Zero-Based Budgeting
A budgeting method where every expense must be justified from scratch each period — starting from zero rather than adjusting last period's budget.
What is Zero-Based Budgeting?
Zero-based budgeting (ZBB) requires every expense to be justified anew for each budgeting period. Instead of starting with last month's budget and making adjustments, you start from zero and build up, asking: "Do we still need this? Is this the right amount?"
This approach forces a rigorous examination of every expense. That $500/month analytics tool you signed up for a year ago — is it still providing value? The contractor you hired for a one-time project who's still on the books — should they be?
ZBB is more time-intensive than traditional budgeting, but it's particularly valuable for startups because it prevents expense creep — the gradual accumulation of costs that individually seem small but collectively erode runway.
Why it matters
Startups are especially vulnerable to expense creep because the culture often values speed over financial discipline. Tools get added and never removed. Subscriptions auto-renew without review. Contractors become de facto employees.
Zero-based budgeting forces a regular reset. Even doing it quarterly (instead of monthly) can reveal thousands of dollars in unnecessary spending that's been quietly eating runway.
Example
Your SaaS tool budget last quarter was $8,500/month. Using ZBB, you review every tool: CRM ($200/month, essential), analytics ($500/month, used weekly — keep), project management ($150/month, team switched to a free tool — cancel), design tool ($300/month, only used by one person who left — cancel). New tool budget: $7,550/month. You saved $950/month ($11,400/year) from a 15-minute review.
How RunwayCal helps
RunwayCal's budget module supports zero-based budgeting by letting you set budget targets from scratch each period. The variance analysis then shows whether actual spending aligns with your fresh budget — catching expenses you intended to cut but didn't.
Common mistakes
- 1Applying ZBB to every category every month (it's exhausting — do it quarterly or for the biggest expense categories)
- 2Not having the organizational authority to actually cut expenses that ZBB flags
- 3Treating ZBB as a cost-cutting exercise only, instead of a resource allocation exercise
Challenge every expense — keep only what matters
RunwayCal's budget module lets you build budgets from scratch and track whether actual spending matches your fresh targets.
Set up budgeting → Start free