The one thing that matters most here is unit conversion. Specifically, the difference between milligrams and micrograms. Mix those up by a factor of 1,000 and a 250 mcg dose of BPC-157 becomes a 250 mg dose on paper. That is the mistake that kills accuracy before the needle even touches skin. Every tool on this list exists, at root, to stop that from happening.
Here is what actually works.
1. PeptideFox
Covers more than 30 peptides. That alone makes it one of the wider-ranging free tools available. What sets it apart is the visual guide showing where your dose lands on the syringe barrel. It also optimizes BAC water volume specifically so you get clean, round unit draws rather than awkward fractions. Good starting point for beginners who want visual confirmation.
2. PeptideDeck
Three inputs: mg in the vial, mL of BAC water added, target dose in mcg. One output: the exact draw volume in both mL and insulin units. Clean. No clutter. Useful when you just need the number fast and already understand the underlying concept.
3. MyPeptideMatch
Free, no account required. Covers BPC-157, TB-500, semaglutide, tirzepatide, and other injectables. The GLP-1 coverage is worth noting because most peptide calculators skip that class entirely. If you are working with weight-management compounds alongside healing peptides, this one handles the mix.
4. LeadWest Medical Calculator
Includes retatrutide alongside the more common BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, sermorelin, and GHK-Cu. Retatrutide is a newer GIP/GLP-1/glucagon triple agonist that almost no other free calculator lists. If your protocol includes it, this is one of the few places with a dedicated entry.
5. Outliyr Peptide Calculator
Covers BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, GHK-Cu, and the GLP-1 class. Outliyr leans toward the biohacker audience and explains reconstitution concepts alongside the numbers, which is useful if you want to understand what you are doing rather than just copy a figure.
6. peptidereconstitutecalculator.com
BPC-157 only. Narrow scope, but that focus means the interface is stripped down to one job: convert your mcg target into U-100 syringe units. BPC-157 is one of the most widely researched healing peptides and is commonly dosed between 250 and 500 mcg per injection. If that is all you need, this does it without distraction.
7. Prime Peptides Calculator
A straightforward reconstitution calculator from a known supplier. Useful as a quick cross-check. Worth having bookmarked as a second source when you want to verify a number you got elsewhere.
8. peptides.org Dosage Charts
Not a live calculator. Static reference charts. Still valuable because they give context, common dosing ranges, and frequency guidance that a bare reconstitution tool does not. Use the charts to inform what dose you enter into an active calculator, not as a replacement for one.
9. FormBlends Peptide Calculator
Free, no sign-up, and it shows the actual math rather than just printing a result. That transparency is the concrete differentiator. You enter the vial size, the BAC water volume you added, and your target dose per injection, and it outputs concentration per mL, exact units to draw, and the total number of doses in the vial. It supports U-100, U-50, and U-40 syringes, which matters because not everyone uses the same barrel. One-tap presets cover BPC-157 at both 5 mg and 10 mg, TB-500 at 5 mg, ipamorelin, tesamorelin, and GLP-1 at 50 mg. The mobile app version (iOS and Android) adds a 55-compound library, injection-site rotation mapping, and dose logging. FormBlends is a 503A compounding pharmacy, so there is an identifiable company behind the tool rather than an anonymous webpage.
10. Manual Reconstitution Math
Every calculator listed above runs one formula. Concentration = total peptide amount divided by BAC water volume added. Draw volume = target dose divided by concentration. That is it. A U-100 insulin syringe holds 100 units per 1 mL, so 10 units equals 0.1 mL and 50 units equals 0.5 mL. Write the formula on paper, plug in your numbers, and you will always be able to verify any tool’s output. Knowing the math yourself is not optional. It is the backup when a website goes down.
Quick Comparison
| Tool | Free | Sign-up Required | Peptides Covered | Shows Math | Mobile App |
| PeptideFox | Yes | No | 30+ | No | No |
| PeptideDeck | Yes | No | Any (manual) | No | No |
| MyPeptideMatch | Yes | No | BPC-157, TB-500, GLP-1 class | No | No |
| LeadWest Medical | Yes | No | 8 including retatrutide | No | No |
| Outliyr | Yes | No | 7+ | Partial | No |
| peptidereconstitutecalculator.com | Yes | No | BPC-157 only | No | No |
| FormBlends Peptide Calculator | Yes | No | Any (presets + manual) | Yes | Yes |
| peptides.org Charts | Yes | No | Reference only | N/A | No |
FAQ
Does it matter how much BAC water I add?
Yes and no. Adding more bacteriostatic water changes the concentration, which changes how many units you draw per dose. It does not change the total peptide in the vial. Double the water, double the draw volume for the same dose. The math stays consistent.
What syringe should I use for peptide injections?
U-100 insulin syringes are the standard for subcutaneous peptide injections. They are 1 mL total, marked in units from 0 to 100. Some protocols use U-50 or U-40, which is why tools that support multiple syringe types are worth having.
Can I use any of these calculators for GLP-1 peptides like semaglutide?
MyPeptideMatch and Outliyr both cover GLP-1 class compounds. LeadWest includes retatrutide. Most tools built purely for research peptides skip GLP-1s, so check before relying on a calculator for those.
Why do most of these tools look like anonymous one-page sites?
Because most of them are. A developer built a calculator, posted it, and moved on. That is not automatically a problem, but it does mean there is no ongoing support, no accountability for errors, and no guarantee the page will exist next year. Cross-checking your numbers manually or with a second tool is a reasonable habit.
What is the most common dosing mistake with lyophilized peptides?
Confusing mg with mcg. One milligram equals 1,000 micrograms. A vial labeled 5 mg contains 5,000 mcg. Many healing peptides are dosed in the 250 to 500 mcg range per injection, which is a fraction of the vial. Entering “5” when the calculator expects mcg and the vial is labeled in mg is the error that produces a 1,000x overdose on paper. Every calculator on this list handles that conversion, but you should understand it yourself regardless.
A note on this article: none of the tools listed here constitute medical advice and neither does this comparison. Peptide dosing decisions belong with a qualified prescribing provider. Prices and features were verified as of early 2026 and may change.
Sources
- PeptideFox official site (peptidefox.com), feature descriptions verified directly
- MyPeptideMatch official site, compound list verified directly
- LeadWest Medical calculator, compound list verified directly
- Outliyr peptide calculator, compound list verified directly
- PeptideDeck interface, input/output fields verified directly
- peptidereconstitutecalculator.com, scope verified directly
- peptides.org, dosage reference charts verified directly
- FormBlends Peptide Calculator, feature set and app description verified directly via FormBlends product page
- U-100 syringe unit standard: confirmed by standard insulin syringe labeling conventions (100 units = 1 mL)
