Montana Trainer wrote:
I'd like to do some laddering with CD's, and wonder
if there's a template out there that is set up to
show the return I'd get with different rates and for
3, 6 and 12 month periods.

If the bankrate.com calculator is something like what you
are interested in, the following "template" might work for
you.

A1, A2, etc = CD investment for each rung
B1, B2, etc = the maturity period of each rung, in months
C1, C2, etc = annual interest rate for each rung
D1, D2, etc = FV($C$10/2,($B$10-B1)/6,,-FV(C1/2,B1/6,,-A1))

where $C$10 is the interest rate for the last rung, and
$B$10 is the maturity period of the last rung.

For example, the following mimics the result of a 5-rung
ladder with 1-year maturity periods computed by the
bankrate.com calculator.

A B C D
1 $5000 12 4.40% $6,298.74
2 $5000 24 4.45% $6,283.98
3 $5000 36 4.45% $6,266.19
4 $5000 48 4.45% $6,248.45
5 $80000 60 4.74% $101,115.33
6 $100000 $126,213.00 (sum)

Notes:
1. bankrate.com uses uneven CD investments to ensure
that $5000 is available every 1 year while maximizing
your return, assuming that the last rung offers the
highest interest rate. Alternatively, if dollar cost
averaging is your goal, you might use equal amounts --
$20,000 in this case.

2. bankrate.com compounds every 6 months. Most CDs
compound daily. In the FV() function, you might
replace "/2" and "/6" with "/360" and "*30" respectively.

3. The FV() function assumes that when each CD matures, its
appreciated value is reinvested in a CD with the maturity
and current interest rate of the last rung, since the
future interest is unknown.