How to read these charts
A dosage chart is a multiplication table for one idea: the same dose takes different units depending on how much water the vial was mixed with. Each table below holds two numbers fixed and varies the third, so the effect of each input is visible on its own. All rows are arithmetic examples computed from the four formulas — concentration equals vial mg × 1,000 ÷ water mL, volume equals dose ÷ concentration, units equal volume × 100, and doses per vial equal vial mcg ÷ dose. If a row looks surprising, work it by hand from those four steps; the chart is a shortcut, not a source of authority.
Table A — 5 mg vial, 500 mcg dose, water 1–5 mL
| Water (mL) | Concentration | Volume per dose | Units (U-100) |
|---|---|---|---|
| 1 mL | 5,000 mcg/mL | 0.10 mL | 10 units |
| 2 mL | 2,500 mcg/mL | 0.20 mL | 20 units |
| 3 mL | 1,666.667 mcg/mL | 0.30 mL | 30 units |
| 4 mL | 1,250 mcg/mL | 0.40 mL | 40 units |
| 5 mL | 1,000 mcg/mL | 0.50 mL | 50 units |
Read across: more water, lower concentration, more units for the same 500 mcg dose.
Table B — 5 mg vial, 2 mL water, doses 250–1,000 mcg
| Dose (mcg) | Concentration | Volume per dose | Units (U-100) | Doses per vial |
|---|---|---|---|---|
| 250 mcg | 2,500 mcg/mL | 0.10 mL | 10 units | 20 |
| 500 mcg | 2,500 mcg/mL | 0.20 mL | 20 units | 10 |
| 750 mcg | 2,500 mcg/mL | 0.30 mL | 30 units | 6.67 |
| 1000 mcg | 2,500 mcg/mL | 0.40 mL | 40 units | 5 |
At a fixed concentration of 2,500 mcg/mL, units scale directly with the dose: double the dose, double the units.
Table C — 10 mg vial, 2 mL water, doses 250–1,000 mcg
| Dose (mcg) | Concentration | Volume per dose | Units (U-100) | Doses per vial |
|---|---|---|---|---|
| 250 mcg | 5,000 mcg/mL | 0.05 mL | 5 units | 40 |
| 500 mcg | 5,000 mcg/mL | 0.10 mL | 10 units | 20 |
| 750 mcg | 5,000 mcg/mL | 0.15 mL | 15 units | 13.33 |
| 1000 mcg | 5,000 mcg/mL | 0.20 mL | 20 units | 10 |
A 10 mg vial at 2 mL is 5,000 mcg/mL — twice as concentrated as Table B — so the same doses take half the units.
What the three tables teach together
Compare Table A with Table B and the two levers of this math separate cleanly. In Table A the dose never changes, yet the units run from 10 to 50 — the water alone moved them, because the water sets the concentration. In Table B the water never changes, yet the units run from 10 to 40 — the dose alone moved them, because at a fixed concentration, units are proportional to dose. Table C then shows the vial lever: doubling the vial at the same water doubles the concentration and halves the units for any given dose. Three inputs, three independent effects, one chain of formulas. Once that is clear, no chart is needed at all — but until it is, the tables are a faster way to build the intuition than typing numbers one at a time.
Why charts like this get searched
People search for charts for the same reason they search for calculators — they want an answer they can read at a glance and check against their own numbers. The difference is that a chart is frozen: it can only show the combinations its author chose. That is why this page pairs the tables with the live calculator above. If your numbers are not in a table, the calculator is the same math with no frozen choices.
Checking a row by hand
Take any row — for example, Table B, 750 mcg. The concentration is 2,500 mcg/mL because 5 mg is 5,000 mcg and 5,000 ÷ 2 = 2,500. The volume is 750 ÷ 2,500 = 0.3 mL. The units are 0.3 × 100 = 30. The doses per vial are 5,000 ÷ 750 = 6.67. That means 6 full doses, with 0.67 of a dose left over — not 7. The table shows the exact 6.67 so the two are never confused. Do the same check on any other row: concentration first, then volume, then units, then doses. If a row ever disagrees with your hand calculation, trust the hand calculation and re-check the inputs — the formulas are the authority, not the table.
The boundary
These tables are arithmetic examples. They do not recommend any dose, water amount, or schedule, and they must not be read as guidance about what anyone should do. Pure math only — not medical advice.