customformats.com

What It Is

Custom Formats Builder is an online scratchpad for learning, writing, and testing custom formats for Microsoft Excel and Google Sheets. It is more of a lightweight tool for advanced spreadsheet users than a traditional enterprise SaaS product. The page provides a format-code input area, formatted-output preview, cheat sheet, and examples, helping users verify display results before applying formats in actual spreadsheets.

Core Features and Modules

Its core functionality centers on Excel/Sheets custom-format syntax, covering types such as Number, Large Number, Fraction, Percent, Currency, Date, and Time. The cheat sheet lists rules for 0, #, ?, decimal points, thousands separators, percent signs, date year/month/day tokens, time hour/minute/second tokens, AM/PM, escape characters, and text quotation marks. The examples section includes common scenarios such as positive/negative signs, thousands separators, million abbreviations, hiding zero values, currency, fractions, percentages, ISO dates, elapsed time, text prefixes, scientific notation, and temperature units.

Pricing, Deployment, and Developer Information

The crawled content does not disclose any packages, paid plans, free tier, or trial policy, so its monetization model cannot be determined. Based on the description, it is an online web tool. The author states that the source code is available on GitLab and specifically notes that the formatting engine is provided by the SheetJS SSF project. The text does not indicate whether self-hosting, an API, enterprise accounts, or SLA support are available.

Pros and Cons

Its main strengths are its very focused positioning and the ability to test format codes immediately after opening the page, making it useful for learning and troubleshooting. Built-in examples and symbol explanations also lower the learning curve for understanding Excel custom formats. The limitations are also clear: the project is still in beta, and it currently lacks support for format colors, format conditions, mixed or unreduced fractions, and language code LCID. Alignment symbols such as ? and * also do not affect the actual alignment behavior of formatted cells. In addition, there is no information about enterprise software capabilities such as team collaboration, permission management, data security compliance, or customer support.

Who It’s For and Access from China

It is suitable for finance, operations, and data-analysis professionals who frequently work with Excel/Google Sheets reports, as well as individual users who need to quickly validate format codes. If an organization needs spreadsheet collaboration, access control, or compliance auditing, Microsoft Excel, Google Sheets, or other enterprise spreadsheet platforms should be considered first. The crawled text does not provide information about access from China, so the status is unknown; there is also no information about payment methods. Alternatives include Excel’s built-in custom cell formats, Google Sheets custom number formats, Exceljet tutorials, and SheetJS SSF.