Chancellor Dennis Walcott testified earlier this week before the City Council about the city's preliminary education budget.

The city’s early estimates of how much it will be spending on education next year are simultaneously too low and too high, according to an analysis released by the city’s Independent Budget Office today.

According to the IBO’s analysis, the city’s preliminary education budget overstates the total increase in Department of Education spending next year. But it also understates how much it will spend on 26 new charter schools that are set to open in September, according to the IBO, which pegs those schools’ costs at $51 million.

Overall, the report’s basic thrust is the same as in the IBO’s previous analysis of Mayor Bloomberg’s November financial plan: Spending on instruction is poised to fall as spending rises in other categories, such as pension and transportation costs.

On Tuesday, Chancellor Dennis Walcott explained to skeptical members of the City Council that the department expects a $64 million shortfall in the preliminary budget to disappear by the time the official budget is proposed in May. Between now and then, significant adjustments are likely.

Walcott also told the council that the department is committed to preventing any cuts to individual schools’ budgets, and the IBO’s report doesn’t affect that message, department officials said today.

“As the chancellor testified on Tuesday, we do not foresee reductions to school budgets or system-wide layoffs at this time,” said spokeswoman Barbara Morgan in a statement.

The city will get a hand in eliminating the projected shortfall from state funds. Today, the state released details about how much each school district will receive under the budget approved earlier this week. New York City schools will get $7.92 billion, up from $7.84 billion in Gov. Andrew Cuomo’s preliminary budget.

The IBO’s analysis suggests that the financial impact of growth in the city’s charter school sector is likely to be felt long after Bloomberg leaves office at the end of 2013.

“Combining the effects of new schools to be opened in 2012 and 2013, we estimate that the cost of charter schools will be $82 million more in 2014 than the current Financial Plan estimates,” the report says. “These additional costs will grow to $143 million by 2016, even if no new charter schools were to open after September 2013.”

The main message of the IBO’s report is that the city’s employment picture appears to be growing rosier — but that the new jobs are unlikely to come in high-paying fields that would boost the city’s tax revenue substantially. The complete IBO report is below.