Dose calculator

Semaglutide dose calculator

Convert any Semaglutide dose into syringe units in real time, pre-filled with a 5 mg / 2 mL example.

iPhone · Free to download

Last updated: May 13, 2026

Vial (mg)

Diluent (mL)

Dose (mg)

Dose unit

Draw on a U-100 syringe

10.0 units

Volume to draw

0.100 mL

Semaglutide is a once-a-week injection people use to lose weight and steady blood sugar. It mimics a gut hormone called GLP-1, which makes you feel full sooner and slows how fast your stomach empties. In the STEP-1 trial, adults without diabetes lost about 14.9% of their body weight over 68 weeks on the highest dose. This page covers the reconstitution math and how people log each weekly dose.

How the Semaglutide dose calculator works

Semaglutide doses live in a tiny range — most weekly steps land between 0.25 mg and 2.4 mg. That means you're drawing 10 to about 100 units on a U-100 syringe, which is the easiest range to read. Type your titration step and the calculator shows the exact units before you draw.

The formula is volume in mL equals dose mg divided by concentration mg/mL, then volume times one hundred to get units on a U-100 insulin syringe. With a 2.5 mg/mL Semaglutide solution and a 0.25 mg dose, the draw is 0.10 mL or about 10 units. Type any other dose and the unit count updates in real time — no spreadsheets, no guesswork.

Inputs that genuinely matter: concentration (which only changes when you reconstitute a new vial) and dose mass. Syringe type matters too, but only because U-100 vs U-40 changes the multiplier — almost every modern insulin syringe is U-100, which is why the math defaults to that. Edge cases worth flagging: switching from mcg to mg without checking the input unit, or carrying yesterday's unit count over to a new vial that was reconstituted with a different volume of BAC water.

Worked example

Walking one Semaglutide dose through the math

The vial holds 5 mg of Semaglutide, mixed into 2 mL of bacteriostatic water — concentration 2.50 mg/mL.
Your 0.25 mg dose ÷ 2.50 mg/mL = 0.100 mL of solution to pull.
Multiply by 100 (because U-100 means 100 units per mL): 0.100 × 100 = 10 units.
Double the dose to 0.5 mg and the unit count doubles to 20 — the relationship is linear at a fixed concentration.
Change the diluent volume and every one of these numbers moves; change the dose alone and only the last one does.

Semaglutide titration ladder at this concentration

What different Semaglutide dose steps draw on a U-100 insulin syringe at the example 2.50 mg/mL concentration.

Dose (mg)	Volume (mL)	Units (U-100)
0.125	0.050	5
0.25	0.100	10
0.5	0.200	20
1	0.400	40

Doubling the Semaglutide dose doubles the unit count. Halving it halves the count. Step-ups under 5 units are hard to read accurately — re-reconstitute with more water if your titration hits that range.

Scenarios people actually run into

Three things that come up logging Semaglutide

You're sitting at the 0.25 mg Semaglutide step and your prescriber bumps you up. The new dose is double — 20 units instead of 10. Same vial, same syringe, twice the volume on the line.
Your fingers reach for the syringe and the unit count from last week is still in your head. Half the time that number is fine; the other half, the vial changed and the right answer moved. The calculator is the second pair of eyes.
You skipped a week. Semaglutide cadence is 1 dose per week, and doubling up to "catch up" almost never reads how people expect — log the skip, then log the next normal dose.

Same-category neighbor

Semaglutide next to Tirzepatide

Both sit in the GLP-1 bucket — here's the dose math side by side on each one's example vial.

	Semaglutide	Tirzepatide
Example dose	0.25 mg	2.5 mg
Concentration	2.50 mg/mL	5.00 mg/mL
Units to draw	10	50

Want the full breakdown? Tirzepatide reference →

How Semaglutide dosing is tracked

Weekly dosing is the default cadence for semaglutide because of its long half-life. Each injection is a small subcutaneous draw, almost always measured on a U-100 insulin syringe rather than a tuberculin syringe, because the volumes involved are very small.

Many semaglutide protocols start with a low weekly dose and escalate gradually over several weeks or months to reduce gastrointestinal side effects. Tracking that escalation accurately is one of the main reasons people move away from notes apps and toward a structured dose log: the cumulative pattern over months is what matters, and a pattern is hard to read from scattered text notes.

Skipped or delayed doses are recorded as deliberately as taken doses in most well-run logs, because gaps in the schedule meaningfully change the next week's planning. A vial-aware tracker also flags when the current vial is approaching empty so the next vial can be ordered in time, given semaglutide's typical four-to-six-week shipping windows.

When individuals plan to document a titration schedule observed in research studies, the core logging task becomes tracking the dose changes. A typical study protocol might involve starting at a low dose and stepping up that dose every four weeks. From a data-logging perspective, the calendar dates of these transitions are the most pivotal entries. Without a clear record of when the dose was increased from 0.25 mg to 0.5 mg, for example, it becomes impossible to later parse subjective or objective data and accurately attribute it to a specific dosage period. Therefore, a robust log must cleanly delineate each dosing chapter defined by the titration points.

Common Semaglutide dose-calculation mistakes

Increasing the dose without writing down the date, then losing track of when the escalation began.
Failing to account for the cumulative effect of a long half-life, where each new weekly dose builds upon the concentration remaining from previous weeks.
Neglecting to log the precise calendar date of a dose titration, which makes it impossible to accurately correlate tracked metrics with the corresponding dose level.

Frequently asked questions about Semaglutide dose calculator

How does the Semaglutide dose calculator turn mg into syringe units?

It runs two divisions in sequence. First it computes concentration (vial mg ÷ diluent mL) — for the example here that's 5 ÷ 2 = 2.50 mg/mL. Then it divides your dose by that concentration to get volume in mL, and multiplies by 100 to convert volume into U-100 syringe units. The output updates as you type so you can sanity-check before drawing. Semaglutide titration steps usually move every 4 weeks, so each step gets logged 3-4 times before changing.

Does the Semaglutide dose calculator know which syringe I'm using?

It assumes a U-100 insulin syringe — the most common type for sub-cutaneous peptide injections. U-100 means 100 units per mL. If you're using a U-40 syringe (rare outside veterinary contexts) the unit count is wrong by a factor of 2.5. Tuberculin syringes read in mL directly, so on those just use the volume figure. Semaglutide titration steps usually move every 4 weeks, so each step gets logged 3-4 times before changing.

Why does the same Semaglutide dose pull a different unit count today than last week?

Because either the vial or the diluent volume changed. Concentration depends on both. A 5 mg vial reconstituted with 1 mL is twice as concentrated as the same vial with 2 mL — same dose, half the units. Whenever you open a fresh vial, run the dose math again rather than carrying the prior count over. Semaglutide titration steps usually move every 4 weeks, so each step gets logged 3-4 times before changing.

What if my Semaglutide dose lands at fewer than 5 units?

That's the calculator telling you the current vial is too concentrated for the dose you want. Five units on a U-100 syringe is hard to read accurately — the markings get tight. Reconstitute the next vial with more bacteriostatic water (commonly 2 mL instead of 1 mL) so each dose covers a larger, cleaner volume. Semaglutide titration steps usually move every 4 weeks, so each step gets logged 3-4 times before changing.

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