Just plug in your address and see how much more you pay each year. The new King County tool also calculates an estimate for renters.

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Every time a tax hike lands on the ballot, voters get pummeled with numbers describing what the increase would mean.

Take Seattle Proposition No. 1, which is under consideration now. The new education levy, pegged at 36.5 cents per $1,000 of assessed value, would cost the owner of a median home about $242 next year, up from $136 this year for the city’s expiring levies. Put another way, a $106 bump. Or $9 per month. Or a latte every other week.

Now King County Assessor John Arthur Wilson is touting yet another way to check the math, using an app that he says can help homeowners and renters alike.

Wilson’s online Taxpayer Transparency Tool, applied to a Seattle measure for the first time this election, lets voters plug in their addresses to see exactly how much the education levy would tax their individual properties.

For example, Starbucks would pay $22,000 for the new levy at its massive Sodo headquarters next year, up from $14,000 this year, an increase of about $8,000.

“The intent here isn’t to take sides one way or another,” Wilson said. “You just want people to understand.”

The tool can be more personal and precise than estimates used by political campaigns, Wilson said.

“Usually, you start out with a median valued home. But who lives in a median valued home?” the assessor said. “Then you quickly get into how many lattes … and pretty soon you have a terrible caffeine buzz on.”

Renters can use the tool to get a grip on ballot measures by viewing potential per-unit tax increases for each apartment building in the city, Wilson said.

The apartment numbers are more squishy because some units are larger or nicer than others and because landlords don’t always convert tax hikes into equivalent rent increases.

Wilson believes the tool is unique to King County. It launched this year.

“We looked around the nation and we haven’t seen anything similar yet,” he said.