Built by Sam Calder
Why this exists
InjectBuddy is built by developers, not doctors, pharmacists, or medical professionals of any kind.
Calculating the exact volume to draw from a vial is simple arithmetic (dose ÷ concentration = volume), but there was no clean, fast, no-nonsense tool to do it. Most calculator pages were cluttered, plastered with ads, required accounts, or buried the result in noise.
So InjectBuddy was built — then the peptide reconstitution calculator, because the same friction existed there, then BMI and free testosterone index, related tools people in the Testosterone (TRT) community regularly need.
All calculators perform standard mathematical operations on numbers you already have from your doctor, prescriber, pharmacist, or blood panel. Nothing more.
What InjectBuddy is
InjectBuddy is a free, browser-based calculator suite. The calculators do maths locally in your browser — your inputs are not sent to a server, and no login is needed to use them. We don't run ads or sell anything. You can optionally create an account to save your protocols and track your data; exactly what that stores, and how to export or delete it, is set out in our Privacy Policy.
It is not a medical service. It does not diagnose conditions, recommend protocols, or give medical advice of any kind. It does division and multiplication correctly and shows you the result.
Built by the InjectBuddy team — developers, not medical professionals. InjectBuddy performs standard volume and ratio calculations based on your inputs. These calculators do not constitute medical advice — always verify dosing with your prescribing doctor or pharmacist.
Who builds this
InjectBuddy is built and maintained by Sam Calder, its founder — a software developer, not a doctor or pharmacist. I built the first calculator because I needed to turn a prescription into an exact draw, and every tool I found was cluttered, ad-heavy, or wanted an account. So I made a clean one, then kept adding the calculators the Testosterone (TRT) and peptide communities kept asking for.
I’m the person accountable for the maths on this site. Every formula is standard arithmetic, verified against reference formulas and independent calculators, with the working shown on each page. If a number is ever wrong, it’s on me to fix it — email hello@injectbuddy.com and I will, promptly.
Background
InjectBuddy started with split-frequency dosing — working out what fraction of a weekly prescription goes into each injection, then converting that into milliliters on a specific vial concentration, a calculation no existing tool handled cleanly. It expanded to peptide reconstitution and GLP-1 draw volumes as the same friction appeared with different medications.
The maths is standard arithmetic, verified against reference formulas and independent calculators.
The calculators
Contact
If you find a calculation error, email hello@injectbuddy.com and we'll fix genuine errors promptly.