Sequence Number Generator

This browser tool creates a deterministic sequence of decimal integers. You control the inclusive start and end, non-zero step, maximum quantity, zero-padding width, prefix, suffix, and output separator. It does not generate random values or evaluate expressions.

Start, end, and step are parsed as base-10 integers using JavaScript BigInt, so values can exceed the safe integer range of ordinary JavaScript numbers. Decimal points, exponent notation, hexadecimal prefixes, and embedded separators are rejected.

How generation works

The first value is start. Each subsequent value equals the previous value plus step. Generation stops when it would pass the inclusive end or when it reaches the requested quantity, whichever happens first.

A positive step requires start to be less than or equal to end. A negative step requires start to be greater than or equal to end. Step zero is invalid. The quantity is limited to 10,000 results, padding to 1,000 characters, and prefix and suffix to 200 characters each.

Padding applies to the numeric component before prefix and suffix are added. For negative values, the minus sign stays before the zeros. The available separators are a new line, comma, or no separator.

Worked example

With start 1, end 9, and step 2, padding width 3, and no prefix or suffix, the result is:

001, 003, 005, 007, 009

If quantity is set to 3, output stops at 001, 003, 005 even though the end has not been reached. With start 10, end 0, and step −3, the descending sequence begins 10, 7, 4, 1.

What the result means

The output is formatted text, not a database key allocation service. Prefix INV-, padding 6, and sequence value 42 produce INV-000042. A suffix can add a static marker, but neither prefix nor suffix changes the numeric progression.

Because output is deterministic, entering the same settings produces the same strings. The tool does not check an existing database, coordinate multiple users, reserve numbers, or guarantee global uniqueness.

Limits and data safety

Generation runs locally in the current page and does not send these field values to a SoupCalc sequence API. Still, avoid pasting secrets or personal data into prefixes and suffixes, especially on a shared device or when browser extensions are installed.

The tool supports only the visible integer-range controls. It does not support templates, dates, random strings, custom expressions, automatic uniqueness, file download, or gap detection. Copying output into spreadsheets can remove leading zeros or convert large identifiers to scientific notation; import such values as text.

Large output can consume browser memory even within the fixed cap. For production identifiers, use a transactional database sequence, UUID/ULID scheme, or another system designed for concurrency and auditability.

Sources

• ECMAScript Language Specification — BigInt — exact arbitrary-size integer semantics used by the generator.
• WHATWG HTML Standard — input controls — normative behavior for numeric constraints and form inputs used by the interface.

Editorial record

Written and behavior-checked by the SoupCalc Editorial Team. Ascending, descending, capped, out-of-direction, zero-step, negative-padding, and non-integer cases are covered by automated tests.

Last reviewed: August 10, 2026.