Boston Marathon logo
BOSTON MARATHON 2023

Amber Kosty

Bib: 19017•F

KS

0:00
0:00
/ mi
Be the first to cheer!
Overall
#0 / 26622
Top 47%
Gender (Female)
#0 / 11423
Top 31%
Division (F18-39)
#0 / 4884
Top 49%
Race Day Weather
49°/39°F
light intensity drizzle

⏱️ Race Timeline

Start
0:00:00
Race begins
5K· 3.11 mi
25:45
Rank: #16058
Start → 5K
8:17/mi
25:45 split
10K· 6.21 mi
50:50
Rank: #15687 (+371)
5K → 10K
8:04/mi
25:05 split
15K· 9.32 mi
1:15:53
Rank: #15430 (+257)
10K → 15K
8:04/mi
25:03 split
20K· 12.43 mi
1:40:48
Rank: #14951 (+479)
15K → 20K
8:01/mi
24:55 split
Half· 13.11 mi
1:46:20
Rank: #14953 (-2)
20K → Half
8:07/mi
5:32 split
25K· 15.53 mi
2:05:47
Rank: #14631 (+322)
Half → 25K
8:01/mi
19:27 split
30K· 18.64 mi
2:31:05
Rank: #14141 (+490)
25K → 30K
8:09/mi
25:18 split
20M
2:42:06
Rank: #13872 (+269)
30K → 20M
8:06/mi
11:01 split
21M
2:50:31
Rank: #13608 (+264)
20M → 21M
8:25/mi
8:25 split
35K· 21.75 mi
2:56:34
Rank: #13555 (+53)
21M → 35K
8:05/mi
6:03 split
23M
3:06:40
Rank: #13326 (+229)
35K → 23M
8:04/mi
10:06 split
24M
3:14:19
Rank: #13091 (+235)
23M → 24M
7:39/mi
7:39 split
40K· 24.85 mi
3:20:57
Rank: #12908 (+183)
24M → 40K
7:45/mi
6:38 split
25.2M
3:23:48
Rank: #12839 (+69)
40K → 25.2M
8:16/mi
2:51 split
Finish· 26.22 mi
3:31:22
Rank: #12639 (+200)
25.2M → Finish
7:26/mi
7:34 split

The Course

Is this your race?

Claim it — unlock a deeper AI report on this race, free

A personalized Race Performance Report that goes beyond this page — emailed to you, built from your real splits.

Half Splits

1st Half· via Half
Distance13.11 mi
Time1:46:20
Pace8:07 /mi
2nd Half✓ Faster
Distance13.11 mi
Time1:45:02
Pace8:01 /mi
📊Negative Split: 1.2% faster second half

Checkpoint Splits

CheckpointDistanceTime of DayTimeAvg PaceSegment TimeSegment PaceDiff
5K
3.11 mi11:17:1425:458:1725:45
8:17
-
10K
6.21 mi11:42:1950:508:1125:05
8:04
-0:13
15K
9.32 mi12:07:221:15:538:0825:03
8:04
0:00
20K
12.43 mi12:32:171:40:488:0724:55
8:01
-0:03
Half
13.11 mi12:37:491:46:208:075:32
8:07
+0:06
25K
15.53 mi12:57:162:05:478:0619:27
8:01
-0:06
30K
18.64 mi13:22:342:31:058:0625:18
8:09
+0:08
20M
20.00 mi13:33:352:42:068:0611:01
8:06
-0:03
21M
21.00 mi13:42:002:50:318:078:25
8:25
+0:19
35K
21.75 mi13:48:032:56:348:076:03
8:05
-0:20
23M
23.00 mi13:58:093:06:408:0710:06
8:04
-0:01
24M
24.00 mi14:05:483:14:198:067:39
7:39
-0:25
40K
24.85 mi14:12:263:20:578:056:38
7:45
+0:06
25.2M
25.20 mi14:15:173:23:488:052:51
8:16
+0:31
Finish
26.22 mi14:22:513:31:228:047:34
7:26
-0:50

Checkpoints & Pacing

📈Pace Line

Pace Progression

Track your pace changes throughout the race. Dot colors mark your quickest to easiest segments, relative to your own pace.

Fastest Pace

7:26 /mi

Average Pace

8:04 /mi

Slowest Pace

8:25 /mi

Loading chart...
Fastest
Middle
Slowest
Average

📊Segments

Segment Time Comparison

Time at Faster Pace

2:54:21

82% of race

Time at Steady Pace

37:01

18% of race

Time at Slower Pace

0:00

0% of race

Average Pace: 8:04 /mi

Loading chart...
Faster pace (< avg)
Steady pace (≈ avg)
Slower pace (> avg)

🎨Heatmap

Pace Heatmap

Where you sped up and eased off relative to your own pace across the race. Colors are relative to your own range, not to other runners.

Loading...
0mi6.6mi13.1mi19.7mi26.2mi
Pace:
Faster
Steady
Slower

Click or hover over segments to see details

✨Sparklines

Checkpoint Splits with Pace Trends

Overall Pace Trend

CheckpointDistanceTime of DayTimeAvg PaceSegmentPaceTrendRank
5K
3.11 mi11:17:1425:458:1725:45
8:17
#16058
10K
6.21 mi11:42:1950:508:1125:05
8:04
#15687
15K
9.32 mi12:07:221:15:538:0825:03
8:04
#15430
20K
12.43 mi12:32:171:40:488:0724:55
8:01
#14951
Half
13.11 mi12:37:491:46:208:075:32
8:07
#14953
25K
15.53 mi12:57:162:05:478:0619:27
8:01
#14631
30K
18.64 mi13:22:342:31:058:0625:18
8:09
#14141
20M
20.00 mi13:33:352:42:068:0611:01
8:06
#13872
21M
21.00 mi13:42:002:50:318:078:25
8:25
#13608
35K
21.75 mi13:48:032:56:348:076:03
8:05
#13555
23M
23.00 mi13:58:093:06:408:0710:06
8:04
#13326
24M
24.00 mi14:05:483:14:198:067:39
7:39
#13091
40K
24.85 mi14:12:263:20:578:056:38
7:45
#12908
25.2M
25.20 mi14:15:173:23:488:052:51
8:16
#12839
Finish
26.22 mi14:22:513:31:228:047:34
7:26
#12639
Faster pace
Steady pace
Slower pace

Checkpoint and Segment Rankings

CheckpointDistanceSeg. DistOverallFemalesF18-39Seg. OverallSeg. FemalesSeg. F18-39
5K3.11 mi3.11 mi160585318531814907(Top 56%)4620(Top 40%)4620(Top 95%)
10K6.21 mi3.10 mi15687+3715084+2345084+23415328(Top 58%)4866(Top 43%)4866(Top 100%)
15K9.32 mi3.11 mi15430+2574930+1544930+15414907(Top 56%)4620(Top 40%)4620(Top 95%)
20K12.43 mi3.11 mi14951+4794652+2784652+27813614(Top 51%)3884(Top 34%)3884(Top 80%)
Half13.11 mi0.68 mi14953-24657-54657-515205(Top 57%)4790(Top 42%)4790(Top 98%)
25K15.53 mi2.42 mi14631+3224484+1734484+17312932(Top 49%)3589(Top 31%)3589(Top 73%)
30K18.64 mi3.11 mi14141+4904227+2574227+25711960(Top 45%)3166(Top 28%)3166(Top 65%)
20M20.00 mi1.36 mi13872+2694083+1444083+14411105(Top 42%)2794(Top 24%)2794(Top 57%)
21M21.00 mi1.00 mi13608+2643938+1453938+14510007(Top 38%)2399(Top 21%)2399(Top 49%)
35K21.75 mi0.75 mi13555+533918+203918+2012735(Top 48%)3842(Top 34%)3842(Top 79%)
23M23.00 mi1.25 mi13326+2293811+1073811+10710267(Top 39%)2638(Top 23%)2638(Top 54%)
24M24.00 mi1.00 mi13091+2353701+1103701+1108804(Top 33%)2016(Top 18%)2016(Top 41%)
40K24.85 mi0.85 mi12908+1833619+823619+828437(Top 32%)1927(Top 17%)1927(Top 39%)
25.2M25.20 mi0.35 mi12839+693580+393580+398216(Top 31%)1943(Top 17%)1943(Top 40%)
Finish26.22 mi1.02 mi12639+2003485+953485+958019(Top 30%)1849(Top 16%)1849(Top 38%)

Segment Performance Analysis

10K→15K

0.0 - 3.1 mi

Top 56%
×21stories
+97ft-345ft

Overall

14907

Females

4620

F18-39

4620

5K→10K

3.1 - 6.2 mi

Top 58%
×5stories
+79ft-138ft

Overall

15328

Females

4866

F18-39

4866

10K→15K

6.2 - 9.3 mi

Top 56%
×3stories
+67ft-78ft

Overall

14907

Females

4620

F18-39

4620

15K→20K

9.3 - 12.4 mi

Top 51%
×5stories
+106ft-86ft

Overall

13614

Females

3884

F18-39

3884

20K→Half

12.4 - 13.1 mi

Top 57%
×2stories
+19ft-37ft

Overall

15205

Females

4790

F18-39

4790

Half→25K

13.1 - 15.5 mi

Top 49%
×4stories
+66ft-88ft

Overall

12932

Females

3589

F18-39

3589

25K→30K

15.5 - 18.6 mi

Top 45%
×9stories
+181ft-148ft

Overall

11960

Females

3166

F18-39

3166

30K→20M

18.6 - 20.0 mi

Top 42%
×5stories
+64ft-50ft

Overall

11105

Females

2794

F18-39

2794

20M→21M

20.0 - 21.0 mi

Top 38%
×8stories
+106ft-24ft

Overall

10007

Females

2399

F18-39

2399

21M→35K

21.0 - 21.8 mi

Top 48%
×7stories
+17ft-86ft

Overall

12735

Females

3842

F18-39

3842

35K→23M

21.8 - 23.0 mi

Top 39%
×5stories
+23ft-63ft

Overall

10267

Females

2638

F18-39

2638

23M→24M

23.0 - 24.0 mi

Top 33%
×6stories
+12ft-82ft

Overall

8804

Females

2016

F18-39

2016

24M→40K

24.0 - 24.9 mi

Top 32%
×1story
+6ft-20ft

Overall

8437

Females

1927

F18-39

1927

40K→25.2M

24.9 - 25.2 mi

Top 31%
×1story
+13ft-16ft

Overall

8216

Females

1943

F18-39

1943

25.2M→Finish

25.2 - 26.2 mi

Top 30%
×2stories
+22ft-21ft

Overall

8019

Females

1849

F18-39

1849

Passing Analysis

Category:
Athletes Passed
3790
Passed By
371
Net Change
+3419
SegmentAthletes PassedPassed ByNet ChangeStart RankEnd Rank
Start → 5K----#16058
5K → 10K523152+371#16058#15687
10K → 15K34285+257#15687#15430
15K → 20K49718+479#15430#14951
20K → Half3335-2#14951#14953
Half → 25K33311+322#14953#14631
25K → 30K50111+490#14631#14141
30K → 20M2756+269#14141#13872
20M → 21M2684+264#13872#13608
21M → 35K8229+53#13608#13555
35K → 23M2367+229#13555#13326
23M → 24M2427+235#13326#13091
24M → 40K1852+183#13091#12908
40K → 25.2M701+69#12908#12839
25.2M → Finish2033+200#12839#12639
TOTALS3790371+3419
📊

Passing Visuals

Category:
Loading...

🔥Passing Intensity

Loading...

🔄Passing Circle

Loading...

🌊Position Flow

Loading...

🏃Race Lanes

Loading...

Upload your GPX file

Supports Garmin, Apple Watch, Polar, Suunto, COROS, Strava, and other apps

.gpx files up to 10MB

Export Track Data

Download your race performance as a GPX or TCX file to import into Strava, Garmin Connect, or other fitness apps.

Questions or issues regarding timing data?

If you notice any discrepancies in your timing data or have questions about your results, our support team can help.

Contact Race Support
Share Feedback

Public Race Data

Boston Athletic Association

Boston Athletic Association

Mika Timing

Mika Timing