The peptide calculator that shows its work
PeptideCalc turns reconstitution and dosing math into instant, transparent answers — free, with no ads and no logins required.
Why we built a peptide calculator
PeptideCalc started with a simple frustration: every peptide calculator we tried was either buried under ads, gated behind a sign-up, or too vague to trust. When you're working with milligram-level compounds measured in insulin syringe units, you shouldn't have to guess whether the tool got the math right. So we built our own — a fast, free peptide calculator that shows its work at every step.
The tool was designed around the two calculations researchers and biohackers ask for most. As a peptide dosage calculator, it converts your target dose in milligrams or micrograms into a precise draw volume. As a peptide reconstitution calculator, it takes the amount of peptide in your vial and the volume of bacteriostatic water you add, then returns a clear concentration in mg per mL — and per syringe unit.
Everything runs instantly in your browser. There are no accounts to create, no email walls, and no premium tiers. Whether you're reconstituting a single vial or planning a multi-vial protocol, the goal is the same: fast answers you can double-check by hand in seconds.
How the calculator works
The math behind every peptide calculator is straightforward once it's spelled out. First, the tool calculates concentration: the amount of peptide in your vial (in milligrams) divided by the volume of diluent you add (in millilitres). A 5 mg vial mixed with 2 mL of bacteriostatic water gives a concentration of 2.5 mg per mL.
Next, it converts your target dose into a draw volume by dividing the dose by that concentration. A 0.25 mg dose drawn from a solution at 2.5 mg per mL means 0.1 mL of fluid in your syringe.
Finally, the calculator translates that volume into syringe units for a standard 100-unit insulin syringe, where 1 unit equals 0.01 mL — so 0.1 mL reads as 10 units on the barrel. Each step is displayed on screen so you can verify the arithmetic against your own numbers. We're not a lab or a pharmacy; we simply implement these standard formulas accurately, transparently, and without rounding surprises.
For research and educational use only
PeptideCalc is a research and educational tool, not a source of medical advice. It performs arithmetic; it does not diagnose, treat, or recommend any substance, dose, or protocol. Peptide compounds referenced in research contexts are not approved medicines in most jurisdictions, and handling them carries real risks.
If you're making decisions that affect your health, consult a qualified healthcare professional who knows your history. If you're working in a lab, follow your institution's safety and compliance procedures. Use this peptide calculator as a math aid — and treat its output as a starting point for your own verification, not a final word.
Frequently asked questions
Is the peptide calculator really free to use?
Yes. Every calculation on PeptideCalc is free and unlimited, with no account, paywall, or ad-supported upsell. We keep the tool lean so you can get an answer and get back to work.
What information do I need before calculating?
You'll need three inputs: the amount of peptide in your vial (in mg), the volume of diluent you plan to add (in mL), and your target dose (in mg or mcg). The peptide calculator handles the concentration math and unit conversions from there.
How do syringe units map to millilitres?
On a standard 100-unit insulin syringe, 1 unit corresponds to 0.01 mL. The calculator automatically converts draw volumes into units so you can read the measurement directly off the syringe barrel.
Can I use PeptideCalc for clinical dosing decisions?
No. PeptideCalc is intended for research and educational purposes only and does not provide medical advice. Anyone making health-related decisions should consult a qualified healthcare professional.