The last two years changed how people approach peptide dosing math. GLP-1 compounds like semaglutide and tirzepatide moved from niche research circles into mainstream conversation, and suddenly a lot of people who had never handled a lyophilized vial were staring at a 5 mg powder cake and a bottle of bacteriostatic water with no idea what to do next. Calculator tools multiplied fast. Quality varies enormously.
Before mapping out five real options, here are the criteria that actually matter when choosing one.
How to Pick the Right Tool
Syringe type support. Most peptide dosers use U-100 insulin syringes (100 units per 1 mL). A few use U-40 or U-50. A calculator that assumes U-100 and never tells you that will give wrong outputs if your syringe differs.
mg vs. mcg handling. This conversion trips people up more than any other part of the process. One milligram equals 1,000 micrograms. Getting this backwards by a factor of 1,000 is a serious error. Any worthwhile tool either converts automatically or makes the units impossible to confuse.
Visible math. Black-box calculators that just spit out a number without showing the formula are hard to verify. If the output looks wrong, you want to be able to check it.
Peptide-specific presets vs. universal input. Some tools cover a small fixed list. Others let you enter any vial size plus any water volume, which makes them useful for any lyophilized compound regardless of name.
Whether there is an actual organization behind it. Most of these pages are anonymous. That is not automatically a problem, but it is worth knowing.
The Five Tools
1. PeptideFox
PeptideFox (peptidefox.com) covers more than 30 named peptides and stands out for one specific design decision: it optimizes the bacteriostatic water volume you should add to produce clean, round-number unit draws. That sounds minor. It is not. Drawing 17.3 units on a U-100 syringe is genuinely harder to measure accurately than drawing 20. The site also includes a visual reference guide. Free, no login.
2. PeptideDeck
Simple inputs, clear outputs. You enter the total mg in your vial, how many mL of BAC water you added, and your target dose in micrograms. PeptideDeck returns the concentration per mL, the draw volume in mL, and the insulin unit equivalent. Nothing flashy. The layout makes it easy to re-run the calculation if you change water volume, which is useful because adding more water lowers the concentration and changes how many units you pull, without changing the actual peptide dose delivered.
3. MyPeptideMatch
This one covers BPC-157, TB-500, semaglutide, tirzepatide, and several other injectables. Free, no account needed. The coverage of GLP-1 class compounds alongside healing peptides makes it one of the broader free tools. Useful if you are working with more than one compound and want a consistent interface.
4. Outliyr Peptide Calculator
The Outliyr tool includes dedicated support for BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, GHK-Cu, and GLP-1 class peptides. The site has editorial content around each compound, so the calculator sits inside a larger information context rather than as a standalone widget. Helpful for people who want background alongside the math. The calculator itself handles reconstitution inputs the same way the others do, since the underlying arithmetic is identical for any lyophilized peptide.
5. peptidereconstitutecalculator.com
Narrower than the others. This tool focuses specifically on BPC-157 and works through the mcg-to-units conversion for U-100 syringes. If BPC-157 at standard doses (commonly 250 to 500 mcg per injection) is the only thing you are calculating, it handles the job cleanly. Not the pick if you need flexibility across multiple peptides.
A Note on LeadWest Medical and peptides.org
LeadWest Medical includes a calculator covering retatrutide, BPC-157, TB-500, ipamorelin, CJC-1295, tesamorelin, sermorelin, and GHK-Cu. It comes from a medical practice context rather than an anonymous page. Peptides.org offers dosage reference charts that function more as lookup tables than interactive calculators, but they are useful for cross-checking.
The FormBlends Peptide Calculator is worth mentioning for one specific reason: it shows the full math behind every output, which means you are not trusting a number you cannot verify yourself.
A Practical Caution
None of these tools tell you what dose to take. They only help you measure a dose you have already been given by a qualified provider. Getting the calculation right is one part of a longer process that starts with professional oversight, not a web form. If a number from any calculator looks surprising, check the mg vs. mcg input first. That is where almost every error begins.
Common Questions
Which of these calculators actually shows its math rather than just giving a number?
FormBlends is the one explicitly noted for displaying the full calculation behind every output. That matters when a result looks off and you need to trace where the number came from. PeptideDeck also returns concentration per mL alongside the draw volume, which gives you enough information to verify the output by hand.
If I am only working with BPC-157, is there any reason to use PeptideFox over peptidereconstitutecalculator.com?
Yes, one practical one. PeptideFox optimizes the BAC water volume to produce round-number syringe draws, which reduces measurement error at the point of injection. peptidereconstitutecalculator.com handles the mcg-to-units math cleanly but does not offer that optimization step.
Does any tool here handle both semaglutide and BPC-157 in the same interface?
MyPeptideMatch and Outliyr both do. MyPeptideMatch covers semaglutide, tirzepatide, BPC-157, and TB-500 without requiring an account. Outliyr adds ipamorelin, CJC-1295, tesamorelin, and GHK-Cu to the mix, making it the wider option if you are rotating through several compounds.
What makes LeadWest Medical different from the anonymous calculator pages listed here?
It comes from an identified medical practice rather than an unnamed publisher, and it covers retatrutide alongside the more common peptides, which most free tools skip. That institutional context does not change the underlying arithmetic, but it does mean there is an accountable organization behind the tool.
Can I use a U-40 syringe with any of these calculators, or do they all assume U-100?
Most assume U-100, which is the standard insulin syringe at 100 units per 1 mL. If you are using a U-40 syringe (40 units per 1 mL), the unit draw output from any of these tools will be wrong for your syringe. Check which syringe type a calculator assumes before trusting its unit readout, and convert manually if needed.
Sources
- PeptideFox, peptidefox.com (reviewed 2025)
- Outliyr, outliyr.com peptide calculator page
- MyPeptideMatch, mypeptidematch.com
- PeptideDeck, peptidedeck.com
- peptidereconstitutecalculator.com
- LeadWest Medical calculator, leadwestmedical.com
- peptides.org dosage reference charts
