The single thing that separates a useful peptide calculator from a useless one is whether it shows you the math. Anyone can output a number. Tools that expose the arithmetic let you catch a unit conversion error before you inject a dose that’s off by a factor of 1,000.
Here are ten tools ranked on that standard and a few others.
1. FormBlends Peptide Calculator
The standout here is transparency. You plug in your vial size, the volume of bacteriostatic water you added, and your target dose per injection. What comes back is not just a syringe reading but the full concentration calculation and a visual fill bar showing exactly where on the barrel your dose sits. That last part matters more than it sounds: most dosing errors happen because someone misreads a small syringe, not because they got the math wrong in their head.
The tool handles U-100, U-50, and U-40 syringes without any extra steps, and it quietly converts milligrams to micrograms for you, which eliminates the classic 1,000x mistake that is genuinely the most common error in self-administered peptide protocols. One-tap presets cover BPC-157 in two vial sizes, TB-500, ipamorelin, tesamorelin, and GLP-1 formats. The same calculator is built into the FormBlends mobile app, which also includes a 55-compound reference library, dose logging, and an injection-site rotation map.
It is free. No account required. The company behind it runs a 503A compounding pharmacy, so this is not an anonymous side project.
Best for: Anyone who wants to verify the arithmetic, not just trust a black-box answer.
Con: Does not suggest a dose. You need a provider for that step.
2. PeptideFox
PeptideFox covers more than 30 peptides and does something few others bother with: it recommends a BAC water volume that produces clean, easy-to-read unit draws on a standard insulin syringe. The visual guide alongside the calculator helps beginners understand what they’re looking at.
Pro: Optimized water volume suggestions reduce draw-reading errors.
Con: Peptide-specific presets mean it’s less flexible with compounds outside its list.
3. MyPeptideMatch
A free calculator with solid coverage of both healing peptides and GLP-1 class compounds including semaglutide and tirzepatide. The interface is clean and the tool does not require a login.
Pro: One of the few free tools that handles GLP-1 dosing math alongside older peptides.
Con: No math shown, so you take the output on faith.
4. LeadWest Medical
LeadWest’s calculator is attached to a medical practice, which gives it a slightly more clinical framing. It covers retatrutide, BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, and GHK-Cu.
Pro: Retatrutide support is rare in free tools.
Con: Coverage is fixed to that compound list. Nothing outside it.
5. Outliyr
Outliyr runs a broad health and biohacking publication, and their calculator inherits that context. It covers BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, GHK-Cu, and GLP-1 compounds.
Pro: Good for readers already using the Outliyr site for research. Everything is in one place.
Con: The calculator is secondary to the editorial content. Hard to find on repeat visits.
6. PeptideDeck
Enter milligrams of peptide, BAC water volume, and target dose in micrograms. PeptideDeck outputs concentration, draw volume, and the equivalent insulin units. Straightforward and fast.
Pro: Clean three-field interface. Minimal friction.
Con: No presets, no visual syringe aid. Purely arithmetic output.
7. PeptideReconstituteCalculator.com
Narrow by design. This tool focuses on BPC-157 specifically, converting micrograms to U-100 insulin syringe units. If BPC-157 is all you need, it does that one job without any clutter.
Pro: Zero confusion. One peptide, one syringe type, one answer.
Con: Useless for anything outside BPC-157 and U-100 syringes.
8. Prime Peptides Calculator
Prime Peptides includes a dosing calculator as part of their vendor site. Functional for customers already purchasing there.
Pro: Convenient if you’re already on the site.
Con: Tied to a vendor. Independent verification is harder to establish.
9. Peptides.org Dosage Charts
Static reference material rather than an interactive tool. Peptides.org publishes fixed charts with common dosing ranges and reconstitution examples for several well-studied peptides.
Pro: Good for cross-referencing a dose range before you calculate.
Con: Static charts require you to do your own math for any non-standard vial size.
10. Manual Spreadsheet (Community-Built)
Various forums and Discord servers share Google Sheets built on the standard reconstitution formula: (vial mg x 1000) / BAC water mL = mcg per mL. Crude but the math is fully visible.
Pro: Completely transparent. Every cell is auditable.
Con: No validation, no updates, and no one is responsible for errors.
| Tool | Free | Math Shown | Multi-Syringe | App |
| FormBlends | Yes | Yes | Yes | Yes |
| PeptideFox | Yes | No | No | No |
| MyPeptideMatch | Yes | No | No | No |
| PeptideDeck | Yes | Partial | No | No |
| Outliyr | Yes | No | No | No |
A note on all of these tools: they calculate how to measure a dose you have already been given by a qualified provider. None of them tell you what dose to take. That distinction is not a legal formality. It is actually the point.
Common Questions
Why does the FormBlends calculator show the full arithmetic when most others just give you a number?
FormBlends is built by a 503A compounding pharmacy, so the product reflects how clinical staff actually think about reconstitution errors. Showing the concentration step and the visual fill bar is a direct response to the fact that syringe misreads, not formula mistakes, cause most real-world dosing errors. The math display is a feature, not padding.
If I’m only working with BPC-157 and a U-100 syringe, is there any reason to use anything other than PeptideReconstituteCalculator.com?
Practically speaking, no. It does one thing and does it without distraction. The only reason to reach for a broader tool like FormBlends or PeptideDeck is if you ever change vial sizes, switch syringe types, or add a second compound. For a single-peptide, single-syringe protocol, the narrow tool wins on simplicity.
What makes the PeptideFox water volume recommendation actually useful compared to just entering any BAC water amount?
When you reconstitute with a volume that produces awkward draws, like 0.03 mL on a U-100 syringe, small measurement errors become large percentage errors. PeptideFox’s suggested water volume is chosen so your target dose lands on a clean unit mark, which meaningfully reduces the chance of a misread. That is a real engineering decision, not a cosmetic one.
Can I use MyPeptideMatch for tirzepatide and semaglutide calculations the same way I would for BPC-157?
The math is identical across all reconstituted peptides: vial content divided by diluent volume gives concentration, and target dose divided by concentration gives draw volume. MyPeptideMatch applies that formula to GLP-1 compounds as well as healing peptides. The limitation is that it does not show the intermediate steps, so if the output looks wrong you have no way to spot where the error is.
Are community-built spreadsheets actually reliable enough to use, or is the manual formula approach just for people who distrust every other tool?
The formula itself is not in dispute. It is the same one every tool on this list uses. The risk with shared spreadsheets is that a previous user may have hardcoded a value, broken a cell reference, or simply made a typo that no one caught. They are fine for understanding the math. For regular use, a validated tool with input checking is safer, because it will at least reject nonsensical entries like a negative volume.
Sources
- U-100 insulin syringe standard: FDA insulin syringe labeling guidance (public)
- BPC-157 and TB-500 typical dosing ranges: peer-reviewed pharmacology literature and clinical compounding references
- Reconstitution formula: standard lyophilized peptide handling guides from compounding pharmacy references
- Tool feature details: direct review of each public-facing web tool, verified January 2026
