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Excel modelling · Quick reference

Investment Banking Excel Formatting Guide

A quick reference for readable financial models: formula colours, number formats, hierarchy, units and checks.

Reviewed 2026-10-15 by Lewis Grafton

Start with colour codingOpen the checklist ↓

01 — Colour coding

Inputs, formulas and cross-sheet links

Use the formula bar and a written legend to tell reviewers where each number comes from.

The rule

Apply a written model legend consistently so reviewers can distinguish literal inputs, same-sheet calculations and cross-sheet links. Reserve warning styling for labelled review exceptions.

Excel example showing a P&L through net earnings, blue inputs, black formulas, green assumption links and a separate red review-warning legend
This P&L runs from Revenue through Net Earnings and includes a separate review-warning legend.Scroll sideways on smaller screens to see the full example.Open full size ↗
Excel assumptions for D&A, net interest expense, tax on positive PBT and the margin movement threshold, with the complete scope note
The source assumptions and their limits: tax applies only to positive PBT, and the margin threshold is an illustrative review policy.Scroll sideways on smaller screens to see the full example.Open full size ↗

Quick rules

  • Blue: literal input or assumption.
  • Black: calculation on the same worksheet.
  • Green: direct link to another worksheet.
  • Red: review warning defined in the model legend.

How to fix it

  1. Select the cell and check the formula bar: numeric inputs show a literal value; formulas show an expression beginning =. Example expressions and labels are text, not live formulas.
  2. Replace retyped assumptions with a direct reference to the source cell.
  3. Apply the model's legend across the comparable range, then test formula copy-across.

02 — Cell formatting

Numbers, percentages, multiples, negatives and zeros

Use number formats to change the display without changing the stored value.

The rule

Use consistent units and precision. Show negatives in parentheses where the house style requires it, and display numeric zero as a dash instead of typing text.

Excel example comparing stored numeric values with General and finance displays for positive, negative, zero, percentage and multiple values
Scroll sideways on smaller screens to see the full example.Open full size ↗
Excel example contrasting numeric zero with a typed dash and showing percentage and multiple formats
A typed dash can look like zero but still break calculations.Scroll sideways on smaller screens to see the full example.Open full size ↗

Quick rules

  • Match the case brief's units and precision across each comparable block; the diagnostic uses 0 decimals for money.
  • Store 5% as 0.05. The pictured one-decimal display is illustrative; current scored percentage formats commonly use 2 decimals.
  • Keep multiples numeric and add x with the number format. Current scored multiple formats commonly use 2 decimals.
  • Use parentheses for negative values and a zero-format dash. Never type a dash into a calculation cell.

How to fix it

  1. Select the full comparable range and open Format Cells (Ctrl+1 on Windows or Command+1 on macOS).
  2. Choose Number or Custom, set the required units and precision, then test positive, negative and zero values.
  3. Check the formula bar: each cell should still contain a number or formula, not display text.
Current financial-model format examples
UseStored inputFormat codeDisplayed output
Whole financialsParentheses for negatives; dash for numeric zero.1,250,000#,##0;(#,##0);-1,250,000
Negative financialsThe stored value remains negative.-24,500#,##0;(#,##0);-(24,500)
Numeric zeroThe cell still contains numeric zero.0#,##0;(#,##0);--
PercentagesThe stored value remains 0.2375.0.23750.00%;(0.00%);-23.75%
MultiplesQuoted x is display text, not part of the value.8.450.00"x";(0.00"x");-8.45x
MillionsEach trailing comma scales by one thousand.12,200,0000.0,,"m";(0.0,,"m");-12.2m

Need the syntax? Open the advanced custom number formats guide →

03 — Model layout

Headings, totals, units, dates and checks

Separate sections, totals and checks so a reviewer can scan the model before tracing formulas.

The rule

Use strong section bars, quieter subheadings, selective total borders, explicit period labels and formula-driven checks that show the measured variance.

Excel example showing after-cost EBITDA, all-period bridge variances and separate prior-year margin-change flags with full explanations
All-period EBITDA bridge variances and separate margin flags using an assumption-linked 1.0 percentage-point threshold.Scroll sideways on smaller screens to see the full example.Open full size ↗

Quick rules

  • Follow the case template for font, fills, borders, row labels, units, widths and shaded blanks; do not impose one house style on every case.
  • Align row labels, units and comparable periods in consistent columns.
  • Distinguish actual and forecast periods, and state currency and scale once per block.
  • Use borders and bold selectively; avoid boxing every cell.
  • Show OK or CHECK with the underlying variance so failures can be diagnosed.

How to fix it

  1. Label the period basis and units, then align the timeline across worksheets.
  2. Add formula-driven checks beside the relevant schedule and review the sheet at normal zoom and in print layout.

Final pass

Seven checks before handover

  1. 01Required sheets, titles and output cells remain intact; inputs, formulas, links and deliberate exceptions follow the case brief and model legend.
  2. 02Calculated outputs contain formulas and assumptions are not duplicated.
  3. 03Money, percentages, multiples, negatives and zeros use the right scale and format.
  4. 04Periods, dates, currencies and units are explicit and consistent.
  5. 05Sections, subtotals and key outputs have a restrained hierarchy.
  6. 06Checks are formula-driven, visible and show the measured variance before OK or CHECK.
  7. 07The workbook is recalculated and reviewed at normal zoom before delivery.
Advanced custom number formatsSyntax, scaling, literals, colours, conditions and tested examples.Open guide →Investment banking Excel shortcutsA print-friendly Windows and macOS keyboard reference.Open guide →Building a DCFForecast structure, unlevered free cash flow, WACC, terminal value and the equity bridge.Open guide →Three-statement modellingStatement links, working capital, PP&E, the cash flow statement, debt and balance checks.Open guide →Operating modelForecast structure, revenue build, cost structure and margins, capex, working capital drivers and scenarios.Open guide →LBO modellingSources and uses, financing structure, the debt schedule, the cash sweep, exit assumptions and returns.Open guide →Common Excel modelling errorsHardcodes, signs, broken links, references, copied formulas, formatting, checks and sensitivities.Open guide →

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