Some say $1000, some say 3-6 months income, some say 3-6 months bare bones expenses, some say the deductibles of your insurance policies. Of you're on a single income, I'd err on the higher side. But with student loans definitely not too much. Whatever makes you comfortable, knowing your own circumstances of job security, availability of family help, if you have a mortgage, etc. It will also depend on how long you'll be throwing all your money at student loans (4 months? 4 years? 14 years?) - you may have higher risk tolerance if the time frame is shorter. Also consider how much excess monthly cash flow you have to cover an emergency on a month to month basis. If you're putting 2,000/mo extra toward loans, you could kind of see that like a built in 2,000 emergency fund, because if something happened (other than losing your job), you'd have 2,000 spare cash within 30 days.
We went down to 3K in our emergency fund in the last 6 months of paying off debt (our monthly expenses total 2K). It felt a little low but we had a lot of extra cash flow each month and family available to help if it came to that. We also had no mortgage. Now that we are debt free we keep it at 10K.
Basically there's no one-size-fits-all answer. Keep an amount that makes you feel comfortable and secure.
