In Excel: open Data ▸ What-If Analysis ▸ Goal Seek, set "Set cell" to the formula whose result you want to hit, type the target in "To value", and pick the single input cell Excel should adjust in "By changing cell".
Build the target formula in one cell (e.g. B10, the PMT payment) so it depends, directly or indirectly, on a single adjustable input cell (e.g. B2, the rate).
Open Data ▸ What-If Analysis ▸ Goal Seek.
Set "Set cell" to the formula cell (B10).
Enter the exact number you want in "To value" (900).
Set "By changing cell" to the input Excel should adjust (B2).
Click OK; Excel reports the found value in a confirmation dialog — click OK again to keep it, or Cancel to revert.
Need it as an auditable file?
Ships inside the linked template — formula-driven, unlocked, audit-ready.
What this does
Goal Seek is single-variable what-if analysis: it repeatedly recalculates one formula cell while nudging one input cell, iterating until the formula lands on (or very close to) the target value you specify. It works backwards from a known desired outcome to the unknown input that produces it, which is the opposite of normal spreadsheet work where you plug in inputs and read off a result. It changes exactly one input cell — for several unknowns at once, or for constraints like "keep this cell under 10", use Solver instead, which Goal Seek is not a substitute for. Keep the inputs visible and clearly labelled and the whole thing stays auditable — anyone who opens the file later, including you, can see at a glance exactly what feeds the result and change one assumption without hunting through the formula. The difference between a quick fix and a sheet you can trust is the extra minute you spend validating “where to find goal seek in excel”. Start on a copy or a tiny sample, keep the affected cells visible, and compare the result with the tool above before you touch the real workbook. When this is a ribbon command, the selection matters more than the button: confirm the range, apply the command, then spot-check the output before saving. The point is a calculation you can defend to a CFO or an auditor, but the practical win is that someone else can open the file and understand what happened without asking you.
A worked example
A $200,000, 30-year loan sits in B1 (principal), B2 (annual rate, guessed at 6%) and B3 (term in years), with the monthly payment in B10 as =PMT(B2/12,B3*12,-B1), which currently returns $1,199.10. To find the rate that brings the payment down to exactly $900/month: open Goal Seek, set "Set cell" to B10, "To value" to 900, and "By changing cell" to B2. Excel iterates and rewrites B2 to 3.517%, at which point B10 recalculates to exactly $900.00. Reach for Goal Seek whenever you know the outcome you want — a target loan payment, a break-even price, a required exam average — but not the input that produces it. Instead of guessing values by hand and recalculating, let Excel iterate to the answer in seconds. One habit worth forming early: name the cells that hold your inputs, so the formula reads in plain language instead of a string of cell addresses. A reviewer — or you in three months — can then follow the logic without decoding what B7 and D2 were supposed to mean, which is most of what makes a sheet maintainable.
In Google Sheets
Everything above works in Google Sheets too. Excel and Sheets share the formula syntax used here; only the surrounding menus are arranged differently. That portability is deliberate — learn it once and it follows you between the two tools and across Windows and Mac. The aim was to get you unstuck fast and leave you a little more capable than a copy-paste would. The answer is at the top, the tool proves it, and the detail above shows why it holds — so the next time a colleague asks, you can answer without reaching for search. Treat “where to find goal seek in excel” as a small building block rather than a chore. Once the inputs sit in their own cells and the formula reads from them, the same setup answers a dozen related questions with a tweak, and Excel keeps every dependent figure current as the data changes. The tool above is there so you can rehearse and verify before committing anything to a real workbook; the steps and worked example are there so the logic sticks. Get it right once and it stops costing you time — it starts saving it, every time the question comes back around.
Common mistakes
- Pointing "Set cell" at a cell that has no formula dependency on "By changing cell" — Goal Seek has nothing to iterate and returns an error or no movement.
- Choosing a "By changing cell" that itself holds a formula rather than a raw input — Goal Seek needs a hard, editable value to adjust.
- Expecting Goal Seek to solve for more than one unknown at once — it changes exactly one cell; multiple simultaneous unknowns need Solver.
- Setting an unreachable target (e.g. a payment lower than the principal-only floor), which leaves Goal Seek stuck at its iteration limit without a real solution.
- Clicking Cancel on the results dialog and then being confused why the input cell looks unchanged — Cancel deliberately reverts it to the original value.
Frequently asked questions
What is the difference between Goal Seek and Solver?
Goal Seek adjusts exactly one input cell to hit one target value. Solver adjusts multiple cells at once and can add constraints while maximizing or minimizing an objective — reach for Solver once you have more than one unknown.
Why does Goal Seek say it cannot find a solution?
Usually because "Set cell" is not actually calculated from "By changing cell" through a formula chain, or because the target value is mathematically unreachable given the formula.
Does Goal Seek permanently change my input cell?
Yes — once you accept the result, it overwrites "By changing cell" with the solved value. Keep a copy of your original assumptions in another cell first if you need to compare before/after.