The most common mistake I see people make is confusing milligrams with micrograms. It sounds obvious, but 1 mg equals 1,000 mcg, and mixing those up means drawing ten times the intended amount into a syringe. The math is simple once you slow down. These tools exist precisely so you do not have to do it in your head.
Here is how I rank the eight options worth bookmarking.
1. PeptideFox
The strongest all-around tool right now. PeptideFox covers more than 30 named peptides, and its standout feature is a volume optimization function that finds a BAC water amount that gives you clean, whole-number unit draws instead of awkward fractions. A visual guide walks you through the syringe fill. Nothing else I have tested does that optimization step automatically.
Best for: Anyone who wants pre-optimized BAC water volumes and hates drawing 0.37 mL.
Con: Web-only, no app companion.
2. FormBlends Peptide Calculator
What sets this one apart from most of the list is transparency. It shows the full math behind every output, so you can verify the concentration and units yourself rather than just trusting a black box. It defaults to U-100 syringes but also handles U-50 and U-40, which matters if you are working with older equipment. One-tap presets cover BPC-157, TB-500, ipamorelin, tesamorelin, and GLP-1 class peptides, and a visual syringe bar shows exactly where your dose falls. It is free, requires no account, and the same calculator lives inside the FormBlends mobile app alongside dose logging and an injection-site rotation tracker.
Best for: People who want to see the arithmetic, not just the answer, plus an app for ongoing tracking.
Con: Preset library is focused on the most common compounds. More obscure peptides require manual entry.
3. MyPeptideMatch
Free and surprisingly current, covering BPC-157, semaglutide, tirzepatide, and TB-500 alongside several other injectables. The GLP-1 support is the reason it makes the top three. Most peptide calculators were built for healing peptides and bolted on GLP-1s later. This one treats them as first-class inputs.
Best for: Semaglutide or tirzepatide users who want a calculator that actually knows the compound.
Con: Simpler interface with less explanatory context than some others.
4. PeptideDeck
Clean, three-field entry: vial size in mg, BAC water volume in mL, target dose in mcg. It outputs concentration, draw volume, and total doses remaining. Nothing fancy. That simplicity is a feature, not a gap.
Best for: Anyone who just wants fast math with no distractions.
Con: No presets, no visual aids. You need to already know your target dose before opening it.
See also: 168.1.8090: Connectivity and Routing Analysis
5. LeadWest Medical
The list of supported compounds here is notably specific: retatrutide, BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, sermorelin, and GHK-Cu. Retatrutide alone is reason enough to include it. Most tools do not know that peptide exists yet.
Best for: Retatrutide users and anyone working with the less common secretagogues.
Con: Narrower compound list than PeptideFox or FormBlends.
6. Outliyr
Includes built-in support for BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, GHK-Cu, and the GLP-1 family of peptides. The interface leans more editorial than purely utilitarian, which some people prefer when learning a new compound for the first time.
Best for: First-time users who want a bit of context alongside the numbers.
Con: Not designed for obscure or newer peptides outside its preset list.
7. peptidereconstitutecalculator.com
Single-purpose and proud of it. Built specifically for BPC-157, with a tight focus on converting mcg to U-100 insulin syringe units. If BPC-157 is the only peptide you are working with, this gets you an answer faster than any other option on the list.
Best for: BPC-157 only, fast lookup.
Con: Not useful for anything else.
8. peptides.org Dosage Charts
Static reference rather than an interactive calculator. No inputs, no outputs. But it is a reliable cross-check for common dosing ranges when you want a second opinion on whether a provider’s numbers are in the normal ballpark.
Best for: Sanity-checking a dose range, not calculating syringe units.
Con: You still need a separate calculator to convert anything into actual draw volume.
| Tool | Syringe Types | Presets | App |
| PeptideFox | U-100 | 30+ peptides | No |
| FormBlends | U-100, U-50, U-40 | BPC-157, TB-500, GLP-1 and more | Yes |
| MyPeptideMatch | U-100 | GLP-1 class included | No |
| PeptideDeck | U-100 | None | No |
| LeadWest Medical | U-100 | Retatrutide, sermorelin | No |
| Outliyr | U-100 | GLP-1 class included | No |
| peptidereconstitutecalculator.com | U-100 | BPC-157 only | No |
| peptides.org | N/A | Reference charts | No |
A word before you use any of these: a calculator tells you how many units to draw for a dose you already have. It does not tell you what dose is appropriate for your body, your goals, or your health history. That part requires a qualified prescriber. These are measurement tools, and treating them as anything more is where things go wrong.
Common Questions
What is BAC water, and why does the amount you add to a vial change your syringe draw so much?
BAC water is bacteriostatic water, a sterile diluent preserved with 0.9% benzyl alcohol. The volume you add sets the concentration of the reconstituted peptide. Double the BAC water and your draw volume doubles too, even though the dose in mcg stays identical. PeptideFox’s optimization feature exists specifically to find a BAC water volume that lands on a clean unit number for your target dose.
Does FormBlends actually show the math, or does it just display a final number?
It shows the intermediate steps. You can see the concentration calculation (mcg per mL), the unit conversion, and the final draw volume before you commit to anything. That distinguishes it from tools like PeptideDeck, which output only the answer. If you want to audit the result against your own arithmetic, FormBlends is the only option on this list that makes that easy.
Which calculator here is best for semaglutide, and does tirzepatide work the same way in the inputs?
MyPeptideMatch handles both as named presets rather than generic peptide entries. Semaglutide and tirzepatide are GLP-1 class compounds with their own typical vial sizes and dose ranges, and MyPeptideMatch accounts for those specifics. Tirzepatide uses the same three-field logic (vial mg, BAC water mL, target dose mcg), but having the preset avoids unit confusion between mg and mcg at the dose level.
PeptideFox covers 30-plus peptides but has no app. Is that a real limitation for daily use?
It depends on how you track doses. If you log injections in a notes app or a spreadsheet, the web tool is fine. If you want dose history, injection-site rotation, and the calculator in one place on your phone, FormBlends is the only option here that bundles all three. PeptideFox’s optimization math is genuinely better, but it stops at the calculation step.
Why would anyone use peptidereconstitutecalculator.com when the other tools also cover BPC-157?
Speed, mostly. It is a single-compound page with no dropdowns, no presets to select, and no extra fields. If you reconstitute BPC-157 regularly and already know your BAC water volume, you can get a unit number in about ten seconds. The tradeoff is total inflexibility. Add a second peptide to your stack and the tool becomes useless.
Sources
- PeptideFox tool and feature documentation, peptidefox.com (accessed 2025)
- U-100 syringe volume standards, general pharmacology reference
- peptides.org dosage reference charts (publicly available)
- MyPeptideMatch compound support list, public tool interface (2025)
- LeadWest Medical calculator, public tool interface (2025)
