Vastu Tool Accuracy: What Each Kind of Tool Can Actually Know About Your Home
Compass apps, form calculators, floor-plan analysers and desktop software answer different questions. What each one is given decides what it can know - and what an accuracy claim can mean.
Author - Vaastu AI Editorial
A Vastu tool can only know what you hand it. A compass app is given a bearing, so it can tell you which way you are facing and nothing about your rooms. A form calculator is given the room and the direction it sits in — which means you have already answered the hard part yourself, and it is restating a table back to you. A floor-plan analyser is given the plan, so it can see where rooms sit relative to each other, but it still cannot know which way is north unless you tell it. Desktop software is given whatever you draw. None of them can see what is outside your walls, and none of them has a ground truth to be accurate against. So before you weigh one tool's verdict against another's, it is worth being precise about what each was actually in a position to know.
Our bias, stated plainly: we make one of these tools. What follows describes categories rather than ranking brands, and every number we quote about our own scoring is published below so you can check it.
What each kind of tool is given
| Kind of tool | What you supply | What it can know | What it cannot |
|---|---|---|---|
| Compass app | A phone bearing | The facing direction, and how reliable your phone's magnetometer is | Anything about your layout |
| Form calculator | "Kitchen — south-east", room by room | Whether each answer you typed matches its table | Whether you placed the rooms correctly, or where they sit relative to each other |
| Floor-plan analyser | An image or PDF of the plan, plus north | Which zone each room falls in, and how the rooms sit together | North, unless you confirm it; anything not drawn on the plan |
| Desktop software | A layout you draw yourself | Whatever you modelled, in detail | Whether your drawing matches the built flat |
| Human consultant | A site visit | Slope, surroundings, materials, water, the things no file contains | — |
The row that matters most for anyone comparing tools online is the second. A form calculator that asks you to select "kitchen" and then "north-east" has been handed the conclusion. Its output is a lookup, and its quality is the quality of its table — which is worth knowing, but it is not an analysis of your home.
What "accuracy" can and cannot mean here
Several tools in this category advertise an accuracy percentage, usually framed as agreement with expert review. Treat those figures carefully, for two reasons that have nothing to do with the vendors' honesty.
First, the figure is never published with the test set. A percentage with no stated sample, no scoring rule and no way to reproduce it is a marketing number, not a measurement — ours included, which is why we do not print one.
Second, and more fundamental: Vastu has no single ground truth to be accurate against. The classical texts differ, regional conventions differ, and two qualified practitioners can look at the same plan and weight it differently. A tool cannot be 92% correct about a question the field itself answers more than one way. What a tool can be is explicit — it can tell you the table it is using, so you can see where it stands and disagree with it if you want to.
A better test than a percentage
Ask any tool these five questions, in this order. They are answerable from a page, they take about two minutes, and they discriminate far better than an accuracy claim.
- Does it tell you which direction it thinks is north, and let you correct it? Get north wrong and every other answer is confidently wrong. This is the single largest source of bad Vastu output, and it is the reason our check stops and asks you to confirm north and the room labels before it computes anything.
- Does it publish the direction-by-room table it scores on? If you cannot see the table, you cannot check the verdict.
- Does it say which rooms carry the weight? A tool that treats the pooja shelf and the main entrance as equal contributors is telling you something misleading about what to fix first.
- Does it separate "bad" from "unfixable"? These are different questions and most remedy content merges them.
- Does it say what it cannot see? Slope, the plot's surroundings, materials, what is above or below a room — no tool reading a floor plan sees any of it.
The tables ours runs on
Here is what we score with, so questions 2, 3 and 4 are answered for our own tool rather than asked of everyone else's.
The bands. A placement scores 0–100 and reads as ideal at 90 or above, good from 70 to 89, acceptable from 50 to 69, and avoid below 50.
The weights. Not every room counts the same. The main entrance carries 18% of the verdict, the kitchen 16%, the master bedroom 13%, toilets 12%, the pooja space 9%, the living room 8%, a secondary bedroom 7%, a staircase 5%, dining 4%, a store 3%, and everything else 2% each.
The recovery split. This is the part that separates "bad" from "unfixable". Rooms anchored to plumbing or structure recover only about half of a bad placement's deficit without construction — toilets and kitchens about 45%, entrances, staircases and garages about 50%. Everything else recovers around 85%. Applied to real cells:
| Placement | Score now | Verdict | Realistically reaches | Verdict then |
|---|---|---|---|---|
| Main door, south-west | 25 | avoid | ~63 | acceptable |
| Main door, south | 40 | avoid | 70 | good |
| Kitchen, north-east | 15 | avoid | ~53 | acceptable |
| Toilet, north-east | 15 | avoid | ~53 | acceptable |
| Master bedroom, north-east | 25 | avoid | ~89 | good |
The last row is the point of publishing any of this. A north-east master bedroom and a north-east toilet both start in the avoid band at the same score, and they are not remotely the same problem: one is fixed by deciding a different room is the master, the other needs plumbing. No accuracy percentage would ever have told you that.
Where to go from here
If you want the category-by-category version — what free calculators, AI analysers, desktop software, chat AI and human consultants each cost and each leave out — that is laid out on our Vastu tools comparison page, including where we fit. If your immediate problem is that you do not trust your phone's compass reading on a plan, the online Vastu compass is free and needs no app. And if you want a second opinion on a verdict some other tool gave you, the honest way to get one is to have a tool look at the plan itself: upload your floor plan for a free Vastu check, confirm north and the room labels, and see the zone every room falls in with a score. The paid detailed report adds the room-by-room analysis and tiered remedies.
For the placement side of this in a flat specifically, the 2BHK and 3BHK room-by-room checklist puts the same weights to work in the order a buyer should actually check them.