--- title: "GLP-1 Dose Calculator — mg to Units | GLPMate" url: https://glpmate.me/tools/dose-calculator language: en description: "Convert a compounded GLP-1 dose to syringe units (U-100/U-40) from your vial's volume. Free, instant — confirm with your pharmacist." updated: 2026-07-24 --- Free tool · no signup # Dose calculator: mg ↔ units For vial-and-syringe users: enter your dose and your vial’s total drug and volume — read your syringe units, with the same realistic fill visual and magnifier as the GLPMate app. **Less math. More certainty.** The in-app calculator remembers your device and concentration — and logs the exact mg. [ Download on the **App Store** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-dose-calculator&adj_redirect_android=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_macos=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_windows=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235) [ GET IT ON **Google Play** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-dose-calculator&adj_redirect_ios=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_macos=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_windows=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate) GLPMate adapts to your device — this web tool covers vial + syringe. Pens, auto-injectors and tablets are handled in the app. Your medication Draw into a U-100 syringe This dose is about 25% of the vial. **12.5** units 10 mg ÷ 0.5 mL = 20 mg/mL _Draw volume_ **0.125 mL** _Doses per vial_ **4** Prescribed dose mg Vial — total drug (mg) mg Vial — fluid volume (mL) mL Syringe scale **Count vial overfill (+5%)** Compounders add ~5% extra fluid — it often yields one more dose than the label mg. Educational arithmetic, not medical advice. Confirm every conversion with your prescriber or pharmacist — especially after a vial or concentration change. On U-100 a draw over 1 mL is shown on a 2 mL syringe; on U-40 the scale runs 0–40 units per mL. ## The formula First, **concentration = vial’s total drug (mg) ÷ its fluid volume (mL)** — a 10 mg / 0.5 mL vial is 20 mg/mL. Then **units = (dose mg ÷ concentration) × the syringe scale** (100 for U-100, 40 for U-40). Example: a 2.5 mg dose from that vial → 0.125 mL → **12.5 units** → 10 mg on U-100, and the **4** vial holds such doses (5 with overfill). FAQ ## Dose-conversion questions ### How do I convert mg to units on a U-100 syringe? First get your concentration: the vial’s total drug (mg) ÷ its fluid volume (mL). Then units = (dose in mg ÷ concentration) × 100. Example: a 10 mg / 0.5 mL vial is 20 mg/mL, so a 2.5 mg dose is 0.125 mL = 12.5 units. ### What does U-100 mean? A U-100 syringe is marked so that 100 units equal exactly 1 mL. That’s why units = mL × 100 — the markings are just a finer way to read volume. A U-40 syringe marks 40 units per mL instead. ### Where do I find the vial’s total mg and volume? On the vial label or the pharmacy paperwork — the total drug (for example “semaglutide 10 mg”) and the fluid volume (for example “0.5 mL”). Concentration is the first divided by the second. If your label already prints mg/mL, enter that number as the total mg with a 1 mL volume. ### How many doses are in my vial? Divide the vial’s total mg by your dose in mg. A 10 mg vial at 2.5 mg per dose gives 4 doses. Compounded vials are usually filled with ~5% overfill, so you often get one extra — toggle it on to count it. In the app, GLPMate counts this down for you as you log each shot. ### Does this work for tirzepatide too? Yes — the math is identical for any injectable measured in mg with a known concentration. Enter your dose, the vial’s total mg and its volume, then read the units. ### Why does GLPMate double-check with a fill visual? Because unit errors are the most common compounding mistake. Seeing “12.5 units ≈ one-eighth of a 1 mL syringe” — with a magnified read of exactly where the plunger lands — catches order-of-magnitude errors before they happen. ### Is this medical advice? No — it’s arithmetic with a safety rail. Always confirm your dose and conversion with your prescriber or pharmacist, especially when anything changes: vial, concentration or dose. ## Your dose, remembered. Log it once in the app — device, concentration and mg travel with every shot. Free. [ Download on the **App Store** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-dose-calculator&adj_redirect_android=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_macos=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235&adj_redirect_windows=https%3A%2F%2Fapps.apple.com%2Fapp%2Fid6788548235) [ GET IT ON **Google Play** ](https://glpmate.go.link?adj_t=22klhq12&adj_campaign=tools-dose-calculator&adj_redirect_ios=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_macos=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate&adj_redirect_windows=https%3A%2F%2Fplay.google.com%2Fstore%2Fapps%2Fdetails%3Fid%3Dapp.eleutheromania.glpmate)