Pit Strategy Tool

Race

Look up the number of laps for the race and enter it here.
Number of laps:
Go to the track and test how much time is lost during a typical pit stop. Enter the time here.
Pit stop time loss:	.

Soft tyres

Drive one (or more) stints on soft tyres. Note the typical lap time at the beginning of the stint, on fresh tyres. Note the typical lap time at the end of the stint, with worn-down tyres. Also note the number of laps in the stint. Enter the times and lap count here (if you want to ignore tyre wear, just enter the same time in both fields).
Lap time at beginnig of reference stint:	.
Lap time at end of reference stint:	.
Laps in reference stint:
Decide how many laps you want to drive in a stint with soft tyres during the race. Consider how comfortable you are with these tyres and their wear, as well as how long you can drive with a full tank.
Laps in race stint:

Medium tyres

Drive one (or more) stints on medium tyres. Note the typical lap time at the beginning of the stint, on fresh tyres. Note the typical lap time at the end of the stint, with worn-down tyres. Also note the number of laps in the stint. Enter the times and lap count here (if you want to ignore tyre wear, just enter the same time in both fields).
Lap time at beginnig of reference stint:	.
Lap time at end of reference stint:	.
Laps in reference stint:
Decide how many laps you want to drive in a stint with medium tyres during the race. Consider how comfortable you are with these tyres and their wear, as well as how long you can drive with a full tank.
Laps in race stint:

Hard tyres

Drive one (or more) stints on hard tyres. Note the typical lap time at the beginning of the stint, on fresh tyres. Note the typical lap time at the end of the stint, with worn-down tyres. Also note the number of laps in the stint. Enter the times and lap count here (if you want to ignore tyre wear, just enter the same time in both fields).
Lap time at beginnig of reference stint:	.
Lap time at end of reference stint:	.
Laps in reference stint:
Decide how many laps you want to drive in a stint with hard tyres during the race. Consider how comfortable you are with these tyres and their wear, as well as how long you can drive with a full tank.
Laps in race stint:

Soft stint

Medium stint

Hard stint

These are the calculated lap times for stints on each type of tyre.

Strategies

Here you can review a couple of pit strategies and get a suggestion for the race.

The order of the stints has no influence on the calculated race time. SOFT->MEDIUM->HARD could also be MEDIUM->HARD->SOFT or any other order as long as the number of laps for each tyre remains the same.

Assumptions:

Softer tyres are always preferred.
Lap times increase linearly with tyre wear.
Weight changes (from fuel consumption) are not explicitly considered. They may have influenced your reference laps, though.
Tyres temperatures are not explicitly considered. They may have influenced your reference laps, though.

Pit strategy tool (beta)