Yet another study is out showing New York City charters outperforming the regular public schools — even as Mayor de Blasio keeps on working to stifle charters’ growth.

The study, by Stanford University’s Center for Research on Education Outcomes, used test scores to compare the gains of 75,000 third- through eighth-graders in 197 city charters to those of their traditional-school peers between 2011-12 and 2015-16.

It found an average charter kid displays growth in reading “equivalent” to 23 extra school days; for math, it’s 63 extra days. Every. Single. Year.

Some results were positively stunning: Kids at KIPP NYC, for example, “grew” academically by 80 more days in reading, and 137 in math. At a Success Academy in Harlem, it was 137 more days in reading, 239 in math.

Notably, the study found the gains particularly “strong” among poor black and Hispanic charter vs. regular-school kids.

Nor can critics claim that charter kids just come from more privileged backgrounds: The researchers controlled for variables like poverty, race, special-ed status and English proficiency.

These dramatic findings merely confirm what other studies have found: The city’s charters routinely outperform the traditional schools run by the bureaucrats and unions.

Trouble is, from Day 1 de Blasio has fought to slow the growth of charters, which threaten the established special interests that control the regular schools — and prosper even as those schools fail.

In particular, the mayor’s minions are dragging their feet on responding to charters’ requests for new space next fall. The city missed a Sept. 8 deadline to release documents so the Panel for Education Policy can OK charter space at its October meeting. It now has until Oct. 13 to come up with the material for the November meeting.

If the stall continues, hundreds of kids moving up to middle school and so on could be forced into failed district schools — and out of schools that are working miracles. Hundreds more would be denied the chance to start out at a charter.

If he denies such opportunity, de Blasio has no conscience at all.