The force's latest finance report forecasts an overspend of £5.1m, up from £3.1m at the end of the first quarter of the year.
It says the main cause is a £3.3m pressure on utilities costs on top of a £300,000 pressure on fuel costs, "as well as a number of demand and inflationary pressures".
Finance chiefs at the force say they are looking at ways to cut costs in order to balance the budget.
The report was presented to the Police and Crime Commissioner's strategic board by the force's chief finance officer Mark Kenyon.
It says: "The medium-term financial plan indicates that there will be a significant budget pressure next year.
"The majority of the forecast overspend is due to the additional cost for gas and electricity in police buildings and to a lesser extent on the current high cost of vehicle fuel."
It adds that the use of temporary staff to fill "essential posts or respond to increased demand" have resulted in a forecast overspend of £500,000, prompting a review of all temporary staff posts.
It also notes a forecast overspend on supplies and services is £1.47m.
West Midlands PCC Simon Foster, said: "Significant rises in inflation are putting major pressures on the force’s budget. This has mainly been driven by rises in energy and fuel bills.
"The plain fact of the matter is that the Government’s Police Grant Settlement does not maintain the baseline funding that the force needs to operate on a day to day basis, to deliver an effective and efficient police service.
"It is clear that West Midlands Police needs a fair funding settlement. In the absence of that, I will do everything I can to protect services, but the current financial challenges will lead to very difficult choices unless the government steps in with essential financial support, to help public services facing crippling rises in costs."
The report shows the annual budget for the PCC's office is forecast to remain at almost £3m.