The headroom figure is the anticipated billing balance based on the calculation below and shows how close you are to meeting the estimated figure provided to the client.
The headroom figure is exclusive of GST. Headroom = estimated fee (as defined on the matter), less the WIP balance (time and value), less any fees already billed on the matter.
The expenses/disbursements estimate on the matter is not included in the headroom calculation. In the example below, the estimate is $2,000.00, the WIP balance is $400.00 and fees billed $120 (billed WIP excluding GST content of bill plus disbursements), so the headroom balance is $1,480.00.