ conversion measures, split ratio works backwards, and plate colony counting explains why the countable range is 30–300 — that is not a convention, it follows from 1/sqrt(n) counting precision.
The recurring trap here is entering a total where a per-unit value is asked for. Every tool that supports batches multiplies by the count again, so the answer is wrong by exactly that factor — and it looks perfectly reasonable.
Bench calculators
Centrifuge RCF (g) ↔ RPM Converter — Relative Centrifugal Force Calculator
Convert between relative centrifugal force (× g) and rotor speed (rpm) in both directions using rotor radius, with common reference values.
Molarity, Mass, and Volume Calculator — Solve for Concentration, Volume, or Mass
Solve for concentration, volume, or mass given the other two — supports mM/µM/nM and mg/µg/ng.
Solution Dilution Calculator (C1V1 = C2V2)
Calculate stock, fold, and serial dilutions in one step — outputs the exact solvent volume to add.
Nucleic Acid Concentration Calculator: OD260, ng/µL, and pmol Conversion
Convert A260 absorbance to mass concentration and interconvert ng and pmol for dsDNA, ssDNA, RNA, and oligonucleotides.
Hemocytometer Cell Concentration Calculator
Enter counts from each large square and the dilution factor to calculate cell concentration, total cell number, and volume needed for plating.
Buffer Preparation Calculator (Henderson-Hasselbalch)
Calculate the acid/base component ratio and the mass of each needed to hit your target pH.
PCR Reaction Setup Calculator (with Multi-Sample Master Mix)
Calculate the volume of each component and water make-up from stock and final concentrations; supports batch master mix preparation for multiple samples.
DNA / RNA Copy Number Calculator (Plasmid Standards, qPCR, ddPCR)
Calculate copies/µL, copies per reaction, and single-copy mass from concentration and length; generate a standard-curve dilution series.
Primer Resuspension and Dilution Calculator
How much water to add for lyophilized primer resuspension, how to dilute to working stock, and how many reactions your tube will support.
Transformation Efficiency Calculator
Calculate transformation efficiency in CFU/µg with automatic plating-ratio correction — omitting this step throws your result off by 10-fold or more.
Cell Culture Vessel Converter — Surface Area, Seeding Density & Drug Volume
Scale seeding cell counts and drug volumes between culture plates, dishes, and flasks: cell number follows area, drug volume follows medium — and these ratios differ.
Percent Concentration Converter (% w/v, % w/w, % v/v, ppm ↔ mol/L)
The 37% on the bottle and 12 mol/L in the protocol are the same concentrated HCl — convert between % (w/v), % (w/w), % (v/v), ppm, g/L, and mol/L in one step.
OD₆₀₀ to Cell Concentration Calculator (Dilution Correction / Plate Reader Path-Length / Inoculum Back-Calculation)
Convert OD₆₀₀ readings to cells/mL and total cell count, with dilution back-calculation, path-length correction, and linear-range checking.
Gel Band Size Estimation (DNA bp / Protein kDa, Semi-log Standard Curve)
Fit a semi-log curve to marker migration distances and estimate unknown band sizes; flags linear-interpolation overestimation and out-of-range extrapolation.
Cell Split Ratio & Regrowth Time Calculator — Back-Calculate the Right 1:N Ratio from Doubling Time
Calculate regrowth time after a 1:N cell split, or back-calculate the ratio needed. Diluting twice as much buys only one extra doubling, not twice the time.
Plate Colony Count and CFU/mL Calculator (Countable Range / ISO Weighted Average / Poisson Error)
Enter colony counts by dilution; the tool picks countable plates, applies ISO 4833 weighted average, and returns CFU/mL with Poisson error — limits from 1/√n.
Centrifuge k-Factor Calculator: Convert Run Time When Switching Rotors
Compute rotor k-factor from r_min, r_max, and rated speed; scale run time when switching rotors. RCF measures force — k accounts for path length too.
Gibson Assembly Fragment Amount Calculator (Multi-Fragment Molar Ratio and pmol Conversion)
Calculate ng per insert from vector length and amount; auto-selects 2–3 vs. 4–6 fragment protocols and checks total pmol against the recommended range.
Restriction Digest Setup Calculator (Units, Glycerol Limit, and Volume Breakdown)
Calculate enzyme units and volume needed, check final glycerol against the 5% star-activity limit, and get a complete DNA/buffer/enzyme/water breakdown.
Buffer Recipe Calculator: TAE / TBE / PBS and Custom Formulas — Mass and Volume Conversions
Select a recipe and volume; get exact mass or volume per component with all calculations shown, plus EDTA pH-8 dissolution and Tris temperature-drift warnings.
Agarose Gel Concentration Selector and Mass Calculator (with TBE/TAE Guidance)
Pick the right agarose percentage for your fragment size range, calculate grams for your gel tray, and choose between TBE and TAE based on downstream plans.
Osmolarity Calculator — mOsm Conversion & Isotonicity Check
Compute solution osmolarity (mOsm) from concentration × particle count, with optional osmotic coefficient φ, and compare against plasma 275–295 mOsm/kg.
Molecular Weight Calculator: Molar Mass and Weighing Mass from Chemical Formula
Enter a chemical formula to get molar mass—supports nested parentheses and hydrates (CuSO4·5H2O)—then calculates grams to weigh for a target concentration and volume. Atomic weights from CIAAW abridged standard values.
Complete Medium Calculator — Serum and Supplements Back-Calculated from Final Volume
Enter final volume, serum %, and additive stock folds; get exact basal medium and supplement volumes, plus the serum drift from the common full-bottle mistake.
Radioactive Isotope Decay Calculator (³²P / ³⁵S / ¹²⁵I / ³H Remaining Activity)
Calculate remaining activity since the reference date, extra volume needed for an equivalent dose, and days to reach 50%, 25%, or 10% of initial activity.
Ammonium Sulfate Precipitation Calculator: Solid Amount for Protein Fractionation
Enter initial and target saturation, solution volume, and temperature to calculate grams of solid ammonium sulfate needed and the resulting volume increment.
Animal Dosing Calculator — mg/kg to Injection Volume & Batch Prep
Enter dose (mg/kg), body weight, and stock concentration to calculate injection volume; includes batch preparation and maximum volume limits by route.
Beer-Lambert Law Calculator: Absorbance, Extinction Coefficient, and Concentration
Solve for absorbance, extinction coefficient, concentration, or path length using Beer-Lambert law — enzyme assays, NAD(H) kinetics, small-molecule QC.
Buffer pH Temperature Correction Calculator (Tris / HEPES / MOPS)
Enter preparation and working temperatures to get pH drift and room-temperature set point; Tris shifts 0.28 pH per 10°C — over ten times phosphate buffer.
Circular Dichroism Mean Residue Ellipticity Calculator (CD [θ]MRE and Δε)
Enter raw ellipticity (mdeg), protein concentration, and path length to get [θ]MRE and Δε, with path-length unit reminders to prevent order-of-magnitude errors.
ChIP-qPCR Percent Input Calculator (% Input Enrichment Analysis)
Calculate ChIP % Input enrichment per locus; enter input fraction and Ct values, with IgG normalization — prevents the classic dilution-factor error.
Dialysis Buffer Exchange Calculator — Desalting, Imidazole Removal, Buffer Swap
Calculate how many dialysis rounds you need and the residual concentration after each step; quantify exactly how much sequential buffer changes outperform a single large-volume exchange.
Bacterial / Cell Doubling Time and Growth Rate Calculator
Enter two log-phase OD or cell count measurements to calculate doubling time, specific growth rate μ, number of generations, and predicted cell density.
Drug Dilution Calculator for Cell Assays — DMSO Stock, Working Solution & Well DMSO%
Calculate DMSO stock volume from compound mass and MW; verify per-well DMSO%; flag cases where a pipettable intermediate dilution is required.
Dual-Luciferase Reporter Normalization Calculator (Firefly / Renilla Relative Luciferase Activity)
Paste Firefly and Renilla RLU values to get per-well normalized activity, group means ± SD, and fold induction with the control auto-set to 1.
Degree of Labeling (DOL) Calculator: Fluorescent Labeling Stoichiometry for Antibodies and Proteins
Calculate DOL (F/P ratio) and protein concentration from A₂₈₀ and dye absorbance; built-in constants for FITC, Alexa Fluor 488/555/647, Cy3/Cy5 with 280 nm dye correction.
FRET Efficiency and Donor–Acceptor Distance Calculator (Förster Equation)
FRET three-way calculator: efficiency E from distance R and Förster radius R₀, distance R from efficiency E, or efficiency from donor fluorescence quenching; covers 2–14 nm.
HPLC Column Efficiency Calculator: Theoretical Plate Count N, Resolution Rs, and Capacity Factor k′
Enter retention times and peak widths to calculate N, H, k′, and Rs — confirm column efficiency and whether two peaks are baseline-resolved.
CO₂–pH Calculator for Cell Culture Media
Three-way conversion among CO₂%, NaHCO₃ concentration, and medium pH; RPMI/DMEM/MEM presets, altitude correction, and the formula behind yellowing medium.
Buffer Ionic Strength Calculator (IEX · SEC · EMSA Condition Check)
Calculates solution ionic strength I (mol/L) from ion concentrations and charges; includes PBS presets for quick buffer verification before IEX and SEC runs.
Ki Calculator (Cheng-Prusoff Equation) — IC50 to Ki Conversion
Convert IC50 to Ki using the Cheng-Prusoff equation for competitive, uncompetitive, or pure noncompetitive enzyme inhibition.
DNA Ligation Calculator — Vector and Insert Amount (T4 Ligase)
Enter linearized vector amount and size, insert size, and molar ratio to calculate required insert mass and fmol values for T4 ligase cloning.
Limiting Reagent and Theoretical Yield Calculator (Synthesis / Biochemical Reactions)
Enter each reactant's molecular weight, mass, and stoichiometric coefficient to instantly identify the limiting reagent, theoretical yield, and percent yield.
Liquid-Liquid Extraction Efficiency Calculator (Multiple Extractions and Partition Coefficient)
Calculate cumulative extraction recovery from partition coefficient and volumes; supports pH correction for weak acids/bases and contrasts multiple vs. single large-volume extraction strategies.
Mass Accuracy Calculator: ppm Error and Mass Window for High-Resolution MS
Enter measured and theoretical m/z to get ppm error and mDa deviation, or back-calculate XIC mass extraction windows from theoretical mass and ppm tolerance.
Multiplicity of Infection (MOI) Calculator
Enter cell count, target MOI, and viral titer to get the required virus volume; Poisson-based infection rate and single-infection fraction; back-calculate actual MOI from measured infection rate.
ESI-MS Adduct m/z Calculator ([M+H]+, [M+Na]+, Neutral Mass)
Compute m/z for common ESI adducts ([M+H]+, [M+Na]+, [M+2H]²+) from neutral exact mass or molecular formula; back-calculate neutral mass from observed m/z.
NGS Library Molarity & Equimolar Pooling Calculator (Qubit ng/µL to nM)
Convert Qubit mass concentration and Bioanalyzer fragment length to library molarity (nM), then get dilution volumes and an equimolar pooling plan.
PCR Run Time Calculator — Amplicon Size × Extension Rate
Calculate PCR run time from amplicon size and polymerase extension rate; instantly see per-cycle extension time and how much time a faster polymerase saves.
Peptide Fragment Ion m/z Calculator (b/y Ions, MS/MS Spectrum Annotation)
Enter a single-letter peptide sequence to get monoisotopic m/z values for all b/y ions; supports carbamidomethyl Cys and oxidized Met for LC-MS/MS spectrum annotation.
Protein Net Charge Calculator (pH-Dependent)
Enter an amino acid sequence and pH to estimate the net charge via the Henderson-Hasselbalch equation; useful for IEX resin selection and pI range analysis.
Protein Purification Table: Specific Activity, Yield, and Purification Fold Calculator
Enter volume, protein concentration, and activity for each purification step; calculates specific activity, yield, and purification fold and generates a publication-ready table.
SDS-PAGE Gel Preparation Calculator (Resolving Gel & Stacking Gel)
Enter acrylamide percentage and per-gel volume; calculate acrylamide, Tris, SDS, APS, TEMED, and water for both gel layers, with multi-gel batch scaling.
TCID₅₀ Calculator — Virus Infectious Titer via Reed-Muench Method
Compute TCID₅₀/mL from serial-dilution well data using the Reed-Muench cumulative method; shows the intermediate table to catch direction-reversal mistakes.
Transfection Volume Calculator — Lipofectamine 3000 / PEI Scaled by Growth Area
Scale Lipofectamine 3000 or PEI transfection volumes by growth area; gives a master mix with 10% overage that reproduces manufacturer protocol table values.
Subcutaneous Tumor Volume Calculator (Caliper Measurement / TGI Tumor Growth Inhibition)
Compute subcutaneous tumor volume (mm³) from caliper long and short axes using the modified ellipsoid or ellipsoid formula, with optional TGI calculation.
Scratch Wound Healing Assay Calculator: Wound Closure Percentage and Migration Rate
Enter initial and endpoint scratch widths to calculate per-replicate wound closure %, mean ± SD, and leading-edge migration rate for wound healing assay data.
Z' Factor Calculator: HTS Assay Quality Assessment for High-Throughput Screening
Paste positive and negative control readings to instantly compute Z' factor, S/B, S/N, and CV — assess whether your HTS assay meets quality standards.
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