Rank emergency fund homes by availability first, then see what savings-account tax, sweep-in FD tax, and your own liquid-fund assumption do to the carry.
Why does this page rank by availability instead of by after-tax return?
Because an emergency fund fails the day the money is late, not the day the return is lower. A page that sorts these from highest carry to lowest would quietly recommend the wrong product. Return matters here only as the price you pay for faster access.
Why is a plain FD below a sweep-in FD if the tax and rate can be the same?
Because the missing feature is not the rate. It is the break-glass access. A sweep-in FD is there to break automatically when the account runs short. A plain FD is there to sit untouched until you intervene, often with a penalty. Same rate, different job.
Why does the senior citizen setting change the result so much?
Because section 80TTB is both larger and wider than section 80TTA. A taxpayer under 60 in the old regime gets at most ₹10,000 on savings interest only. A resident senior citizen gets up to ₹50,000 across savings and deposits. On the same fund size, that changes the after-tax carry by real money.
Why does the liquid-fund row ask me for an after-tax return?
Because this site does not yet compute debt-fund tax lot by lot, and a made-up answer would look precise while being wrong. If you know the post-tax carry you expect, enter it. If not, use the row qualitatively: it usually sits between a savings account and a long lock-in FD on both access and return.
Should I hold all six months in savings for safety?
Usually no. Keeping the whole fund instant is safe but expensive in carry, and the cost compounds every year. The site guidance here is to keep about one month instant, the next two months same day through a sweep-in FD, and only the rest next working day, because that preserves speed where it matters most and yield where it does not.
What if I cannot get a sweep-in FD from my bank?
Then the trade becomes starker: plain savings for same-afternoon money, or a liquid or overnight fund for next-working-day money. This page still helps, because it prices the carry you give up by refusing the slower home, which is the real cost of not having the feature.