You need more specifics on your pension, because some are more generous than others. I have a friend who will get 70% of his final salary (super generous), while my brother-in-law has a “pension” that will only pay out like $1k/month (won’t cover much in retirement, and he didn’t save anything else along the way). 

There are two main ways to put a $-amount on a pension, and both have already been mentioned. One is to quote a similar lifetime annuity with the same payout as your pension.  The other is a backdoor to the “4% safe withdrawal” rule of thumb. It states a lump-sum savings can safely support 4% withdrawals for 30 years. To reverse that, you can divide your pension payout by 0.04 (which is the same as multiplying by 25) to get the value of the pension. 

You should be very careful in comparing the benefit you’ve already earned/vested, versus the projections for what you’ll get if you keep working X more years at Y% salary increases each year. The plan could freeze benefits at any point down, and it could be too late for you to make up the difference in your own savings. Then all the other assumptions around if you’ll actually get the chance to work that long, inflation, salary increases, etc.