Baseline vs Actual Gantt Chart
See exactly where a project is drifting from plan. This Gantt view overlays actual progress on the original baseline schedule, so slippage, and how much, is visible task by task before it compounds into a missed deadline.
Create Baseline Gantt →What is a Baseline vs Actual Gantt Chart?
A baseline vs actual Gantt chart adds a critical dimension to the standard Gantt: it preserves the original planned schedule, the baseline, and displays actual start and finish dates alongside it. This lets you see not just where tasks stand, but how far they have drifted from what was planned.
The baseline is captured once the plan is approved and then frozen. As the project runs, actual progress is recorded against it, and the visual gap between the baseline bar and the actual bar for each task is the schedule variance, immediate evidence of whether a task started late, ran long, or finished early.
This comparison is what turns a Gantt chart from a static plan into a control tool. Without a preserved baseline, a schedule that is continually updated loses all memory of the original commitment, and slippage becomes invisible. The baseline vs actual view keeps the original promise in sight so drift can be caught and addressed early.
In plain terms: A normal Gantt shows the current plan. This one also keeps the original plan frozen underneath, so you can see the gap between what you promised and what's actually happening. That gap, task by task, is your early warning that the project is slipping, while there's still time to react.
Key Features
Frozen Baseline
The approved schedule is captured and frozen, preserving the original commitment as a fixed reference.
Actual Overlay
Actual start and finish dates are shown alongside each baseline bar, making the variance visible at a glance.
Schedule Variance
The gap between baseline and actual is the slippage, task by task, revealing where and how much the project has drifted.
Key Formulas
Using the Comparison
Watch the trend, not just single tasks. Isolated slippage on a task with slack may not matter, but consistent drift, or slippage on tasks that others depend on, signals the whole schedule is at risk and needs intervention.
The baseline should be changed only through deliberate re-baselining, not casually adjusted to match reality. Moving the baseline to hide slippage defeats the tool's purpose; the value lies precisely in preserving the original commitment as an honest reference.
Assumptions & Validation
Baseline Captured
A baseline was frozen when the plan was approved.
If violated: Establish and freeze a baseline before tracking begins.
Accurate Actuals
Actual dates are recorded honestly and promptly.
If violated: Update actuals regularly; stale data hides slippage.
Controlled Re-baselining
The baseline changes only through deliberate re-baselining.
If violated: Do not quietly move the baseline to mask drift.
⚠️ Check assumptions first
The whole value of this view depends on a baseline that is frozen and honestly maintained. Casually shifting the baseline to match reality, or failing to record actuals promptly, hides the very slippage the tool exists to reveal. Freeze the baseline when the plan is approved, record actuals as work happens, and re-baseline only through a deliberate, agreed decision, not to make the chart look better.
When NOT to Use Baseline vs Actual Gantt Chart
Initial Planning
For laying out the schedule before work starts, a basic Gantt chart is what you need first.
Critical-Path Analysis
To find which tasks control the finish date, use PERT/CPM.
Milestone Tracking
To focus on key dates and phase gates rather than task-level variance, use a milestone chart.
Industry Applications
Schedule Control
Track how actual progress compares to the plan and catch slippage early.
Status Reporting
Show stakeholders exactly where the project stands against its original commitment.
Variance Analysis
Quantify schedule variance task by task to focus corrective action.
Project Reviews
Provide an honest baseline-versus-actual picture at gate and review meetings.
Frequently Asked Questions
What is a baseline in a Gantt chart?
A baseline is the original approved schedule, captured and frozen at the start of a project as a fixed reference. As the project progresses, actual dates are recorded against it. The baseline preserves the original commitment so that slippage can be measured; without it, a continually updated schedule loses all memory of what was originally planned, and drift becomes invisible.
What is schedule variance?
Schedule variance is the difference between a task's actual dates and its baseline dates, that is, how far it has drifted from plan. A task that started or finished later than its baseline has negative schedule performance, while one ahead of baseline is early. Displayed task by task on a baseline vs actual Gantt chart, schedule variance shows precisely where and how much a project is slipping.
Why shouldn't I just update the schedule instead of keeping a baseline?
Continually updating the schedule without a preserved baseline erases the original commitment, so there is nothing to measure slippage against. The whole point of a baseline is to keep the original plan visible as an honest reference. Moving or overwriting it to match reality hides the drift the tool is meant to reveal, which is why the baseline is frozen and changed only through deliberate re-baselining.
When should I re-baseline a project?
Re-baselining should be a deliberate, agreed decision, typically after a significant approved change in scope, resources or timeline that makes the original baseline no longer a meaningful reference. It should never be done casually to mask accumulated slippage. Re-baselining resets the commitment against which future progress is measured, so it is reserved for genuine, sanctioned changes to the plan.
How is this different from a basic Gantt chart?
A basic Gantt chart shows the current schedule as bars on a timeline. A baseline vs actual Gantt chart adds the frozen original plan and overlays actual progress on it, making the variance between planned and actual visible. The basic chart is a planning view, while the baseline vs actual chart is a control view used to track and manage a project against its original commitment.
How does this help catch problems early?
By showing the gap between baseline and actual for every task, the chart reveals slippage as it happens rather than only when a deadline is missed. Consistent drift, or slippage on tasks that others depend on, signals risk to the overall schedule while there is still time to intervene. This early visibility is what makes the baseline vs actual view a control tool rather than just a record.
Catch Schedule Slippage Early
Compare actual progress against a frozen baseline task by task. Free during Beta.
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