About the Bishop Score Calculator
The Bishop score (pelvic score) rates how ready the cervix is for labour. Edward Bishop introduced it in 1964 to predict the success of elective induction, and it is still the most widely used cervical assessment in obstetrics. A vaginal examination scores five features — dilation, effacement, fetal station, cervical consistency and cervical position — for a total from 0 to 13.
A low score means the cervix is "unfavourable" (closed, long, firm and posterior), and induction is less likely to lead to vaginal birth without first ripening the cervix. A high score means the cervix is "favourable" and the chance of vaginal delivery after induction approaches that of spontaneous labour. This calculator gives the total and a plain-language category so midwives, obstetricians and students can document it consistently.
Guidelines draw the line differently. The UK NICE induction of labour guideline (NG207, 2021) treats a score of 6 or less as unfavourable and more than 6 as favourable, while ACOG notes that above 8 the chance of vaginal birth after induction is similar to spontaneous labour. This calculator therefore reports 7–8 as favourable by the NICE threshold but below the ACOG one. Modified Bishop scores also vary with parity and local practice. This tool does not recommend any method of induction or cervical ripening — those decisions belong to the clinical team.
With the default inputs, the bishop score is 4 / 13. Change any value above to recalculate instantly.
How to use the bishop score calculator
- 1Perform a vaginal examination and estimate dilation in centimetres.
- 2Estimate effacement as a percentage of normal cervical length.
- 3Record fetal station, cervical consistency and position.
- 4Select each finding and read the total score and category.
Formula and method
Points: dilation closed = 0, 1–2 cm = 1, 3–4 cm = 2, ≥ 5 cm = 3; effacement 0–30% = 0, 40–50% = 1, 60–70% = 2, ≥ 80% = 3; station −3 = 0, −2 = 1, −1 or 0 = 2, +1 or +2 = 3; consistency firm = 0, medium = 1, soft = 2; position posterior = 0, mid = 1, anterior = 2. The maximum is 13.
A total of 6 or less is described as unfavourable by both NICE and ACOG. NICE NG207 treats more than 6 as favourable; ACOG describes a total above 8 as giving a probability of vaginal delivery after induction similar to spontaneous labour. The simplified Bishop score uses only dilation, effacement and station (0–9) and has shown similar predictive value in later studies; it is displayed for reference.
- Dilation
- Opening of the cervical os in cm
- Effacement
- Thinning of the cervix (%)
- Station
- Descent of the presenting part relative to the ischial spines
- Consistency, Position
- Firmness and orientation of the cervix
Worked examples
Unripe cervix at 41 weeks
Dilation 1–2 cm (1) + effacement 40–50% (1) + station −2 (1) + medium consistency (1) + posterior position (0) = 4, an unfavourable cervix.
Ripe cervix
3–4 cm (2) + 60–70% (2) + station 0 (2) + soft (2) + mid-position (1) = 9, a favourable cervix.
Intermediate score
1–2 cm (1) + 60–70% (2) + station −2 (1) + soft (2) + mid (1) = 7. That is above the NICE cut-off of 6 but not above the ACOG threshold of 8.
Frequently asked questions
What is a good Bishop score for induction?+
A score of 6 or less is unfavourable. NICE (UK) treats more than 6 as favourable, while ACOG (US) notes that above 8 induction is about as likely to end in vaginal birth as spontaneous labour.
What are the five parts of the Bishop score?+
Cervical dilation, effacement (thinning), fetal station, cervical consistency (firm, medium or soft) and cervical position (posterior, mid or anterior). Dilation, effacement and station score up to 3; consistency and position up to 2.
What is a modified Bishop score?+
Modified versions change some items — for example, replacing effacement with cervical length in centimetres — or add adjustments for parity and other factors. The simplified Bishop score uses only dilation, effacement and station.
Does a low Bishop score mean I need a caesarean?+
No. A low score means the cervix is not yet ready, so induction may take longer and the team may use methods to soften and open the cervix first. Many people with low scores still have a vaginal birth.
Who calculates the Bishop score?+
It is calculated by a midwife or doctor from a vaginal examination, usually when induction of labour is being planned or at the start of the induction process.
For healthcare professionals and education only. This calculator implements a published formula or score but is not a diagnosis and does not replace clinical judgment. Verify inputs and results against the original source before using them in patient care.