Something shifted in 2025. Peptide use moved from obscure bodybuilding forums into telehealth clinics, and suddenly the old “just Google the math” approach wasn’t cutting it anymore. People were making 1000x dosing errors, confusing milligrams with micrograms, and drawing the wrong volume because they switched syringe types. The tools caught up. Here are the ten worth knowing about.
Quick Comparison
| Tool | Free | No Signup | Syringe Types | Peptide Presets | App (iOS/Android) | Math Shown | Dose Logging |
| FormBlends Peptide Calculator | Yes | Yes | U-100, U-50, U-40 | Yes (BPC-157, TB-500, GLP-1, more) | Yes | Yes | Yes |
| PeptideFox | Yes | Yes | U-100 | 30+ peptides | No | Partial | No |
| MyPeptideMatch | Yes | Yes | U-100 | BPC-157, sema, tirz, TB-500 | No | No | No |
| PeptideDeck | Yes | Yes | U-100 | Manual entry | No | Yes | No |
| LeadWest Medical | Yes | Yes | U-100 | BPC-157, TB-500, ipamorelin, CJC-1295, more | No | No | No |
| Outliyr | Yes | Yes | U-100 | BPC-157, TB-500, GLP-1 class, more | No | No | No |
| peptidereconstitutecalculator.com | Yes | Yes | U-100 | BPC-157 only | No | No | No |
| Prime Peptides Calculator | Yes | Yes | U-100 | Limited | No | No | No |
| peptides.org Charts | Yes | Yes | N/A | Reference only | No | N/A | No |
| MyFitnessPal (general tracker) | Freemium | No | N/A | None | Yes | N/A | Yes |
1. FormBlends Peptide Calculator
The single fact that puts this one first: it shows the actual arithmetic behind every result, so you can verify the output rather than just trust it. That matters when the difference between 250 mcg and 250 mg is a factor of one thousand.
Enter your vial amount, how much bacteriostatic water you added, and your target injection dose. It hands back the concentration per mL, the exact units to pull on your syringe, and a visual fill bar showing where that sits on the barrel. It supports U-100, U-50, and U-40 syringes, which is not common. Most tools assume U-100 and leave U-40 users guessing.
Pre-loaded quick-select entries cover BPC-157 at 5 mg and 10 mg, TB-500 at 5 mg, ipamorelin at 10 mg, tesamorelin at 2 mg, and a 50 mg GLP-1 starting point. The tool also explains, in plain text, that adding more bacteriostatic water changes the units you draw, not the total peptide in the vial. A surprising number of people get that backwards.
It does not suggest doses. You bring your prescribed dose; the tool just tells you how to measure it.
The companion app (iOS and Android) adds a 55-compound library, injection-site rotation tracking, and dose logs. Built by a company that also runs a 503A compounding pharmacy, so there is an actual organization behind it, not just an anonymous script.
2. PeptideFox
peptidefox.com covers more than 30 named peptides and includes a visual guide to BAC water volume, which helps you understand why dilution choices affect your draw. Good for people who want to see the syringe logic before committing to a protocol.
3. MyPeptideMatch
Free, no account needed, covers the GLP-1 injectables (semaglutide, tirzepatide) alongside BPC-157 and TB-500. Useful if your focus is metabolic peptides specifically.
4. PeptideDeck
You enter three numbers: vial mg, BAC water volume in mL, and target dose in mcg. It outputs concentration and the draw volume in insulin units. Clean. Minimal. The math is visible, which I appreciate.
5. LeadWest Medical
Covers retatrutide, which most of the others skip entirely. Also handles ipamorelin, CJC-1295, tesamorelin, sermorelin, and GHK-Cu. Worth bookmarking if you work with growth hormone secretagogues.
6. Outliyr
Similar peptide coverage to LeadWest, with GHK-Cu and the GLP-1 class both included. The interface is readable on mobile even though it is not a native app.
7. peptidereconstitutecalculator.com
BPC-157 only, but it does that one job well. Outputs mcg-to-units conversions for U-100 syringes. If BPC-157 is the only peptide you are working with, this is fast.
8. Prime Peptides Calculator
Straightforward web tool, limited presets. Fine for spot-checking a quick reconstitution calculation. Not much to distinguish it from the others in this tier.
9. peptides.org Dosage Charts
Not a calculator. Static reference charts for common peptides. Worth reading for context before you open any of the active tools above.
10. MyFitnessPal (General Tracker)
Included here as a comparison point only. It handles supplement and medication logging well, but it does no reconstitution math at all. Useful alongside a dedicated peptide calculator, not instead of one.
Before You Open Any of These
None of these tools prescribe anything. The reconstitution math is the same for any lyophilized peptide (vial mg divided by BAC water mL gives you concentration; your dose divided by concentration gives your draw volume in mL; multiply by syringe units per mL to get your final number), but knowing the math does not tell you what dose is right for you. Work with a qualified prescriber. These tools measure; they do not advise.
Common Questions
Does the FormBlends app work if you switch between U-100 and U-40 syringes mid-protocol?
Yes. FormBlends is one of the only tools in this list that explicitly supports U-40 alongside U-100 and U-50. You select your syringe type before calculating, so switching types recalculates the draw volume automatically. The visual fill bar updates to reflect the new barrel, which helps prevent the wrong-syringe errors that are surprisingly common when people travel or change suppliers.
Can any of these tools handle tirzepatide and semaglutide reconstitution, or are they peptide-only in the bodybuilding sense?
MyPeptideMatch covers both semaglutide and tirzepatide by name, and FormBlends includes a GLP-1 starting point preset. These are the same reconstitution mechanics as other lyophilized peptides. That said, none of the tools here set your dose. GLP-1 dosing is highly individual and should come from a prescriber, not a calculator preset.
Why does PeptideFox only show partial math while PeptideDeck shows the full calculation?
PeptideFox displays the output (draw volume, concentration) but does not walk through each arithmetic step. PeptideDeck shows the intermediate numbers. If you want to catch a typo in your own inputs, seeing the full chain of math is genuinely useful. That is one reason FormBlends and PeptideDeck rank above tools that just return a final number with no working shown.
See also: Best Stone Shop Software for Residential and Multi-Location Fabricators
Is peptidereconstitutecalculator.com worth using if I also take TB-500 alongside BPC-157?
Not on its own. That site handles BPC-157 only. For a stack that includes TB-500, you would need a second tool, or just use FormBlends or LeadWest Medical, both of which cover TB-500 natively. Running two separate calculators for a two-peptide protocol is an easy source of copy-paste errors, so a single tool that covers both is the cleaner approach.
Do any of these tools store my dose history, and should I be concerned about that data?
Only FormBlends (via the app) and MyFitnessPal offer dose logging. FormBlends is built by a company that also operates a licensed 503A pharmacy, so it has regulatory reasons to handle health data carefully. MyFitnessPal has its own privacy policy worth reading before logging anything sensitive. The web-only tools like PeptideDeck and LeadWest Medical do no logging at all, which is straightforwardly private by design.
Sources
- U-100 insulin syringe specifications: FDA insulin labeling guidance
- Peptide dosing ranges (BPC-157, TB-500): published clinical and research literature, 250-500 mcg common experimental ranges
- BAC water reconstitution principles: USP compounding standards
- PeptideFox feature list: peptidefox.com (public-facing tool, verified 2025)
- LeadWest Medical calculator: leadwestmedical.com (public tool, verified 2025)
- peptidereconstitutecalculator.com: public web tool, verified 2025
