Peptide Dilution Calculator — solve C1V1 = C2V2 in any direction.
A free peptide dilution calculator that solves the standard laboratory dilution equation C1V1 = C2V2 in any direction. Pick a mode — final concentration, diluent volume, or dilution factor — type the three known values, and read the unknown instantly with the formula visible on the result. mg/mL and µg/mL toggle; mL and µL toggle; mass-conservation check on every result.
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Free peptide dilution calculator
Solve the standard dilution equation C1V1 = C2V2 in any direction. Switch between three modes — final concentration, diluent volume, or dilution factor — type the three known values, and read the unknown instantly with the formula and a mass-conservation check.
Result — solved variable & dilution summary
What Is the Peptide Dilution Calculator?
The peptide dilution calculator on PeptideCalculatorTools.com is the standard laboratory C1V1 = C2V2 solver wrapped in a peptide-friendly interface. A dilution adds solvent (bacteriostatic water or sterile water) to a stock solution; the peptide mass in the vial does not change, only the concentration does. The calculator handles the typical workflows: dilute to a target concentration, find the final concentration after a known diluent volume, or compute a dilution factor.
It pairs naturally with the reconstitution calculator (which sets the initial concentration) and the concentration calculator (which solves single-vial mass / volume math). For diluting two peptides to a planned ratio, use the peptide mixing calculator instead.
How to Use the Peptide Dilution Calculator
1. Pick the solve-for mode
Click Solve C2 when you know the diluent volume you added and want the resulting concentration. Click Solve V2 when you know the target concentration and want the diluent volume required. Click Solve factor when you have a target dilution factor and want the concentration it produces.
2. Type the three known values
Enter C1 in mg/mL (or µg/mL or ng/mL), V1 in mL (or µL), and the value matching your mode (V2, C2, or D). The unit dropdowns apply to each value independently and convert internally. The presets give common starting points but are user-input examples, not recommendations.
3. Read the result
The result panel shows the solved variable, the dilution factor, the diluent to add (V2 − V1), the conserved mass, and a PASS/FAIL mass-conservation check. The animated beaker visualises the relative fill ratio before and after dilution. Use Reset, Copy result, Print or Copy share link to capture the calculation.
How the Peptide Dilution Math Works
The dilution equation
C1 × V1 = C2 × V2
The total peptide mass is conserved: whatever concentration × volume you start with equals the concentration × volume you end with. C1 and C2 must use the same unit; V1 and V2 must use the same unit.
Mode A — Solve for final concentration C2
C2 = C1 × V1 ÷ V2
Example: dilute 1 mL of 5 mg/mL stock to 2 mL total. C2 = 5 × 1 ÷ 2 = 2.500 mg/mL. Diluent to add = V2 − V1 = 1 mL.
Mode B — Solve for final volume V2
V2 = C1 × V1 ÷ C2
Example: dilute 1 mL of 5 mg/mL stock down to 1 mg/mL. V2 = 5 × 1 ÷ 1 = 5 mL. Diluent to add = 5 − 1 = 4 mL.
Mode C — Solve for dilution factor D
D = C1 ÷ C2 = V2 ÷ V1
Example: a 1:10 dilution (D = 10) on 1 mL of stock gives V2 = 10 mL and diluent to add = 9 mL. D and "ratio notation" 1:D are the same thing.
Mass conservation check
m = C1 × V1 = C2 × V2
The calculator reports the conserved mass in mg (or µg) on every result and shows a PASS if both sides agree within 1 part in 10 000. If the check shows FAIL, one of your inputs has been entered in a mismatched unit.
Dilution Quick Reference
How much diluent to add to 1 mL of stock at the starting concentration C1 to reach a target C2.
| C1 (stock) | Target 5 mg/mL | Target 2 mg/mL | Target 1 mg/mL | Target 0.5 mg/mL | Target 0.1 mg/mL |
|---|---|---|---|---|---|
| 10 mg/mL | 1.0 mL → 2.0 mL | 1.0 mL → 5.0 mL | 1.0 mL → 10.0 mL | 1.0 mL → 20.0 mL | 1.0 mL → 100.0 mL |
| 5 mg/mL | 1.0 mL → 1.0 mL | 1.0 mL → 2.5 mL | 1.0 mL → 5.0 mL | 1.0 mL → 10.0 mL | 1.0 mL → 50.0 mL |
| 2 mg/mL | — | 1.0 mL → 1.0 mL | 1.0 mL → 2.0 mL | 1.0 mL → 4.0 mL | 1.0 mL → 20.0 mL |
| 1 mg/mL | — | — | 1.0 mL → 1.0 mL | 1.0 mL → 2.0 mL | 1.0 mL → 10.0 mL |
| 0.5 mg/mL | — | — | — | 1.0 mL → 1.0 mL | 1.0 mL → 5.0 mL |
Format: "1.0 mL → 2.0 mL" means start with 1.0 mL of stock and add 1.0 mL of diluent to reach a total of 2.0 mL. Always pick a target concentration that is lower than C1; raising concentration is not a dilution.
Peptide Dilution Worked Examples
Example 1 — Solve C₂ (Mathematical Example)
Stock 5 mg/mL × 1 mL → dilute to 2 mL total. C2 = 5 × 1 ÷ 2 = 2.500 mg/mL. Diluent added: 1 mL. D = 2×. Mass conserved: 5 mg.
Example 2 — Solve V₂
Stock 5 mg/mL × 1 mL → target 1 mg/mL. V2 = 5 × 1 ÷ 1 = 5 mL. Diluent added: 4 mL. D = 5×. Mass conserved: 5 mg.
Example 3 — Solve factor D
Stock 10 mg/mL × 1 mL → D = 5×. V2 = 1 × 5 = 5 mL. C2 = 10 ÷ 5 = 2 mg/mL. Diluent added: 4 mL.
Example 4 — microgram unit dilution
Stock 1 000 µg/mL × 2 mL → dilute to 5 mL total. C2 = 1 000 × 2 ÷ 5 = 400 µg/mL. Diluent added: 3 mL. Mass conserved: 2 000 µg (2 mg).
Example 5 — 1:10 serial dilution step
Stock 10 mg/mL × 1 mL → V2 = 10 mL (D = 10, C2 = 1 mg/mL). Then take 1 mL of the new solution into another 9 mL of diluent → another D = 10 step, final C2 = 0.1 mg/mL.
Common Peptide Dilution Mistakes
V2 is the total volume after the diluent is added — V1 + diluent. If you mean "add 2 mL of diluent", type V2 = V1 + 2, not V2 = 2.
If C1 is in mg/mL and C2 is in µg/mL, the formula silently gives a wrong answer. Either keep both in the same unit or use the unit toggles consistently.
A dilution can only weaken a solution, not strengthen it. If you need a higher concentration, you need to add less diluent (use the reconstitution calculator instead) or use a more concentrated stock.
A 1:10 dilution (D = 10) means 1 part stock + 9 parts diluent = 10 parts total. It is not "10 parts stock + 1 part diluent". The calculator's D field matches the C1/C2 ratio.
Peptide Dilution Calculator FAQ
What does the peptide dilution calculator do?
It solves C1V1 = C2V2 in any direction. You can find (a) the final concentration C2 after adding a diluent volume, (b) the diluent volume needed to reach a target C2, or (c) the dilution factor required to reach a target C2.
How is the final concentration calculated?
C2 = C1 × V1 ÷ V2, where V2 is the total volume after adding diluent (V1 + diluent). Example: 5 mg/mL × 1 mL ÷ 2 mL = 2.5 mg/mL.
How much diluent do I add to reach a target concentration?
V2 = C1 × V1 ÷ C2. The diluent to add is V2 − V1. Example: to dilute 5 mg/mL × 1 mL to 1 mg/mL, V2 = 5 × 1 ÷ 1 = 5 mL, so add 5 − 1 = 4 mL of diluent.
What is a dilution factor?
The dilution factor D = C1 ÷ C2 = V2 ÷ V1. A D of 5 means the solution is 5× weaker after dilution. A 1:10 dilution (D = 10) means each part stock is topped up to 10 parts total volume.
Does the calculator convert mg/mL and µg/mL automatically?
Yes. The unit toggle (mg/mL, µg/mL, ng/mL) applies to both C1 and C2. The calculator reports the result in your chosen unit and also in mg/mL for cross-checking.
Does the calculator convert mL and µL automatically?
Yes. The volume toggle (mL, µL) applies to both V1 and V2. 1 000 µL = 1 mL.
Why does mass stay the same in a dilution?
Diluting adds solvent, not peptide. The total peptide mass in the vial is conserved: m = C1×V1 = C2×V2. The calculator checks this on every result and reports the conserved mass.
Can I dilute a peptide with the same solvent it was reconstituted with?
Yes — that is the typical workflow. The dilution calculator is solvent-agnostic; it treats the diluent as a volume of liquid.
Is this calculator medical advice?
No. The peptide dilution calculator is a math tool. It does not give medical advice, recommend a dose, or model pharmacokinetics. The presets are user-input examples only.
Can I share my inputs with someone else?
Yes. Click Copy share link. The button copies a URL with your mode, C1, V1 and the target value embedded; opening that URL restores the same inputs.
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The peptide dilution calculator on this page performs mathematical conversions only. It does not give medical advice, recommend a dose for any person, or model pharmacokinetics. The preset values shown are user-input examples only, not recommended doses. Read the full medical disclaimer and the site disclaimer.