Plug in the deal and your rate to find out, roughly, before the check lands.
The commission in your plan and the money that hits your account are further apart than most sellers expect, especially the first time.
The percentage you set aside is a planning buffer, not a withholding rate. For commissions paid separately from salary, the IRS lets employers withhold federal income tax at a flat 22% (up to a million dollars a year), and payroll taxes and state withholding come on top of that, so a W-2 check often lands with roughly 30% gone. High earners tend to owe closer to 40% once the year is reconciled. A 1099 contractor has nothing withheld and should set aside 20% or more. Your real number depends on your state, your filing status and everything else you earned this year, which is why the field is editable.
Use it to plan, not to argue with payroll. Then ask the better question: is the comp plan itself sane? That's Quota Check.
Useful things for the weeks when the deal, the number, or both are giving you trouble: pipeline math, a deal that went quiet, a discount request, and what to tell your manager.
I spent six years leading federal partner sales teams at Amazon, after plenty of years carrying a number myself. QuotaBird is mostly stuff I wish we'd had back then. Most of it's free. If the problem's messier than a little tool can handle, we can talk it through.