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Calcimator

Bishop Score Calculator

Calculate the Bishop score to assess cervical readiness for labor induction based on dilation, effacement, station, consistency, and position.

About this calculator

The Bishop score, described by Edward Bishop in 1964, predicts whether an induced labor is likely to succeed by scoring five features of the cervix on exam. Three of them -- Dilation, Effacement, and Station -- are scored on a wider 0-3 point scale, while Cervical Consistency and Cervical Position are capped at a narrower 0-2 points each, so a full swing in Dilation alone can move the Total Score by 3 points, one more than Consistency or Position can move it (2) on their own. The five scores sum to a maximum of 13, matching the original 1964 scoring system exactly.

A Total Score of 8 or higher is the cutoff most modern obstetric references treat as a "favorable" cervix, with induction success rates comparable to spontaneous labor; scores in the 6-7 range are intermediate and may benefit from cervical ripening before induction; and scores below 6 point toward an unfavorable cervix, where ripening agents are typically considered first. The induction-success percentages this calculator shows alongside the score are illustrative estimates that track the same general trend reported across the induction literature -- higher score, higher success rate -- rather than figures pulled from one specific published study, so they should be read as directional guidance, not a precise probability for an individual patient.

Inputs

Results

Bishop Score

0/ 13

Cervical Favorability

1(1=Unfavorable, 2=Intermediate, 3=Favorable)

Induction Success Rate30%

Figures current as of 1964. Source: Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol. 1964;24:266-268.

How to Use This Calculator
  1. Score cervical dilation, effacement (%), station, consistency, and position.
  2. Review Bishop Score — ≥ 8 predicts favorable response to induction; < 6 suggests cervical ripening first.
  3. Use in the context of gestational age, indication for induction, and full clinical assessment.

What each input means

Dilation
0 = Closed, 1 = 1-2 cm, 2 = 3-4 cm, 3 = ≥5 cm.
Effacement
0 = 0-30%, 1 = 40-50%, 2 = 60-70%, 3 = ≥80%.
Station
0 = -3, 1 = -2, 2 = -1/0, 3 = +1/+2.
Cervical Consistency
Select cervical consistency.
Cervical Position
Select cervical position.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Dilation = 0, Effacement = 0, Station = 0, Cervical Consistency = 0 = 5 input(s) provided
  2. Calculate Bishop Score
    Bishop Score
    0 = 0
  3. Calculate Cervical Favorability
    Cervical Favorability
    1 = 1
  4. Calculate Induction Success Rate
    Induction Success Rate
    30 = 30%

Figures and sources

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 is the maximum possible Bishop Score 13, not an even number like 10 or 15?

The five components don't share the same point range: Dilation, Effacement, and Station are each scored 0 to 3 points, while Cervical Consistency and Cervical Position are each scored only 0 to 2 points. Summed at their maximums, 3+3+3+2+2 equals 13 -- matching Edward Bishop's original 1964 scoring system exactly.

What Bishop Score is considered favorable for labor induction?

Most modern obstetric references treat a Total Score of 8 or higher as favorable, with induction success rates comparable to spontaneous labor onset. Scores of 6-7 are intermediate and may benefit from cervical ripening first, and scores below 6 suggest an unfavorable cervix where ripening agents are typically considered before induction is attempted.

How precise are the induction success percentages this calculator shows?

They are illustrative estimates, not a number pulled from one specific published study -- read them as directional guidance (a higher Bishop Score tracks a higher chance of a successful induction) rather than a precise probability for any one patient. Individual outcomes depend heavily on parity, indication for induction, and the induction method used.

Does Dilation matter more to the Total Score than Cervical Consistency?

Structurally, yes: Dilation is scored on a wider 0-3 point scale, so moving it from its lowest to its highest option can raise the Total Score by 3 points, one more than Cervical Consistency's 0-2 point scale allows (a maximum swing of 2). Effacement and Station share Dilation's wider 0-3 range and carry the same maximum influence.

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