ISO 5807 / GOST 19.701-90 flowchart: the full guide
ISO 5807 (aligned with GOST/DSTU 19.701-90) defines which shapes and directions represent an algorithm — the standard graders check a diagram against. Below: every shape shown visually, a live “algorithm → chart” example, layout rules, and the common mistakes that get work sent back.
The shapes of ISO 5807
Every block on a compliant chart is one of these figures. Using the wrong shape (an action in a diamond, a decision in a rectangle) is the most common reason work is sent back.
Start and end of the algorithm.
An action, computation or assignment.
A condition with two exits, “Yes”/“No”.
Input or output (read/print).
A function or procedure call.
A jump between chart parts (A, B…).
A live example: algorithm → chart
The larger of two numbers. Notice: start/end are terminators, input/output are parallelograms, the condition is a diamond with two labelled exits, and flow goes top-to-bottom.
Figure 1 — max(a, b)
Direction & layout rules
Flow follows the default direction; arrows are required only where it differs. This keeps the chart readable without arrows on every line.
Each block has a single entry. A decision has exactly two exits, labelled “Yes”/“No” (or +/−).
Text is concise and fits inside the figure. Don’t overflow — split the action instead.
The whole chart is captioned “Figure N — name”, matching the report body.
Common review mistakes
Action in a rectangle
Action inside a diamond
Diamond only for conditions
A condition drawn as a rectangle
Start & end terminators present
Missing start/end ovals
Arrows only where direction differs
Needless bottom-up arrows everywhere
Skip the drawing — generate it
Paste code in any of 10 languages and rombik picks the correct shapes, direction and labels per the standard automatically — then exports to Word, Visio, draw.io, Typst, Excalidraw, SVG, PNG or PDF.