Former vice president Joe Biden has reached the number of delegates needed to clinch the Democratic Party’s presidential nomination, according to Edison Media Research.

Democrats divide their 3,979 pledged delegates among the states, the District of Columbia, territories and other jurisdictions without electoral votes. That is based on a formula that takes into account both population and the Democratic Party’s strength in particular jurisdictions. (While Massachusetts and Tennessee have similar populations and 11 votes each in the electoral college, more people vote for Democrats in the former than the latter, so Massachusetts has 91 pledged delegates and Tennessee has 64.)

Those delegates are then pledged to candidates on the basis of results in primaries and caucuses.

With Sen. Bernie Sanders’s departure from the race April 8, Biden became the party’s presumptive nominee, though he has not yet won the 1,991 unpledged delegates needed. While Sanders is no longer running, he’s working to get 25 percent of the party’s delegates so that he can affect the party’s platform at the convention. Biden and Sanders struck a deal allowing Sanders to keep statewide delegates he would have lost as a consequence of dropping out.