Commission is total sales multiplied by the commission rate: $200,000 of sales at 10% is $20,000.00. Total gross pay adds the base salary on top: $40,000 + $20,000 = $60,000.00 a year, or $5,000.00 a month. Two operations — one multiplication, one addition — and this page shows both, annual and monthly.
The arithmetic, stated plainly
Every flat-rate commission plan reduces to the same two steps. First, the commission: the sales total the plan pays on, multiplied by the rate. Second, the total: that commission added to the fixed base salary. Nothing else is hiding in the formula — no averaging, no proration — which is why the inputs deserve more care than the math. The sales figure must be the basis the plan actually pays on. Some plans pay on gross sales booked, some on revenue actually collected, some on the profit of the sale rather than its price; the multiplication is identical in each case, but the number fed into it is not, and a rate quoted against one basis is not comparable to a rate quoted against another. The period must match, too: an annual base salary beside a quarter of sales produces a "total" that describes no real period. Keep base, sales, and the resulting totals inside one period — a year, in the worked example — and convert afterwards with the monthly rows, not before.
Worked example — $40,000 base, $200,000 of sales, 10% rate
The calculator is pre-filled with exactly this case:
- Commission earned: $200,000.00 × 10% = $20,000.00
- Total gross pay (annual): $40,000.00 + $20,000.00 = $60,000.00
- Commission per month: $20,000.00 ÷ 12 = $1,666.67
- Total gross pay per month: $60,000.00 ÷ 12 = $5,000.00
Two checks that catch most slips: the commission at a 10% rate is exactly one tenth of sales, so a misplaced decimal shows immediately; and the monthly total ($5,000.00) is the monthly base ($3,333.33) plus the monthly commission ($1,666.67), so the rows must add both across and down.
Annual and monthly — and why real months differ
The monthly rows divide the annual figures by 12, nothing more. That is the right way to compare a salary-plus-commission package against a monthly budget or a salaried offer quoted monthly — and it is not a prediction of any particular month's paycheck. Commission in practice arrives when sales close, are invoiced, or are collected, depending on the plan, so real monthly commission is uneven: heavy in the months after strong sales periods, thin in others, while the base salary arrives evenly. The annual total is the stable figure; the monthly split is that total spread evenly for comparison purposes. The same caution applies in reverse — one strong month multiplied by 12 overstates the year, which is why this page starts from period totals and divides, rather than starting from a good month and multiplying.
What a single flat rate does not cover
Many real plans are more elaborate than one rate, and this calculator's scope is worth stating rather than stretching. Tiered rates — one percentage up to a sales threshold, a higher one above it — need the sales sliced at the threshold and each slice run separately, then the commissions added; the FAQ below walks through it. Splits, where a sale is shared between two people, mean entering your share of the sales or your share of the rate, not the whole deal at the whole rate. Draws — advances paid against future commission — are not part of the commission figure at all: a draw changes when money arrives, not how much commission the sales earned, so it belongs to cash-flow timing rather than this calculation. Clawbacks and caps likewise sit outside the multiplication: commission on a sale that is later refunded or cancelled may be recovered under a plan's terms, and a capped plan stops accruing at the cap. None of those plan rules change the core arithmetic — sales × rate, plus base — they change which sales and which rate legitimately go into it.
A note on withholding
The figures here are gross. For withholding, the IRS treats commissions as supplemental wages — IRS Publication 15, §7 lists commissions in that category alongside bonuses — which means an employer may withhold federal income tax on a commission payment under the flat percentage method rather than the regular wage-table method used on salary. That is a withholding convention, not a separate tax on commission: commissions are ordinary income, the final tax on them is figured at your own rates when you file, and any difference between what was withheld and what is owed settles on the return. This site's Bonus Tax Calculator works through the flat-rate withholding method in detail, and the Salary to Hourly Calculator converts the annual total reached here into the hourly terms of a salaried comparison.