Compare current race times with old PBs using age grading

Old personal bests can be inspiring. They can also be brutal.

A 10K time from your 30s may look impossible in your 50s. A marathon PB from years ago may not reflect the runner you are now. The raw clock does not know that you have aged, changed jobs, recovered from injuries or rebuilt your training from scratch.

Age grading gives you a fairer way to compare.

The problem with old PBs

Personal bests are simple: fastest ever wins.

That is useful, but it can become discouraging as you get older. A slower raw time does not always mean a weaker performance. It may mean you are producing a strong result in a different age group.

Age grading helps separate the performance from the nostalgia.

What to compare instead

Instead of comparing only raw times, compare:

• age-graded percentage
• age-adjusted equivalent time
• course and conditions
• training context
• how the result fits your current life

The age-graded number will not tell the whole story, but it gives you a better starting point.

Example: old 10K PB versus current 10K

Imagine you ran 10K much faster in your 30s than you do now.

The raw time says the old result was better. That may still be true. But age grading might show your current result is closer than you thought, or even stronger in age-adjusted terms.

That is powerful because it keeps competition alive without pretending you are the same athlete you were twenty years ago.

A concrete 10K example

Imagine a male runner who ran 45:00 for 10K at age 35, then runs 52:00 at age 55. The raw clock gives an easy answer: 45:00 is faster.

Using the current TruePace Run calculator, the 45:00 at age 35 estimates at 59.2% age graded, with an age-adjusted equivalent around 44:35. The 52:00 at age 55 estimates at 59.6%, with an age-adjusted equivalent around 44:16.

That does not erase the old PB. It does show that the current performance may be at least as strong in age-group terms. For an ageing runner, that is not a loophole. It is useful context.

This is the point that matters: age grading should not be used to rewrite your running history. The old PB still happened, and it still deserves its little place on the mental mantelpiece. The calculator simply lets you ask whether today's runner is performing at a similar level relative to age.

Try the same idea at 5K or marathon

The method works best when the distance is the same. Compare a 5K PB with a current 5K, or a marathon PB with a current marathon. Mixing distances can be interesting, but it brings in different demands: 5K rewards speed and tolerance for discomfort, while the marathon adds fuelling, durability and the slow negotiation with your own legs after 20 miles.

For example, a runner who was proud of a 25:00 5K at 40 might find that the same raw time at 60 carries a much stronger age-graded percentage. That does not mean the 60-year-old version has magically beaten the 40-year-old version. It means the result deserves to be judged with the age context included.

How to do the comparison

Use TruePace Run twice:

• Enter your old PB with your age at the time.
• Note the age-graded percentage and adjusted time.
• Enter your current result with your current age.
• Compare the age-graded numbers.
• Add human context: course, weather, training and recovery.

Do not compare one number blindly. Use it as a lens.

What to write down

A good comparison needs more than two calculator outputs. Write down the boring details too, because the boring details are usually where the truth hides.

• the official finish time and distance
• your age on race day
• the age-graded percentage
• the age-adjusted equivalent time
• course profile and weather
• whether the race was a target effort, training run or comeback marker

That turns age grading from a single flattering number into a small race note you can come back to later.

A simple PB comparison note

If you keep a training log, write the comparison in plain English rather than only saving the percentage. Something like: "Old 10K PB was faster on the clock; current 10K is similar age-graded, on a slower course, after a disrupted winter." That kind of note is much more useful than a naked number.

It also stops the calculator becoming a comfort blanket. Sometimes the old PB really was stronger. Sometimes the current result is better than your mood gives it credit for. The point is to make the comparison fair enough that you can learn from it.

Why this can be motivating

Age grading can show progress that raw time hides.

Maybe your current 5K is slower than your lifetime best, but your age-graded percentage is similar. Maybe your marathon is slower, but the performance is stronger for your age. That can make goals feel more realistic and more meaningful.

The aim is not to live in the past. It is to understand the present fairly.

When not to force the comparison

There are times when an old-PB comparison is not the right tool. A comeback race after injury, a pacing job for someone else, a deliberately conservative tune-up race or a heat-affected summer slog may tell you something useful, but not the same thing as an all-out PB attempt.

In those cases, use the calculator result as a bookmark rather than a verdict. Save it, add the context, and wait until you have a cleaner race before making big conclusions about your current level.

What age grading cannot fix

Age grading does not know everything. It cannot fully adjust for:

• hilly courses
• heat or wind
• injury comeback races
• pacing someone else
• different shoes
• years of interrupted training

So use it carefully. It is a comparison tool, not a courtroom verdict.

A fair way to use old PBs

Keep the old PB as the official record. You earned it. Then use age grading to ask a different question: how does today's performance compare with the runner you are now?

That is where the tool is most useful. It gives you permission to stay ambitious without pretending time has stood still. The practical next step is to calculate one old PB, calculate one current result, save both links and compare them with the same method.