42cal logo
42cal
MarathonOS

Run Your Next Marathon.

Free Training Tools

View all →

Pace Calculator

Calculate splits, finish time, and pace for any distance.

Race Time Predictor

Predict marathon, half, and 10K times from a recent race.

BQ Calculator

Check if your time qualifies for the Boston Marathon.

Training Pace Zones

Get your VDOT and five training zones from Jack Daniels.

Race Day Fuel Planner

Plan carbs, hydration, and electrolytes for race day.

Course Difficulty Analyzer

Score any course on elevation, altitude, heat, and more.

MarathonOS

An iOS app for marathon training. Track runs, follow a plan, prepare for race day.

Join waitlist →

42Cal · MarathonOS

© 2025 42Cal. All rights reserved.

Tools

Your Race HistoryRace Time PredictorCompare RacesBQ CalculatorPace CalculatorTraining PacesDifficulty AnalyzerFuel PlannerAll tools

Explore

BlogLocationsDistancesCountries
SupportPrivacyTermsFeedback: biz@42cal.com

    Featured Races

    Oct 4, 2026Marathon (26.2 miles / 42.2 km)
    The Lowdown

    Often dubbed “The Most Beautiful Urban Marathon in America,” the Twin Cities Marathon delivers on scenery​. The race is a one-way route connecting Minnesota’s two largest cities: it starts in downtown Minneapolis (near U.S. Bank Stadium) and finishes at the State Capitol in St. Paul​. Along the way, the course showcases fall colors and city lakes – you’ll run past sparkling Lake of the Isles, Bde Maka Ska, Lake Harriet, and along the Mississippi River. Historic Summit Avenue in St. Paul, lined with autumn trees and stately homes, comprises the final miles​. The terrain is mostly flat to gently rolling; the biggest challenge is an extended gradual uphill from about mile 20 to 23 as you climb from river level up to the finish at the Capitol (roughly a 200-foot gain, which feels significant late-race)​. Overall, many runners find Twin Cities fast – there’s enough downhill and flat early on to offset the late hills. And the visuals are stunning throughout, from urban skylines to natural vistas.

    Medtronic Twin Cities Marathon

    Minneapolis , MN, United States

    Oct 3, 2026Marathon (26.2 miles / 42.2 km)
    30m Elevation

    MALMÖ MARATHON

    Malmö, Sweden

    Article

    A Runner's Holiday Survival Guide: Stay Training Ready

    “Obstacles aren't in the way; they are the way.”

    — Unknown

    Nov 29, 2026Marathon (26.2 miles / 42.2 km)
    10K Runners

    Estra Firenze Marathon

    Florence, Italy

    Oct 18, 2026Marathon (26.2 miles / 42.2 km)
    Mild Weather

    IMT Des Moines Marathon

    Des Moines, IA, United States

    Oct 11, 2026Marathon (26.2 miles / 42.2 km)
    30K Runners

    SPAR Budapest Marathon

    Pázmány Péter Promenade, Hungary

    3K+
    Miles of Racing
    Ready to explore
    Oct 25, 2026Marathon (26.2 miles / 42.2 km)
    Cool Weather

    Swiss City Marathon

    Lucerne, Switzerland

    Article

    Indoor Track Running: Your Weather-Proof Training Alternative

    Sep 27, 2026Marathon (26.2 miles / 42.2 km)
    13K Runners

    Nationale-Nederlanden Warsaw Marathon

    Warsaw, Poland

    “Run when you can, walk if you have to, crawl if you must; just never give up.”

    — Dean Karnazes

    Oct 25, 2026Marathon (26.2 miles / 42.2 km)
    7/10 CR

    Wizz Air Venice Marathon

    Venice, Italy

    Oct 18, 2026Marathon (26.2 miles / 42.2 km)
    7/10 CR

    TUI PALMA MARATHON MALLORCA

    Palma de Mallorca, Spain

    Oct 25, 2026Marathon (26.2 miles / 42.2 km)
    The Lowdown

    The Dresden Marathon, first held in 1999, has grown into one of Germany’s most celebrated autumn road races, combining competitive marathon tradition with a festival-like city atmosphere. Set on 25 October 2026, the race draws both international runners and enthusiastic local crowds, celebrating Dresden’s post-reunification sporting and cultural revival. Over the years it has become known for its well-organized logistics, strong community support, and reliable October weather that often produces fast race conditions for those chasing personal bests or qualifying standards. The flat, fast course threads through Dresden’s historic heart and along the scenic Elbe River, passing icons such as the Frauenkirche, Semperoper, Zwinger and the baroque terraces of the Brühl’s Terrace, before offering long, tree-lined stretches on the Elbe meadows and views of the riverside palaces and bridges. Runners experience a mix of cobbled historic sections and smooth, wide boulevards, with numerous live music stations and cheering points that create a lively, supportive atmosphere. The event is AIMS-certified and German national federation (DLV) certified, and the course is routinely accepted for major marathon qualification purposes, making it a popular choice for runners seeking Boston-qualifying times.

    Dresden Marathon

    Dresden, Germany