--- title: "Serial Dilution Calculator – Table & Volumes | MolDraw" url: https://www.moldraw.com/tools/free-chem-tools/serial-dilution-calculator.html description: "Free serial dilution calculator: concentration, transfer and diluent volume for every tube. E.g. 1 mM, 1:10 × 5 steps = 10 nM; 100 µL into 900 µL." lang: en publisher: Scidart Academy generated: 2026-10-31 --- [MolDraw](https://www.moldraw.com/) › [Chemistry tools](https://www.moldraw.com/tools/) › Serial Dilution Calculator # Serial Dilution Calculator **In short:** Plan an n-step serial dilution: the concentration in every tube and how much to transfer and how much diluent to add, as a printable table. The reverse calculator finds the factor or number of steps to reach a target. It is free, works in your web browser and needs no download. For a single dilution from a stock, the [C1V1 = C2V2 dilution calculator](https://www.moldraw.com/tools/free-chem-tools/dilution-calculator.html) is quicker. This page is for a series of tubes: dose–response curves, standard curves, MIC plates and cell or colony counts. **Quick answer:** Cn = C0 / Fn. A 1 mM stock diluted **1:10 five times** gives 100 µM, 10 µM, 1 µM, 100 nM and **10 nM**. For 1 mL per tube, move **100 µL into 900 µL** of diluent each time. Starting (stock) concentration Dilution factor per step Number of steps (tubes) Final volume per tube Equal volume left in every tube (correct for the volume moved on) Show concentrations in Molar mass (g/mol, for M ↔ mg/mL) Keep one unit (no automatic mM → µM → nM) ### Reverse: what factor or how many steps? Start Target Find Steps ## Serial dilution formulas `C_n = C_0 / F^n total dilution after n steps = F^n transfer = V / F diluent = V − V / F` `factor for n steps: F = (C_0 / C_target)^(1/n) steps for factor F: n = log(C_0 / C_target) / log F (round up)` `equal volume left in every tube: diluent = V, transfer = V / (F − 1), discard V / (F − 1) from the last tube` F is the dilution factor of one step: 1 part sample in F parts total. 1:10 means F = 10 (1 part + 9 parts diluent), and a two-fold series has F = 2. A half-log series uses F = √10 ≈ 3.162, so every second tube is ten times weaker. | Series | Factor | Transfer + diluent for 1 mL | Typical use | | --- | --- | --- | --- | | Ten-fold | 10 | 100 µL + 900 µL | Bacterial and cell counts, wide concentration ranges | | Two-fold | 2 | 500 µL + 500 µL | MIC tests, antibody titres, ELISA standards | | Half-log | 3.162 | 316.2 µL + 683.8 µL | Dose–response (IC₅₀/EC₅₀) curves | | Five-fold | 5 | 200 µL + 800 µL | Standard curves | ## How to do a serial dilution 1. Enter the stock concentration, the factor per step, the number of tubes and the final volume per tube. 2. Label the tubes and add the diluent volume from the table to each one. 3. Transfer the stated volume of stock into tube 1 and mix well (pipette up and down or vortex). 4. With a fresh tip, move the same volume from tube 1 to tube 2, mix, and carry on down the series. Print the table and tick each tube as you go. ## Limitations - The calculation assumes perfect pipetting and mixing. Errors multiply down the series: a 2% error per step is about 10% after five steps. - Transfer volumes under about 2 µL are hard to pipette accurately; the calculator warns when you go below that. - Volumes are assumed additive, which is right for dilute aqueous solutions but not for mixing, for example, ethanol and water. - Molar ↔ mass conversion needs the molar mass of the solute. Cells, CFU, % and U/mL are scaled only in their own unit. **Making the stock first?** Work out the grams for a buffer of any pH, or the mass for a solution of given molarity. [Buffer preparation calculator](https://www.moldraw.com/tools/free-chem-tools/buffer-preparation-calculator.html) ## Frequently asked questions ### How do you calculate a serial dilution? The concentration in tube n is C0 / F^n, where F is the dilution factor per step. For each tube, transfer V/F from the previous tube into V − V/F of diluent, where V is the final volume. 1 mM diluted 1:10 five times gives 1 mM / 100,000 = 10 nM. ### What does 1:10 mean in a dilution? Here 1:10 means 1 part sample in 10 parts total (1 part sample plus 9 parts diluent), a dilution factor of 10. Some fields use 1:9 for the same thing. Check which convention your protocol uses. ### How do I find the dilution factor I need? For n equal steps from C0 to a target C, the factor is (C0/C)^(1/n). Going from 1 mM to 1 µM in 3 steps needs a factor of 10. The reverse calculator also gives the number of steps for a fixed factor. ### Why is the last tube's volume larger than the others? In a standard series every tube except the last loses a transfer volume to the next tube. Tick Equal volume left in every tube: each tube then gets V of diluent, you transfer V/(F−1), and you discard that volume from the last tube. ### Can I use mg/mL or cells/mL? Yes. The calculator works with M, mM, µM, nM, pM, mg/mL, µg/mL, ng/mL, pg/mL, cells/mL, CFU/mL, copies/µL, % and U/mL. With a molar mass it also converts between molar and mass units. ## Related chemistry tools [Dilution Calculator (C1V1 = C2V2)](https://www.moldraw.com/tools/free-chem-tools/dilution-calculator.html)[Buffer Preparation Calculator](https://www.moldraw.com/tools/free-chem-tools/buffer-preparation-calculator.html)[Solution Prep Calculator](https://www.moldraw.com/tools/free-chem-tools/solution-prep-calculator.html)[Molarity Calculator](https://www.moldraw.com/tools/free-chem-tools/molarity-calculator.html)[Beer–Lambert Law Calculator](https://www.moldraw.com/tools/free-chem-tools/beer-lambert-law-calculator.html)[Grams to Moles Calculator](https://www.moldraw.com/tools/free-chem-tools/grams-to-moles-calculator.html) Last updated: October 30, 2026