Understand the relationship
The reasoning behind the result
Randomization changes assignment, not replication
The supplied group counts define the replicates to allocate. The shuffle changes their well positions while preserving every named replicate exactly once. Unassigned positions remain visible rather than receiving invented control roles.
A well is a position in this allocation, not automatically an independent biological unit. The relationship between wells, specimens and experimental units must come from the study design.
Row blocks restrict where assignments can move
Complete-plate mode shuffles all positions and assigns the supplied replicates to those positions. Row-block mode repeats the supplied group allocations in each selected row and shuffles positions separately within each row.
Blocking can keep each group represented across a known nuisance factor, but choosing a row as a block must be scientifically justified. The planner does not correct edge effects or confounding merely by producing a random-looking map.
A seed makes the allocation reproducible
The deterministic generator and Fisher–Yates algorithm use the seed plus the exact order of group input. Reusing both reproduces the same map. Changing the seed or group order may change positions while leaving allocation counts unchanged.
This is a transparent pseudorandom research-planning aid, not a validated clinical randomization service or a concealed treatment-allocation system. It supplies neither blinding nor an immutable audit trail.
Follow the numbers
Three complete row blocks
- Enter Control, A and B with two replicates each: six assignments per row.
- Use three rows on a 24-well plate. Each row receives six assignments, for eighteen occupied wells total.
- Shuffle each row independently with the same recorded generator stream; each group still has six assignments overall.
Rows A–C are occupied, row D remains unassigned, and every used row contains the complete supplied group allocation.
Quick guide
How to use this calculator
- Select plate format and complete-plate or row-block allocation.
- Enter unique group names and replicate counts; in block mode the entered counts apply to each used row.
- Enter and record a seed so the same inputs reproduce the same map.
- Inspect every well assignment and save the resulting record before using it in an experiment.
Calculation method
Calculation and interpretation
Generate an inspectable, reproducible well-assignment ledger from the experimental groups you supply.
Fisher–Yates shuffle using a recorded 32-bit pseudorandom seed; allocation counts are preserved exactly
Worked example
Three complete row blocks
Rows A–C are occupied, row D remains unassigned, and every used row contains the complete supplied group allocation.
Fisher–Yates shuffle using a recorded 32-bit pseudorandom seed; allocation counts are preserved exactly
Supported inputs
Precision and limits
Design arithmetic, not design approval
Entered allocations and counts do not establish adequate power, independent experimental units or control of confounding. Randomization must match the actual experiment and analysis; no biological procedure or treatment is selected.
Continue calculating
Related calculators
