For future homebuyers wondering when to stop saving and get into the housing market, the math is clear: the sooner the better. With home values forecasted to rise in every major U.S. metropolitan area over the next year, a 20 percent down payment on the median-priced home today will cost thousands of dollars more just one year from now, according to a new report from Zillow.

Nationally, the median home will be worth $6,275 more a year from now, according to Zillow’s home value forecasts. That means the average U.S. buyer will need to save an additional $105 a month – $1,260 total over the next year – just to account for how much more a 20 percent down payment will cost a year from now.

In Greater Boston, the median home will be worth $12,347 more a year from now, according to Zillow’s home value forecasts. The average buyer will need to save an additional $206 a month – $2,469 total over the next year. That’s twice the national average.

Saving for a down payment is one of the biggest hurdles to homeownership. That may be why more than half (59 percent) of all first-time buyers today put less than 20 percent down on their home purchase, according to Zillow Group’s Consumer Housing Trends Report 2017. However, a small down payment does not come without risks. The report also found that buyers with larger down payments are more likely to get their offer accepted, averaging just 1.9 total offers before winning their house compared to 2.4 for buyers with lower down payments. When time is money, a low down payment can be costly.

“Sky-high rents and rising home prices are putting first-time buyers in a bit of a catch-22,” Dr. Svenja Gudell, Zillow chief economist, said in a statement. “Buying now with a low down payment can be riskier, and the offer may not be considered as competitive by the seller. However, a renter who saves for another year to reach a larger down payment may find that the home they love today is outside their budget a year from now. For those considering buying in the next year, getting into the market today may make more financial sense than they think.”