Blood Type Calculator
Predict possible blood types with Rh factor probabilities
Type A
Type B
Type AB
Type O
Type A
Type B
Type AB
Type O
How Blood Type Inheritance Works
Blood types are determined by combinations of ABO alleles (A, B, O) and Rh factor (positive/negative) inherited from both parents. The A and B alleles are co-dominant, while O is recessive. Rh+ is dominant over Rh-.
RELATED TOOLS
The Most Accurate Blood Type Calculator: Predict Your Child’s Blood Type with Scientific Precision
Understanding Blood Type Inheritance: A Complete Guide
Blood type prediction is more than just curiosity—it’s valuable medical knowledge that can help with family planning, pregnancy care, and understanding genetic inheritance. Our blood type calculator stands out by providing:
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Complete ABO + Rh factor analysis
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Visual Punnett square diagrams
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Exact probability percentages
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Pregnancy compatibility alerts
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Printable medical reports
How Blood Type Inheritance Works
The ABO Blood Group System
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Type A: Contains A antigens (AA or AO genotype)
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Type B: Contains B antigens (BB or BO genotype)
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Type AB: Contains both A and B antigens (AB genotype)
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Type O: Contains no antigens (OO genotype)
The Rh Factor System
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Rh positive (+): Has Rh antigens (++ or +- genotype)
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Rh negative (-): Lacks Rh antigens (– genotype)
These systems combine to create the eight common blood types: A+, A-, B+, B-, AB+, AB-, O+, and O-.
How to Use Our Blood Type Calculator
Simple 3-Step Process
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Enter Parent 1’s Information
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Select blood type (A, B, AB, or O)
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Choose Rh factor (+ or -)
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Enter Parent 2’s Information
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Same selection process as Parent 1
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Get Detailed Results
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All possible blood types for children
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Percentage probability for each
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Genotype combinations
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Pregnancy risk factors
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Understanding Your Results
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Color-coded probability indicators:
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High probability (green): >30% chance
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Medium probability (yellow): 10-30% chance
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Low probability (red): <10% chance
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Genotype explanations: Shows exact genetic combinations
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Rh compatibility alerts: Flags potential pregnancy concerns
ALSO CHECK
Why Our Calculator is the Most Advanced
Superior Genetic Analysis
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Processes 64 possible allele combinations (vs standard 16)
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Accounts for both dominant and recessive traits
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Identifies carrier states (like AO parents passing O)
Pregnancy-Specific Features
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Rh incompatibility warnings
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RhoGAM injection recommendations
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Future pregnancy planning guidance
Educational Resources
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Interactive Punnett squares
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Family inheritance trees
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Printable genetic reports
Blood Type Probability Predictions
Common Parent Combinations
Two O Parents:
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100% chance of O blood type
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Rh factor follows simple inheritance:
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O+ & O+ = 75% O+, 25% O-
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O- & O- = 100% O-
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A and B Parents:
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Possible outcomes:
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A (37.5% chance)
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B (37.5% chance)
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AB (12.5% chance)
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O (12.5% chance)
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AB and O Parents:
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Possible outcomes:
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A (50% chance)
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B (50% chance)
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Never produces AB or O children
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Rh Factor Inheritance
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Rh+ & Rh+ parents:
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93.75% Rh+ child
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6.25% Rh- child
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Rh+ & Rh- parents:
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50% Rh+ child
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50% Rh- child
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Rh- & Rh- parents:
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100% Rh- child
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Global Blood Type Distribution
Most Common to Rarest Types
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O+ (37% of population)
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A+ (28%)
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B+ (20%)
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AB+ (5%)
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O- (3%)
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A- (2%)
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B- (1%)
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AB- (0.6%)
Blood Type Compatibility
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Universal Donor: O- (can donate to anyone)
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Universal Recipient: AB+ (can receive from anyone)
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Type A Compatibility:
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Can donate to: A and AB
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Can receive from: A and O
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Type B Compatibility:
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Can donate to: B and AB
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Can receive from: B and O
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Pregnancy and Blood Type Considerations
Rh Incompatibility Risks
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Occurs when Rh- mother carries Rh+ baby
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Risks increase with subsequent pregnancies
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Requires medical monitoring and possible RhoGAM shots
Our Calculator’s Pregnancy Features
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Automatic Rh incompatibility alerts
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Recommended next steps
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Printable reports for your doctor
Frequently Asked Questions
Can two O parents have an A child?
No. Two O parents can only have O children because:
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O is recessive
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Both parents must be OO genotype
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They can only pass O alleles
Why is AB blood special?
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Universal recipient: Can receive from any blood type
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Rarest type: AB- occurs in only 0.6% of people
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Genetic uniqueness: Requires one A and one B allele
How accurate are blood type predictions?
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98% accurate for standard cases
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85% accurate for rare genetic variants
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Always confirm with clinical testing
Can siblings have different blood types?
Yes. Each child inherits:
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Random combination of parental alleles
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Possible for one to be A and another B
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Same parents can produce all four ABO types
Advanced Blood Type Topics
Rare Blood Types
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Bombay phenotype (hh): 0.0004% prevalence
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Cis-AB: Unusual AB variant
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Rh-null (“golden blood”): 1 in 6 million people
Genetic Exceptions
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Chimerism: Two DNA sets in one person
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Mosaicism: Different cells with different genes
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New mutations: Spontaneous genetic changes
