Growth Hormone Calculator
GH dose from body weight and indication.
About this calculator
This calculator estimates a starting daily growth hormone (somatropin) dose using weight-based rates drawn from the dosing ranges commonly cited for each approved indication. For the four pediatric/weight-based indications -- pediatric GH deficiency, Turner syndrome, small for gestational age (SGA), and Prader-Willi syndrome -- the dose is simply body weight multiplied by a fixed rate in mg/kg/day: 0.033 for pediatric GHD, 0.050 for Turner syndrome, 0.048 for SGA, and 0.030 for Prader-Willi, each a representative point within the wider ranges endocrinology references typically quote for that condition. Adult GH deficiency works differently: because adults are far more sensitive to GH and older adults especially so, adult dosing is not weight-based at all -- it starts from a fixed age-tiered daily dose (0.4 mg/day under 30, stepping down to 0.15 mg/day at 60 and older) and is then titrated against IGF-1 levels, not recalculated from the patient's weight.
The daily dose is also converted to International Units (1 mg somatropin is treated as approximately 3 IU, the commonly used approximation, though exact potency varies slightly by product) and multiplied out to a weekly total and a rough monthly cost estimate, plus how many days a 5 mg or 10 mg pen will last at that dose. What this calculator does NOT do: titrate against actual IGF-1 or GH stimulation test results, account for concurrent estrogen therapy (which raises the GH dose needed in adults), or substitute for the periodic dose adjustments an endocrinologist makes as growth velocity, weight, or lab values change over the course of treatment. It is a starting-point estimate only, not a prescription.
Medical Disclaimer
This calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making decisions about your health. Never disregard professional medical advice or delay seeking it because of results from this tool.
Inputs
Results
Daily Dose (mg)
0.99
How to Use This Calculator
- Enter the patient's Body Weight (kg) and Age (years).
- Select the Indication from the dropdown (Pediatric GH deficiency, Turner syndrome, SGA, Prader-Willi syndrome, or Adult GH deficiency).
- Review Daily Dose (mg and IU) based on weight and indication-specific dosing guidelines (Adult GHD instead uses an age-based starting dose).
- Check Weekly Dose and Estimated Monthly Cost to counsel patients on treatment burden.
- Note Days per 5 mg and 10 mg Cartridge to plan resupply intervals.
How the result changes with Body Weight
| Body Weight | Daily Dose (mg) |
|---|---|
| 15 | 0.5 |
| 23 | 0.76 |
| 45 | 1.49 |
| 75 | 2.48 |
What each input means
- Body Weight
- Patient body weight in kilograms.
- Indication
- The approved indication drives which weight-based (or, for adult GHD, age-based) dosing rate applies.
- Patient Age (years)
- Patient age. For adult GHD, starting dose is adjusted by age.
What each result means
- Daily Dose (mg)
- Recommended daily GH dose in milligrams (subcutaneous injection).
- Daily Dose (IU)
- Daily dose in International Units (1 mg ≈ 3 IU somatropin).
- Weekly Dose (mg)
- Total weekly GH dose for supply planning.
- Est. Monthly Cost ($)
- Rough cost estimate at ~$30/mg (brand pricing varies widely).
- Days per 5 mg Cartridge
- How many days a 5 mg cartridge/pen will last at this dose.
- Days per 10 mg Cartridge
- How many days a 10 mg cartridge/pen will last at this dose.
How this is calculated
Worked example, using the default values
- Identify Input ParametersBody Weight (kg) = 30, Indication (0–4) = 0, Patient Age (years) = 10 = 3 input(s) provided
- Calculate Daily DoseDaily Dose0.99 = 0.99
- Calculate Daily DoseDaily Dose = dailyDoseMg * 32.97 = 2.97
- Calculate Weekly DoseWeekly Dose = dailyDoseMg * 76.93 = 6.93
Engine last updated . Checked against 3 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why does the same body weight produce a different dose for Turner syndrome than for Prader-Willi syndrome?
Each indication uses its own weight-based dosing rate, chosen because the underlying conditions respond differently to growth hormone. Turner syndrome is dosed toward the higher end (around 0.050 mg/kg/day) because growth response in Turner syndrome tends to be more resistant to GH than idiopathic growth hormone deficiency, while Prader-Willi syndrome is dosed more conservatively (around 0.030 mg/kg/day) partly out of caution around obstructive sleep apnea risk that has been associated with GH therapy in that population.
Why doesn't body weight change the recommended dose for adult GH deficiency?
Adult GH deficiency dosing intentionally breaks from the weight-based pattern used in children. Adults, and especially older or heavier adults, are considerably more sensitive to growth hormone's side effects (fluid retention, joint pain, insulin resistance) than children are, so adult protocols instead start from a small age-tiered fixed dose and titrate it upward gradually based on IGF-1 blood levels and tolerability, rather than scaling directly with body weight the way pediatric dosing does.
How many IU is a typical pediatric GH deficiency dose?
At the calculator's default 30 kg body weight, the pediatric GH deficiency rate of 0.033 mg/kg/day works out to about 1 mg per day, which converts to roughly 3 IU per day using the approximate 1 mg = 3 IU somatropin conversion this calculator applies. Because the dose scales directly with weight for this indication, a 60 kg adolescent on the same per-kg rate would need roughly double that daily IU amount.
Is the estimated monthly cost accurate for my specific GH product?
No -- it's a rough planning figure only, built on an approximate $30-per-milligram assumption for brand-name somatropin. Actual pharmacy pricing varies widely by brand, insurance formulary tier, manufacturer copay assistance programs, and whether a biosimilar is available, so real out-of-pocket cost can differ from this estimate by a large margin in either direction.
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