Insertion Loss Budget Calculator
Enter your loss budget and the loss of each part of the channel to see the total and how much margin is left.
Enter your loss budget and at least one loss source to see the margin.
Simple addition of the values you enter; it does not model reflections, crosstalk or frequency-dependent effects, and the budget is your own number. The 10% margin guide is a rule of thumb for this tool, not a standard. Estimates for general planning purposes — always verify against your interface specification and your connector and cable manufacturers' data.
How This Is Calculated
Insertion loss in decibels (dB) adds along a channel, so the total loss is the sum of each segment:
Total = (trace length × trace loss) + (connectors × loss per connector) + (cable length × cable loss) + other losses
Margin is your budget minus the total. The status uses a simple rule of thumb of this tool: 10% of the budget or more is shown as within budget, under 10% as tight, and below zero as over budget. The rule of thumb is not part of any standard.
Use loss values at the Nyquist frequency of your signaling rate, from your board stackup, connector and cable data. The budget itself comes from your interface specification. For how insertion loss, return loss and crosstalk fit together, see Insertion Loss vs Return Loss Explained.