Formulas & normal valuesFree in the app
Bedside formulas
The sums you need on the ward — each has a calculator.
Source: VariousFormula
| Naegele’s EDD | LMP + 280 days (= +9 months + 7 days); add (cycle − 28) days for long cycles. |
|---|---|
| IVF EDD | Transfer date + 266 − embryo age (day 5 → +261 days). |
| GA from CRL | 8.052 × √CRL(mm) + 23.73 = days (Robinson). |
| MAP | (SBP + 2 × DBP) ÷ 3 |
| BMI | kg ÷ m² |
| Shock index | HR ÷ SBP (normal <0.9). |
| Johnson’s EFW | (SFH − n) × 155 g; n = 13 / 12 / 11. |
| Dare’s EFW | SFH × abdominal girth (cm) = g. |
| Obstetric conjugate | Diagonal conjugate − 1.5 cm. |
| RMI I | U × M × CA-125. |
| hCG change | (hCG2 − hCG1) ÷ hCG1 × 100%. |
| Oxytocin pump | mU/min × 60 ÷ mU per ml = ml/h. |
| Bishop | Dilatation + length + station + consistency + position (max 13). |
A summary for trained clinicians. Always check the full guideline, the patient in front of you and your hospital's protocol. Spotted an error? Tell us.