Budget Variance Explainer

Variance Analysis, Done

Know the why behind every variance, not just the number

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How to Upload a Claude Skill

Features List

3

Analysis Types

3

Output Formats

8

Root Cause Categories

Why FP&A Teams Use This Skill

Root Cause, Not Just the Gap

Most variance reports tell you T&E was $60K over budget. This skill tells you why — 12 additional trips at $5K average cost, driven by an unbudgeted sales conference in September. Three layers of driver logic cover generic categories, line-item-specific hypotheses, and cross-line-item pattern analysis. You walk into the management review with the explanation, not just the number.

Three Analysis Types in One Skill

Single period actuals vs. budget. YTD cumulative through any month. Full-year forecast vs. original budget. The skill handles all three — confirm which applies to your data, and it structures the analysis and commentary to match. No reconfiguring for different reporting cadences.

Cross-Line Patterns Caught Automatically

Revenue missed by $500K and commissions came in $45K favorable? The skill catches that pattern — volume-driven miss, not a pricing issue — and flags it in the narrative. If salary is favorable but benefits aren't moving in the same direction, it flags the anomaly for investigation. Commentary reflects the full picture, not each line in isolation.

Board-Ready Language, Not Jargon

The executive narrative leads with numbers, states specific drivers, quantifies where possible, and uses plain language. 'Marketing underspent by $150K — Q3 campaign delayed to October, $130K expected in Q4' rather than 'marketing was favorable.' Writing style guidelines are built into the skill so every output is ready for the board deck, not just the working file.

Any Input Format Accepted

Upload a single Excel file with Actual and Budget columns, two separate files you need matched, data copy-pasted from your ERP, or ask for a template to fill in. The skill normalises whatever format you provide — cleaning subtotals, mapping headers, classifying line items, and building the hierarchy — so you spend time on the analysis, not reformatting the inputs.

What You Get

Claude Custom Skill (.skill file)

The core skill file for uploading to Claude. Contains the full Budget Variance Explainer logic: 6-step workflow, 3-layer root cause engine, variance driver reference library, commentary quality standards, edge case handling, and all output format templates.
Executive Narrative Output

Board-ready paragraph commentary structured as: Overview (total variance and key drivers), Revenue Performance, Gross Margin, Operating Expenses by major category, Key Variances Requiring Attention (top 3-5 with recommended actions), Offsetting Factors, and Outlook Implications. Writing style built in: leads with the number, states the driver, quantifies, uses active voice.
Line-Item Bullet Table Output

A structured table with columns for Line Item, Actual, Budget, $ Variance, % Variance, and Commentary — one row per material variance. Formatted for quick reference in management packs. Each commentary cell quantifies the variance, identifies the specific driver, and provides timing or volume context where applicable.
Excel Workbook with Commentary Output

Four-tab Excel workbook: Summary tab (total variance, key metrics, top 5 drivers), Detail tab (all line items with Actual, Budget, $ Var, % Var, materiality flag, and commentary column), By Category tab (rollup variances by expense category), By Department tab (rollup by cost center if department data provided). Favorable variances in green, unfavorable in red, material variances bolded.
3-Layer Root Cause Engine

Layer 1: Eight generic variance categories — Volume, Price/Rate, Timing, One-time, Headcount, Efficiency, Scope Change, FX/Inflation. Layer 2: Industry-specific driver logic for Payroll, Revenue, Consulting/Professional Services, T&E, Marketing, Rent/Facilities, Technology/IT, and Depreciation and Amortization. Layer 3: Cross-line-item pattern analysis linking revenue misses to variable cost movements, headcount variances to downstream line items, and timing patterns across departments.
Variance Driver Reference Library

Pre-built commentary templates by line item type covering: Product/Service Revenue, Subscription/Recurring Revenue, Direct Materials (with price/efficiency/volume split), Direct Labor (with rate, efficiency, volume variance calculations), Salaries and Benefits, Professional Services, T&E, Marketing (campaign timing, digital, agency), Rent and Facilities, Technology/IT, and Depreciation and Amortization.
Configurable Materiality Thresholds

User-defined thresholds for flagging material variances: $ only, % only, AND (both must be met), or OR (either triggers a flag). Defaults to $10K AND 5% if not specified. The skill asks for your thresholds before analysis and applies them consistently across all line items — so your materiality standard is built into every output.
Edge Case Handling

Zero-budget line items (unbudgeted expenses flagged with commentary), negative budgets (contra-revenue with clear sign convention), missing data (flagged for user clarification rather than assumed zero), subtotal detection and exclusion (recalculated from detail lines to avoid double-counting), and mismatched cross-line variances flagged as anomalies for investigation.

When to Use This Skill

Monthly management accounts need commentary

Your month-end close is done and now you need variance commentary for the management pack. Upload the actuals vs. budget file, confirm the period and materiality thresholds, and get executive narrative and line-item bullets ready for the management review. What used to take a half-day of writing takes one conversation.

Board pack due and the CFO needs the why

The board meets in 48 hours and the CFO wants a clear explanation of the top five variances. The executive narrative output is structured for exactly this — overview first, then revenue, gross margin, and OpEx with specific root cause hypotheses, followed by items requiring attention and outlook implications. Paste it into the board pack with minimal editing.

YTD analysis before the quarterly business review

You need to explain cumulative performance through Q3 against the annual budget. Select YTD analysis, provide your cumulative actuals and budget, and the skill produces variance commentary at both line-item and rollup level — including cross-line patterns that explain whether YTD misses are volume-driven, timing-driven, or structural.

Full-year forecast vs. original budget explanation

Your 9+3 forecast differs from the original annual budget and the leadership team wants to understand why. Upload the forecast vs. budget data, select full-year analysis, and the skill generates commentary explaining the key drivers of the revised outlook — distinguishing between timing shifts (will catch up), volume changes (won't), and one-time items (non-recurring).

Department head asks why their cost centre is over

A department head has been flagged for an OpEx overspend and wants an explanation before the review. Provide the department's line-item data. The skill generates specific root cause commentary for each material variance — headcount, consulting, T&E, software — at a level of detail that's useful for the department head, not just the CFO summary.

Eight Root Cause Categories Built Into the Skill

Category	Description	Typical Lines
Volume	Activity levels different from what was planned when the budget was set	Revenue, variable COGS, commissions, shipping, usage-based costs
Price / Rate	Unit prices, hourly rates, or per-unit costs differ from budget assumptions	Revenue, direct materials, contract labor, software licenses
Timing	Spend or revenue occurred earlier or later than the period it was budgeted in	Marketing campaigns, CapEx projects, consulting engagements, deals
One-Time	Non-recurring items not included in the original budget assumptions	Severance, legal settlements, unbudgeted bonuses, event costs
Headcount	FTE count above or below budget driving payroll and associated costs	Salaries, benefits, payroll taxes, T&E, training
Efficiency	More or fewer resources consumed per unit of output than planned	Direct labor hours, raw materials usage, utilization rates
Scope Change	New initiatives added or planned activities cancelled after budget was set	Consulting projects, new hires, capital projects, product launches
FX / Inflation	Currency movements or price level changes affecting internationally exposed costs	International operations, commodity costs, imported materials

Common Questions

What data formats does the skill accept?

Does it work for single period, YTD, and full-year forecasts?

How does the root cause logic work?

What does the Excel output include?

Can I set my own materiality thresholds?

What makes the commentary quality different from writing it manually?

Stop Writing Variance Commentary. Start Explaining It.

Root cause analysis across three analysis types, three output formats, and eight driver categories. Updated for 2026.

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