Detour Budget Planner
Compare proposed stops by estimated extra distance, time, cost and visit duration.
Try an example: Try an example
How it works
Enter start, destination and candidate stop coordinates. Estimate extra kilometres, minutes and cost from a published road circuity factor, or route on your own OpenStreetMap extract or GPX file. Nothing is sent to a routing service.
- Estimate (default): WGS84 geodesic distance (Karney 2013) between every pair of points, multiplied by a road circuity factor. Published factors: 1.46 for Europe (Ballou, Rahardja & Sakai 2002, Transportation Research Part A 36(9)), 1.42 for the United States (Boscoe, Henry & Zdeb 2012, The Professional Geographer 64(2)) and a median of 1.25 for long road trips between continental European countries (Networks and Spatial Economics 2026). Short trips, rivers, lakes and mountains are often more circuitous; enter your own factor when you know better. The factors were measured on road networks; walking and cycling networks can differ.
- Precise mode (optional): paste or open your own OpenStreetMap extract (OSM XML or GeoJSON with OSM tags) or a GPX file. Cartograph’s road graph and Dijkstra shortest paths give network distances. Cars use public roads and respect one-way streets; bikes and walkers follow Cartograph’s access rules. Each point is joined to the nearest node of a usable way within 1 km by a straight connector. GPX lines are treated as two-way ways. Map data stays with you: no routing, geocoding or map-tile service is contacted.
- Time = distance ÷ average speed (editable; defaults 60 km/h by car, 15 km/h by bike and 5 km/h on foot are assumptions, not measured). Cost = extra kilometres × your cost per kilometre. No live traffic, speed limits, turn restrictions or elevation.
- Compare stops individually, or search all ordered subsets of up to three stops. The suggested itinerary maximizes the number of visits within the budget, then minimizes added time. Optional opening/closing times are your own same-day assumptions; a closing time earlier than opening means the following day. Waiting and visits count toward the extra-time budget.
Part of Hearth
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Hearth Home & travel planner
Plan meals, chores, home care, moves, trips and good days for your household in one place.
How to use the Detour Budget Planner
Check which stops fit into your extra-time budget on a trip, with estimated extra kilometres, minutes and cost, or exact distances on your own map.
What it is for
On the way from A to B you could stop for a break, a museum or a viewpoint, but how much longer does the trip get, and does it still fit your plans? This tool compares up to ten candidate stops against an extra-time budget. Visit time and waiting for an opening time count towards that budget. It also suggests the best combination of up to three stops.
Nothing is sent to a routing, address-search or map service. By default the tool estimates road distance: the shortest distance over the Earth's surface multiplied by a published circuity factor, because roads are never straight. If you want real network distances, open your own OpenStreetMap extract or a GPX file and the planner finds shortest paths on it. It does not know live traffic, speed limits or whether a place is really open.
Worked example
The default inputs: start at 48.89, 8.7, destination at 48.78, 9.18, travelling by car at the default 60 km/h with the Europe factor 1.46, 0.30 per extra kilometre, a 45-minute budget and departure at 09:00. Two stops: a 15-minute Proposed break at 48.85, 8.95 and a 45-minute Museum visit at 48.8, 8.85.
The result: "Estimate: 1 of 2 stops fit; suggested itinerary: 1 visit." The direct trip is estimated at 54.46 km and 54.46 minutes.
| Stop | Added km | Added minutes | Added cost | Fits |
|---|---|---|---|---|
| Proposed break | 0.25 | 15.25 | 0.07 | Yes |
| Museum visit | 2.81 | 47.82 | 0.84 | No |
The break lies almost on the way, so it costs a quarter of a kilometre plus its 15 minutes. The museum adds only 2.81 km, but its 45-minute visit pushes it over the budget. With a 90-minute budget and Maximum stops set to 2, both fit: museum first (09:22–10:07), then the break (10:20–10:35), arriving at 11:02 after 7.87 extra km and 67.87 extra minutes.
How to read the result
- Direct trip (km / minutes) is the baseline without any stop. Every added value is measured against it.
- Individual stops compares each stop on its own: added kilometres, added minutes (driving, waiting and the visit), added cost, arrival and departure time, and whether it fits both the budget and the opening times you entered.
- Suggested itinerary is the best combination: as many visits as fit, then the least added time.
- Method tells you whether the numbers are an estimate or come from your road network. In network mode, Connection to the road network shows how far each point is from the nearest node of a usable way.
Tips and common mistakes
- Treat estimates as estimates. Short trips, rivers, lakes and mountains make roads more roundabout; if you know your area, enter your own factor.
- Set the average speed to how you really travel. With the default 15 km/h by bike, the same trip takes 217.84 minutes instead of 54.46.
- For exact distances, crop your OpenStreetMap extract to the trip area. One-way streets apply to cars and bikes, and motorways only to cars.
- Keep points close to roads in network mode: points more than 1 km from the network are rejected.
- Enter opening and closing times from the venue itself. Waiting until a stop opens counts towards your budget.
FAQ
Why doesn't the tool look up addresses or calculate routes online?
Your trip stays with you: no coordinates are sent to a routing or geocoding provider. Copy coordinates from any map you like.
How accurate is the estimate?
It depends on the region. The published factors are averages over many trips, so a single trip can differ noticeably. Use network mode when the difference matters.
Can I use a GPX file instead of a map extract?
Yes. Tracks and routes become two-way ways, but they only connect where track points share exactly the same coordinates.
What does the cost include?
Only extra kilometres times your cost per kilometre. Parking, tickets or tolls are not included.
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For scripts and AI agents
- JSON API:
POST https://hearthdetourbudget.usefulweb.app/api/v1/calculate(same calculation as this page) - Interface description: OpenAPI 3.1 · AI guide: llms.txt
- MCP server (Streamable HTTP):
https://hearthdetourbudget.usefulweb.app/mcp· tool namehearth_detour_budget
Example request
curl -s -X POST https://hearthdetourbudget.usefulweb.app/api/v1/calculate \
-H 'content-type: application/json' \
-d '{}'