[logn]

Completely ignore your current pay and look at market rates. Go to glassdoor.com, indeed.com, salary.com, government data, anecdotal data.

When employers look at compensation on their teams, they don't say, Ok we pay people 19% higher than their previous job so that's our target for candidates. No, they look at their average pay package and what the market is paying to budget payroll.

If the company asks about your current pay and why you're asking for such a big bump, you can say simply that you're looking to be compensated fairly at current market value. You can add fluff like you're much more skilled and ready to take on much greater responsibility. Coming from a startup I always said that I placed a high value on my options. Don't let anyone talk you down from market rate.

[eshvk]

More importantly, have friends with whom it is completely OK to talk about how much you make, this will give you a good sense for the market.

( In America, there is a stupid tradition where people think the act of telling your coworker or friend how much you make is bad, this (put on tinfoil hat) just serves the man. )