In this chart let's pretend you keep your payment the EXACT SAME.

If you put both loans at the same starting line (original purchase price and loan amount) then this is how it looks.

$350,000 on 8% rate = 360 months

$350,000 on 7% rate (with the same payment as the 8%) = 273 months

You save 7+ years

Here's the full chart:

FromToTime Saved
8%7%87 months
7.875%6.875%86 months
7.75%6.75%85 months
7.625%6.625%84 months
7.5%6.5%84 months
7.375%6.375%83 months
7.25%6.25%82 months
7.125%6.125%81 months
7%6%80 months
6.875%5.875%79 months
6.75%5.75%79 months
6.625%5.625%78 months
6.5%5.5%77 months
6.375%5.375%76 months
6.25%5.25%76 months
6.125%5.125%75 months
6%5%74 months
5.875%4.875%73 months
5.75%4.75%72 months
5.625%4.625%72 months
5.5%4.5%71 months
5.375%4.375%70 months
5.25%4.25%69 months
5.125%4.125%69 months
5%4%68 months
4.875%3.875%67 months
4.75%3.75%67 months
4.625%3.625%66 months
4.5%3.5%65 months
4.375%3.375%65 months
4.25%3.25%64 months
4.125%3.125%63 months
4%3%62 months
3.875%2.875%62 months
3.75%2.75%61 months
3.625%2.625%61 months
3.5%2.5%60 months
3.375%2.375%59 months
3.25%2.25%59 months
3.125%2.125%58 months
3%2%57 months
2.875%1.875%57 months
2.75%1.75%56 months
2.625%1.625%56 months
2.5%1.5%55 months
2.375%1.375%54 months
2.25%1.25%54 months
2.125%1.125%53 months
2%1%53 months
1.875%0.875%52 months
1.75%0.75%52 months
1.625%0.625%51 months
1.5%0.5%51 months
1.375%0.375%50 months
1.25%0.25%50 months
1.125%0.125%49 months

These numbers change if you're further along in your mortgage.

It's more of an illustration at how much TIME 1% difference can make