Variance Analysis Guide

Without variance analysis, a P&L is just a list of numbers. Variance analysis transforms it into a story: "Revenue was £45,000 above budget because the sales team closed two deals that were expected in Q2 early. OpEx was £28,000 over budget because we hired the new data engineer a month ahead of plan." This narrative drives better decisions.

A favourable variance increases profit; an unfavourable variance decreases it. For revenue lines, actual > budget is favourable. For cost lines, actual < budget is favourable. Be careful with sign conventions — inconsistent signs are the most common source of confusion in variance reporting. Establish a convention (positive = favourable, negative = unfavourable) and stick to it across all reports.

You can calculate variances against multiple benchmarks. Budget variance shows performance against the original plan. Forecast variance shows performance against the latest expectation. Prior year variance shows year-on-year change. Each serves a different purpose, and a good monthly report includes at least budget and forecast variance.

Price variance measures the impact of selling at a different price than budgeted. Formula: (Actual Price - Budget Price) x Actual Volume. If you budgeted to sell widgets at £100 each but actually sold them at £95, and you sold 1,000 units, the price variance is (£95 - £100) x 1,000 = -£5,000 unfavourable. Price variances often indicate competitive pressure, discounting, or mix shift.

Volume variance measures the impact of selling a different quantity than budgeted. Formula: (Actual Volume - Budget Volume) x Budget Price. If you budgeted 1,000 units but sold 1,100, at a budget price of £100: (1,100 - 1,000) x £100 = +£10,000 favourable. Volume variances often relate to demand, sales effectiveness, or market conditions.

Mix variance captures the impact of selling a different proportion of products or services than budgeted. If your premium product has a 60% margin and your standard product has a 40% margin, selling more standard and less premium will create an unfavourable mix variance even if total volume hits budget. Mix variance is particularly important for businesses with multiple products or customer segments.

For UK businesses with international revenue or costs, FX variance isolates the impact of currency movements. Formula: (Actual Rate - Budget Rate) x Actual Foreign Currency Amount. If you budgeted USD revenue at 1.27 GBP/USD but the actual rate was 1.22, that strengthening of sterling creates an unfavourable FX variance on your GBP-reported revenue.

Variance (£) = Actual - Budget. Variance (%) = (Actual - Budget) / Budget x 100. For revenue, a positive variance is favourable. For costs, reverse the sign: a negative variance (actual < budget) is favourable for costs.

Budget revenue: £500,000. Actual revenue: £475,000. Revenue variance: -£25,000 (-5.0%) unfavourable. Budget headcount cost: £320,000. Actual headcount cost: £298,000. Headcount variance: +£22,000 (6.9%) favourable (under-spend). Budget EBITDA: £80,000. Actual EBITDA: £77,000. EBITDA variance: -£3,000 (-3.8%) unfavourable.

Total revenue variance of -£25,000 can be decomposed. Price variance: customers received an average 3% discount versus budget, contributing -£15,000. Volume variance: 2 fewer enterprise deals closed than planned, contributing -£20,000. Mix variance: higher proportion of annual contracts (which are discounted) versus monthly, contributing -£5,000. Offset: existing customer expansion was £15,000 above budget. Total: -£25,000. This decomposition tells a much richer story than the single number.

In Grove FP, variance calculations are automatic. Actuals flow in from your accounting system, and the platform calculates absolute variance, percentage variance, and highlights material items. No manual spreadsheet updates, no formula errors, no version confusion.

A common framework uses dual thresholds — both absolute and percentage. A variance is material if it exceeds either threshold. For a company with £5M annual revenue: revenue line items might use £10,000 or 5%, whichever is lower. Operating expense categories might use £5,000 or 10%. Below-the-line items (interest, tax) might use £2,000 or 5%. These thresholds should be reviewed annually as the business scales.

Apply a simple traffic light to every variance. Green: within threshold, no action required. Amber: exceeds threshold by up to 2x, requires explanation in the commentary. Red: exceeds threshold by more than 2x, requires root cause analysis and an action plan. This system ensures that management reports focus on the items that need attention.

Investigating a £500 variance on a £200,000 budget line is a waste of time. But investigating a £500 variance on a £2,000 budget line (25% over) may be worthwhile. Context matters: a 25% variance on a discretionary spend line might indicate a process issue. The same 25% on a line with known seasonality might be expected. Use judgement alongside thresholds.

Start with the variance and ask "why" five times. Revenue is £25,000 below budget. Why? Two enterprise deals slipped. Why? The procurement process took longer than expected. Why? The customer required additional security documentation. Why? Our SOC 2 report was not ready. Why? The audit was delayed due to a change in auditor. The root cause — delayed SOC 2 audit — is actionable. The surface symptom — missed revenue — is not.

Most variances fall into one of four categories. Timing: the revenue or cost is expected but arrived in the wrong period. Volume: more or fewer transactions than planned. Rate: the price per unit differed from budget. One-off: an unexpected, non-recurring event. Timing variances often self-correct in future periods. Volume and rate variances signal trends that may persist. One-offs should be isolated and excluded from run-rate analysis.

Record your root cause analysis in a consistent format: variance amount, category (timing/volume/rate/one-off), root cause description, expected persistence (will this continue?), and recommended action. This creates an institutional memory that makes future analysis faster. In Grove FP, you can attach commentary directly to each variance, creating a permanent audit trail that carries forward month to month.

A good monthly variance report has four sections. The executive summary (half a page) covers the headline numbers: revenue, gross margin, EBITDA, and cash, each with variance to budget and forecast. The detailed P&L shows every line item with actual, budget, variance (£), and variance (%). The commentary section explains every material variance using the root cause framework. The action plan lists specific actions arising from the analysis.

Good commentary is specific, forward-looking, and actionable. Bad: "Marketing was over budget." Good: "Marketing was £12,000 (15%) over budget due to the unplanned sponsorship of TechConf (£8,000, one-off) and higher-than-expected LinkedIn CPC rates (£4,000, expected to persist). We recommend reallocating £4,000 from the Q2 events budget to cover the ongoing digital spend increase."

Every material unfavourable variance should have an owner and an action. If revenue is trending below budget, what is the sales team doing differently? If headcount costs are above budget, is the hiring plan being revised? Create a variance action tracker with columns for: variance item, root cause, owner, action, deadline, status. Review this tracker monthly alongside the variance report. The tracker creates accountability and ensures that variance analysis leads to improvement, not just explanation.