A 5K is short enough that pacing mistakes are expensive and long enough that a plan helps. The workflow is simple: settle on a target time, convert it to a split table with the race split calculator, and check the cumulative column at each course marker.
Step 1: pick the target and get the pace
A 25:00 5K is a pace of exactly 5:00 per kilometer, about 8:03 per mile, or 12.00 km/h. Enter 5 km and 25:00 in the pace calculator, confirm the pace feels consistent with your recent runs, then carry the same numbers into the split planner. Keeping one canonical target avoids the classic mistake of re-typing a rounded pace and drifting off the original goal.
Step 2: choose intervals that match the course
Pick the interval you will actually see on the course. Road 5Ks usually mark every kilometer (and often every mile), so a 1 km table with five rows is the default. If the race marks miles only, use the 1-mile preset — the calculator then shows four rows, the last one covering the remaining 171.968 meters after the third mile marker. On a track, set the custom interval to 400 meters for a 12.5-lap table.
The 25:00 example with 1-mile intervals produces cumulatives of 8:03, 16:06, 24:08 and a finish at 25:00. The third mile looks a second faster than the others; that is display rounding of exact cumulative times, not a planned surge.
Step 3: read the table the right way
Race against the cumulative column, not the segment column. If you cross the 3 km marker at 15:10 on a 25:00 plan, you are 10 seconds up — the table gives you the fact, and you decide what to do with it. Segments are there to show what each stretch should take when the plan holds.
Step 4: print and carry it
The print layout keeps the header, your assumptions and the method note while hiding the buttons, so the sheet reads cleanly on a race band. If you want the same target distributed differently across the race — a faster second half, for example — take the same numbers to the negative split calculator and compare scenarios side by side.
A note on honest limits
The table assumes even speed over the whole distance. Real courses have turns, gradients and crowding at the start, so treat the table as the arithmetic baseline your deviations are measured against — not as a forecast of the day.