After-Tax Savings Yield Calculator
The highest advertised rate is often not the one that pays you most. This compares what you actually keep after federal and state tax. Free, and nothing is stored.
Accounts you're comparing - edit the rates to match real offers
| Account | Interest | Tax | Net / year | After-tax |
|---|---|---|---|---|
| Treasury billBestNo state tax | $1,000 | −$220 | $780 | 3.12% |
| High-yield savings | $1,038 | −$366 | $671 | 2.69% |
| 12-month CD | $1,025 | −$362 | $663 | 2.65% |
In California at a 22% federal bracket, Treasury bill nets you $109 more per year than High-yield savings- even though it isn't the highest headline rate in every case.
Because Treasury bill is exempt from state tax, a fully taxable account would need to advertise 4.61% to actually match its 4.00%.
Estimates only. Uses your top marginal rate applied to all interest, which slightly overstates tax for income spanning brackets. State figures are top marginal rates and change over time. Treasury and I bond interest is exempt from state and local income tax but remains federally taxable. Not tax advice - confirm with a tax professional for your situation.
Why the headline rate misleads
Interest from bank products - savings accounts, money market accounts, and CDs - is taxable at both the federal and state level. Interest from Treasury bills and Series I savings bonds is taxable federally but exempt from state and local income tax.
That exemption is worth real money in a state with income tax, and it is missing from almost every savings comparison online. In California, a Treasury bill paying 4.00% beats a savings account paying 4.15%, because the savings account loses another 13.3% of its interest to the state. Move the same two accounts to Texas and the savings account wins. The right answer genuinely depends on where you live, which is why a single national "best rate" list cannot answer it for you.
How to use this
- Enter the amount you are deciding about, your federal bracket, and your state.
- Replace the default rates with the actual offers you are weighing.
- Compare the net per year column, not the headline APY.
Before you optimise yield
Two things matter more than the difference between these options. If you carry credit card debt near 22% APR, paying it down beats every rate here with certainty - see our payoff guide. And your emergency fund belongs somewhere liquid regardless of yield, because a CD or I bond you cannot access during an emergency is not an emergency fund.
For the full framework on matching money to the right account by time horizon, see where to keep your cash in 2026.