FAST
FAST
The FAST Standard is a set of rules providing guidance on the structure and design of efficient spreadsheets.
The FAST Standard is governed by the FAST Standard Organisation.
A good financial model should be FAST:
- Flexible
- Appropriate
- Structured
- Transparent
In summary, this means you should expect:
A single workbook read from left to right
The model is designed to be read from top to bottom and from left to right.
The architecture of the model is easy to understand: for example, which calculations are exported to other worksheets.
Exceptions to model logic flow are clearly marked.
It is easy to navigate through the workbook using links
Links are used as a navigation tool: jump back on a link to arrive at a source – either a calculation on a calculation sheet or an input on an input sheet.
There is no restriction on the number of links that might point back to the same single source, but there are no links to links (“daisy chains”).
Links to other worksheets are easy to distinguish from links to the same worksheet.
Worksheets are grouped by category
Worksheets are like chapters in a book, each containing easily identifiable parts of the model.
They are arranged by category, in order: Input, Foundation, Calculation and Presentation sheets. Model logic flows from inputs to outputs via calculations.
Rows and columns have a single identifiable purpose
A column used for labels, for example, will not be used for any other purpose. Expect to find columns dedicated to labels, constants, units and row totals.
A row (also known as a line item) will have a single identifiable characteristic e.g. input, link or calculation. Its characteristic will apply to the entire row.
Calculations are presented in blocks
The calculation is at the bottom of the block with ingredients that support the calculation immediately above.
Labels, units and row totals are clearly identifiable.
There is only one calculation per block (at the bottom of the block with a blank row beneath it).
Calculation blocks are designed to be easy to read and review
The pyramid structure is designed to make each calculation block easy to read. Constants are presented above series data.
Only information relevant to the calculation is included in the block.
Calculation logic is split between (i) how much and (ii) when
The “how much” logic tends to be presented towards the top of a calculation block.
The “when” logic is modelled using a flag.
Flags are used to mask calculations that sit outside the period under consideration.
All flags are modelled on the Time sheet.
Formulas are designed to be easy to read and review
Formulas should not be longer than a thumb held against a formula bar (“the rule of thumb”).
Complex functions are used by exception only; named ranges are used by exception only.
There are no remote cell references in the formula.
Formulas are copied consistently across a horizontal timeline
To support a data series calculation, expect to see a single formula copied across the horizontal timeline. This allows a reviewer to concentrate on the first column of the timeline only (since all remaining formulas are identical to the first).
Constants are calculated in a single column and are independent of the timeline (so are not copied across).
When it comes to formulas, a reviewer only need inspect two columns: the constant column and the first column of a data series.
Financial Models
Project Finance Model Example
This is a cut-down version of the renewables template model that we use on client projects. It can be built back up to include all the items you need to satisfy investors, lenders and other stakeholders.
Corporate Model Example
This is a cut-down version of a corporate forecasting model used for business planning. The model includes functionality to present actuals followed by forecast numbers.
Further Reading
Major Exploits Affecting 2025
Master the fundamentals of financial modeling with step-by-step instructions and real-world examples.
How to build a financial model
Master the fundamentals of financial modeling with step-by-step instructions and real-world examples.
Major Exploits Affecting 2025
Master the fundamentals of financial modeling with step-by-step instructions and real-world examples.
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