Free tool
Form field payback calculator
“Every field you add costs you conversions” is the oldest rule in form design and one of the least evidenced. This tool does not assume a number for you. You supply what you think the field will cost in completions, and it solves for the improvement in close rate the field would have to produce to be worth asking.
Runs in your browser. Nothing you type is sent anywhere, stored, or logged — there is no request to send it in. Built by the team behind the dishonest dashboard.
How this is calculated
Every figure above comes from the arithmetic below. No weighting, no model, no numbers of ours mixed into yours.
Completions, before and after
completions now = visitors × completion rate completions after = completions now × (1 − expected drop) lost = completions now − completions after
The drop is relative, not in percentage points. An 8% drop on a 12% completion rate gives 11.04%, not 4%.
The break-even, solved rather than assumed
revenue is unchanged when completions after × new close rate = completions now × close rate so new close rate = close rate × (completions now ÷ completions after) required lift = (completions now ÷ completions after) − 1
Average deal value cancels out of both sides, which is why the break-even lift does not depend on it. It only matters once you put a number on the improvement you expect.
Only if you enter a forecast lift
revenue now = completions now × close rate × average deal revenue after = completions after × close rate × (1 + forecast lift) × average deal
Left at zero by default, on purpose. The break-even is arithmetic. The forecast is a claim about the future, and it is yours rather than ours.
Where the defaults come from
We do not know what a form field costs in completion, and we are not going to pretend otherwise. This is the argument the category has been having since roughly 2015 with no published data on either side. Every “each extra field costs you N%” figure in circulation traces back to a small number of vendor studies on forms and audiences that are probably not yours. So the completion cost is an input here, not a constant, and the default of 8% is a placeholder we chose to be plausible rather than to be right.
The direction is not even settled. A qualifying field that loses you people who were never going to buy improves the leads you keep and looks like a failure on a completion-rate dashboard. That is the whole reason this page solves for the required lift instead of forecasting a loss.
The rest of the inputs — traffic, completion rate, close rate, average deal — are yours and are all knowable. Nothing of ours is mixed into them.
What this cannot tell you
It cannot tell you whether the field will actually improve lead quality. That is the number the whole decision turns on and the one nobody has. What it can do is tell you how big the improvement would have to be, which turns an argument into a testable claim.
It treats the lost submissions as average. They are probably not: if the field puts off people who were never going to buy, the ones you lose close worse than your baseline and the real break-even is easier than this shows. If it puts off busy senior buyers, they close better and it is harder. The direction of that error depends entirely on which field you are adding.
It also ignores where in the form the field goes, whether it is required, and whether asking it later would get you the same answer with none of the cost. Often it would.
If you want to find out which step of the form is actually losing people before adding anything to it, use the drop-off calculator.
Why we built this
Every number on this page is one your form builder could have told you and didn’t.
Endpoint Forms is an open-source form builder for marketers: forms built to convert, data that goes wherever you need it, and every submission carrying what it turned out to be worth. It is not shipped yet. The waitlist is where we tell you when it is.