Budget Variance Calculation Explained

The budget variance formula

Dollar variance equals actual minus budget: subtract the planned (budgeted) amount from what actually happened. Percentage variance takes that same difference and divides it by the budgeted amount, then multiplies by 100.

So if a department budgeted $10,000 for the month and actually spent $11,500, the dollar variance is $11,500 minus $10,000, or $1,500 over. The percentage variance is $1,500 divided by $10,000, times 100: 15%. Both numbers matter. The dollar figure tells you the real cash impact; the percentage tells you how far off the plan was, relative to its size.

Favorable vs. unfavorable variance

Whether a variance is good news or bad news depends on whether the line is revenue or an expense, not just whether the number is positive or negative.

For revenue, actual coming in above budget is favorable: you earned more than planned. Actual coming in below budget is unfavorable. For an expense line, it flips: spending less than budgeted is favorable, and spending more is unfavorable. The marketing example above, $11,500 actual against a $10,000 budget, is an unfavorable expense variance because the department overspent its plan by 15%.

A worked revenue example

Now take a sales team that budgeted $50,000 in monthly revenue and actually closed $54,000. The dollar variance is $54,000 minus $50,000: positive $4,000. The percentage variance is $4,000 divided by $50,000, times 100: 8%. Because this is a revenue line and actual beat budget, it's a favorable variance of 8%, worth understanding (a new client, a price increase, seasonal timing) so the team can plan whether it repeats next month or was a one-time win.

How often to run the calculation

Most small businesses review budget vs. actual monthly, right after the books close for the period, and again at quarter-end for the bigger trend. Reviewing more often than monthly rarely adds insight since most expense and revenue lines don't move meaningfully week to week; reviewing less often than quarterly lets a small overrun compound before anyone notices it. The point of the review isn't to hit zero variance every time. It's catching the line that's drifting before it turns into a real cash problem, and understanding why a line moved, not just that it moved.

The same math, already running in your household budget

This isn't only a business concept. Our own household budget calculator already computes this exact calculation for you, bucket by bucket, it just doesn't use the word "variance." In that calculator's own worked example, the needs bucket runs $4,350 in actual spending against a $3,750 target: a variance of positive $600, using the identical actual-minus-budget formula above.

A household needs bucket running over its target isn't automatically bad, the same favorable/unfavorable framing applies. Needs are a cost line, so running over target is the unfavorable direction, and it's a signal to look at whether rent or insurance has grown, the same way a business would investigate an overspent department. Try the 50/30/20 budget calculator or monthly budget calculator to see your own numbers laid out the same way.

Frequently asked questions