How to forecast software spend and build a SaaS budget
Most software budgets are built by taking last year's total and adding a bit. It is quick, and it is almost always wrong, because a software portfolio does not grow in a smooth line. It grows in steps: a renewal reprices, a team adds fifteen seats, a contract you meant to cancel rolls over for another year. A single number for the year hides all of that.
A forecast worth having answers a more specific question: what will we pay, month by month, over the next twelve months, and how much of that is already locked in? This guide shows how to build that view from data you already hold, and how to turn it into a budget you can actually manage.
Why software spend is hard to forecast
Three things make software harder to forecast than most recurring costs.
- Renewals cluster. Contracts signed in the same busy quarter tend to renew in the same busy quarter. A calm summer can be followed by an autumn where four large renewals land within six weeks of each other.
- Per-seat costs drift upward. A tool priced per user grows every time someone is added, and nobody signs off on the total. Fifty seats at 12 per month is 7,200 a year; let it drift to seventy seats and you are at 10,080 without a single new contract.
- Auto-renewals move the goalposts silently. A contract that renews automatically does not wait for your budget cycle. If you have not tracked the notice period, the decision to spend has already been made for you.
We cover the auto-renewal trap in detail in the hidden cost of auto-renewing SaaS. For forecasting, the point is simpler: you cannot budget for a portfolio whose costs change without anyone deciding to change them.
Committed spend versus discretionary spend
The single most useful split in a software budget is between committed and discretionary spend.
Committed spend is money you are contractually on the hook for. If a tool renews in March on a twelve-month term and the notice window has already closed, that year of cost is committed whether you use the tool or not. Discretionary spend is everything you could still stop: month-to-month subscriptions, tools inside their notice window, and seats you could remove at the next renewal.
The distinction matters because the two behave differently under pressure. When you need to cut, you can only move discretionary spend quickly. Committed spend has to wait for a notice window to open. Knowing which bucket each line sits in, and when a committed line becomes discretionary again, is the difference between a budget you can steer and one you can only watch.
Building a 12-month forward view
A forward view is just your renewals laid out on a calendar with the right cost attached to each. You can build it from three fields you should already be recording in your software register: the renewal date, the notice period, and the per-seat or flat cost.
- List every tool with its renewal date and term. A tool that renews on 1 November on an annual term contributes its full year of cost from that date.
- Attach the current cost. For flat plans, use the contract figure. For per-seat plans, use today's seat count times the per-seat price, not the count from when you signed.
- Mark the notice deadline for each. This is the renewal date minus the notice period, and it is the last day you can act before the cost commits.
- Spread the cost across the months. Place each renewal's cost in the month it falls, so you can see where the spend clusters rather than dividing the annual total by twelve.
Take a small example. Say you run three tools: A at 9,000 a year renewing in November, B at 6,000 a year renewing in November, and C at 500 a month, month-to-month. A flat twelfth-of-the-total view would show a smooth 1,750 a month. The real forward view shows 500 a month all year, plus a 15,000 spike in November when A and B both land. Same annual total, very different cashflow, and only one of those views lets you plan for the spike.
If some of your tools have no owner and no clear renewal date, the forward view will have holes. Closing those is a separate exercise, covered in finding software nobody owns, and it is worth doing before you trust the forecast.
Keep-versus-exit scenarios
Once you have a forward view, you can run two scenarios against it. The keep scenario assumes you renew everything at current seat counts: it is the top of your range, the number you pay if nothing changes. The exit scenario assumes you cancel everything you are able to cancel and keep only what you are committed to: it is the floor, the least you can spend without breaking a contract.
Using the example above, the keep scenario over twelve months is 21,000: A, B and a full year of C. The exit scenario, if you gave notice on C and let A and B run to the end of their committed terms, might be 15,000. The gap between the two, 6,000, is your discretionary room. That gap is the part of the budget you actually control this year.
StackTrackr's Commitments report builds both scenarios from your renewal dates and notice periods, and shows outstanding liability and forward cashflow over a horizon you choose. It is the difference between guessing at your discretionary room and reading it off a page.
Turning the forecast into a budget
A forecast describes what will happen. A budget is a decision about what you will allow to happen. To get from one to the other, set your budget somewhere between the exit floor and the keep ceiling, then decide in advance which discretionary lines you will fund and which you will let lapse.
The forecast only stays useful if you keep it current, so give it a review cadence rather than treating it as an annual event.
- Monthly: check the next ninety days of notice deadlines so no committed cost slips past a window unnoticed.
- Quarterly: refresh per-seat counts, since this is where drift hides, and compare actual spend against the budgeted range.
- At each renewal: decide keep or exit deliberately, and record the reason, so the next review starts from a decision rather than a default.
None of this requires new tooling if you are disciplined with a spreadsheet, but the discipline is the hard part: the dates have to be right, the seat counts current, and the notice windows watched. That is exactly the work StackTrackr is built to do for you. See how it tracks renewals, notice periods and costs, or read the companion guide on tracking software renewals for the process that feeds the forecast. When you are ready to build your own forward view, start with a free account.