Most builders track budget vs. actual. That's one comparison. But a single comparison can't answer the two most important questions in construction finance: "How much has the plan changed from what we agreed?" and "How are we tracking against the plan we're running today?"
You need three numbers to answer both.
The Original Baseline
This is the budget as agreed before construction started. It's locked the moment the project kicks off — immutable, permanent, always visible. It represents what you committed to, what the homeowner or lender signed off on, what the contract says.
The baseline doesn't change. That's the point. When reality requires you to adjust the budget, you adjust the working budget. But the baseline remains as a reference point for every conversation about what changed and why.
The Current Budget
This is the live, working budget — the plan as it stands today. Lumber prices jumped 20%? Increase the Framing Materials line. The homeowner upgraded to custom tile? Increase Interior Finishes. A phase came in under and you want to reallocate the savings? Move it.
Every change to the current budget is logged in an immutable change log: who changed it, when, what the previous value was, what the new value is, and why (required for any single change over $1,000). The history is always one click away.
Actual Spend
This is the number most builders track but rarely trust. In most systems, Actual Spend is what someone entered in a spreadsheet or manually updated in the software. In BLT, Actual Spend is a live rollup of real transactions — every receipt the PM photographed, every labor hour logged, every subcontractor invoice recorded, every manager purchase entered. It can't be manually edited. It's the truth.
The Two Variances You Actually Need
With three numbers, you get two variance columns that answer different questions:
Budget Delta (Current − Baseline): How much has the plan shifted from what was agreed? A +$3,000 delta on Framing Lumber means you're planning to spend $3,000 more than originally budgeted for that line. This is the number you show a homeowner when explaining why the project is going to cost more than the contract price.
Spend Variance (Current Budget − Actual): How are you tracking against the current plan? A +$6,700 variance on Framing Lumber when the phase isn't complete yet means you're trending well under the current budget — useful information for projecting whether you'll hit the phase on budget.
Starting Right
BLT imports your existing budget from a spreadsheet — CSV or XLSX. The column mapper handles phase matching and amount assignment. Once imported, the baseline is locked automatically. From that point, you modify the current budget freely while the baseline stays frozen as your reference point.
If you're managing construction with a single budget number, you're making decisions without half the information you need. The third number — the baseline — is the one that keeps you honest about what changed and why.