How this instrument works
Adderall (mixed amphetamine salts) is a Schedule II controlled substance prescribed for ADHD and, less commonly, narcolepsy. The FDA-approved prescribing information specifies a fixed starting dose by formulation — immediate-release (IR) or extended-release (XR) — and by age group. This calculator looks up that one number: the dose a prescriber typically starts a patient on before any adjustment.
Immediate-release Adderall starts at 2.5 mg/day for children ages 3-5, and at 5 mg once or twice daily for ages 6 and up, including adults; from that starting point, IR is typically titrated upward by 5 mg at weekly intervals, under a prescriber's supervision, toward a commonly cited maximum of 40 mg/day. Extended-release Adderall XR starts at 10 mg once daily for ages 6-12 and for ages 13-17, and at 20 mg once daily for adults — XR isn't typically started in children under 6, so this calculator doesn't offer that combination.
This tool is scoped narrowly on purpose: it reproduces only the FDA label's starting-dose figure, not the titration schedule, maximum dose, or any of the individualized judgment a prescriber applies over the following weeks. It exists as a quick reference for clinicians and prescribers, not as a guide for starting, adjusting, or continuing this medication without a valid prescription and direct medical supervision — Adderall carries a real risk of misuse, dependence, and cardiovascular and psychiatric side effects that only a prescriber managing an individual patient's full history is positioned to weigh.
- Select the formulation: immediate-release (IR) or extended-release (XR).
- Select the patient's age group: 3-5 years, 6-12 years, 13-17 years, or Adults 18+.
- Read the FDA-labeled starting dose in mg/day.
- Note: XR paired with ages 3-5 is not offered, since extended-release isn't typically indicated under age 6 — a prescriber should be consulted for that age group regardless of formulation.
Worked example — three starting doses
A 4-year-old starting immediate-release Adderall (formulation: IR, age group: 3-5 years) has a labeled starting dose of 2.5 mg/day — the lowest starting figure on the label, reflecting how young the age group is.
An adult starting immediate-release Adderall (formulation: IR, age group: Adults 18+) has a labeled starting dose of 5 mg/day, typically given once or twice daily and then titrated upward by a prescriber in 5 mg increments at roughly weekly intervals if needed.
An adult starting extended-release Adderall XR instead (formulation: XR, age group: Adults 18+) has a labeled starting dose of 20 mg once daily — four times the IR adult starting dose, because XR is a different formulation with its own labeled starting point, not a direct conversion from the IR number.
Questions
Why can't I select extended-release (XR) for ages 3-5?
Adderall XR isn't typically indicated for children under 6 — the FDA label's XR dosing information starts at age 6. This calculator blocks that combination rather than showing a number that doesn't exist on the label; a prescriber evaluating a child under 6 would use immediate-release dosing information instead, or a different treatment approach entirely.
Does this calculator tell me how to adjust my dose over time?
No. It reproduces only the fixed starting dose from the FDA label. Ongoing dosing — whether and how much to increase, how often, and up to what ceiling — is an individualized decision a prescriber makes based on response and side effects, and is explicitly outside what this tool covers.
Is this calculator meant for patients to dose themselves?
No. Adderall is a Schedule II controlled substance available only by prescription, and starting or changing a dose without a prescriber's direct supervision carries real risks, including misuse, dependence, and cardiovascular or psychiatric effects. This tool is a quick reference for clinicians and prescribers checking the labeled starting figure, not a self-dosing guide.
Why is the immediate-release adult starting dose lower than the extended-release one?
IR and XR are different formulations with separate FDA-labeled starting doses, not scaled versions of each other. IR starts at 5 mg for adults because it's typically dosed once or twice a day and titrated gradually, while XR starts at 20 mg once daily because it releases the medication over a longer period. The two numbers aren't meant to be compared as equivalent starting exposures.
What's the maximum Adderall dose?
For immediate-release Adderall, a commonly cited maximum is 40 mg/day, reached through gradual, prescriber-directed titration from the starting dose — but this calculator doesn't calculate or display maximum or titrated doses, only the FDA-labeled starting figure. Maximum dosing varies by formulation, age, and individual response, and should come from a prescriber.
What source is this starting-dose figure based on?
The FDA-approved prescribing information for Adderall (immediate-release) and Adderall XR (extended-release), which lists starting doses by age group for each formulation. This calculator reproduces only that starting-dose table, not the full prescribing information's titration, warnings, or contraindication sections.
References
- FDA — Adderall (immediate-release) Prescribing Information (DailyMed)
- FDA — Adderall XR (extended-release) Prescribing Information (DailyMed)
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.