Mind Forge (bdjydl.com) is a small set of free tools that turn "work it out by hand again, then go looking it up again" into "fill in a few boxes, press one button". The site currently holds 24 tools. The site is about: Brain training that respects your time and your brain. Everything runs in your browser: no sign-up, no login, nothing you type is uploaded.
Three groups, mostly. First, people who already have the numbers and simply do not want to re-key them into a calculator every time - someone drafting a budget, or an operator who needs a rough figure to align with a colleague in the next ten minutes. Second, people preparing for an exam, an interview, an application, or a document they have to submit, who want a way to test "what if I change this number". Third, teachers, coaches, and leads who need to explain a rule of thumb rather than hand over an answer.
Whatever group you are in, the position of this site is the same: it puts the reasoning in front of you instead of making the decision for you.What a tool returns is a reference value computed from the inputs you supplied. Before you act on it, you still check it against the source material, the situation on the ground, or the official guidance.
Every tool has an explicit, reproducible method: what goes in, what formula is applied, what comes out. The logic is not hidden - the full calculation is visible in the page source. That buys two things. The result can be checked by somebody else, and if you think a number is wrong you can follow the formula to the step whose assumption does not hold, instead of choosing between trusting it and not trusting it.
Because all of it runs locally, the amounts, durations and ratios you type never leave the device. That matters most for the inputs that describe your own situation.
Every page has a floor it has to clear: enough body copy that it is not just a form with a button; at least four questions answered, with the three things that actually decide whether a tool is used well written down - how to use it, where people go wrong, and when it does not apply. Where a page states a specific number, a price, a fee or a rule, it says "check the official source" and gives you a route to check it yourself, rather than inventing a number that looks plausible.
Instructions, the verdict labels and the computed result are kept separate. Instructions tell you how to use the tool, the labels qualify what the number means, and the result is the number. Mixing those three is how a conclusion drawn under one set of conditions quietly turns into a general rule, and it is a mistake we keep going back and fixing.
It does not give medical diagnoses, medication doses, legal opinions or investment advice. The tools help you frame a question better or get the arithmetic right; the conclusion still comes from a qualified professional or from the official source. For outdoor, diving, wildlife, protected-area and border situations, the site provides safety checklists and official contacts only - it does not provide decompression tables, does not certify any depth or weather as safe, and does not explain how to work around regulations.
Tool pages get reviewed: does the logic still hold, is the reference data still current, are the stated limits still true. When the premises of a tool change, the wording on the page changes too, rather than leaving a stale conclusion in place. If a page does not match what you are seeing in practice, the contact details in the footer are the way to tell us.
- Flicker Change-Blindness Test - Two nearly-identical scenes alternate. A blank flash separates them. Find the change before attention drifts.
- 4-Choice Reaction Time (Hick's Law) - Press the matching arrow key. Per-choice histograms and Hick's rate constant estimation.
- Chunking Trainer - Memorize phone-number-like digit strings. The tool reveals how you spontaneously chunk them, helping you under
- Cognitive Reflection Task (CRT) - Three (plus three bonus) classic trick problems that test whether you answer intuitively or stop and reflect.
- Corsi Block-Tapping — Forward & Reverse - Reproduce growing sequences on a 3x3 grid. Tracks your forward and reverse visuospatial span separately — the
- Digit Span — Forward & Backward - Listen to growing digit sequences and recall them forward or backward. With adjustable audio presentation rate
- Adaptive Dual N-Back - A precise, adaptive Dual N-Back trainer that adjusts level based on per-modal accuracy. Tracks hits, misses, f
- Calibrated Estimation Game - Estimate quantities (count, distance, weight, area). We score calibration — whether your confidence matches yo
- Face-Name & Letter Memory - Recognize abstract face-like patterns after a delay. Tests associative visual memory using same/different rath
- Go / No-Go with Auditory Cues - Press for go stimuli, withhold for no-go. We split commission errors (impulsive false presses) from omission e
- Adaptive Math Reflex - Quick arithmetic with adaptive difficulty based on rolling accuracy and RT. Tracks per-operation (addition/sub
- Method-of-Loci Practice - Place items along a familiar route, then recall them. Built-in loci hints for beginners and route-rehearsal fe
- Shepard Mental Rotation - Judge if two 3D-style shapes match after rotation. We measure your personal rotation-rate slope — how much ext
- Pattern-Sequence Induction - Watch colored shapes follow hidden rules. Predict the next. Rule complexity grows — and we plot the difficulty
- Prospective Memory Trainer - Embedded-target detection: while doing one task, press a special key when you see a specific cue. Event-based
- Multi-Task Reaction Cost - Two simultaneous choice tasks. Compare dual-task cost to single-task baseline, plotted per block.
- Reading-Span Task - Read sentences and remember the final word of each. Partial-credit and serial-position scoring reveal how work
- Wisconsin-Style Card Sort - Sort cards by a hidden rule (color, shape, count). The rule changes without warning. Perseveration rate and tr
- Schulte Grid + Heatmap - Find numbers 1-25 in order on a Schulte grid, with a per-cell time heatmap that visualizes your scan pattern.
- Multi-Language Stroop Trainer - A color-word Stroop interference test across multiple languages, with reaction-time histogram and an in-sessio
- Sustained Attention (AX-CPT) - Watch for a specific cue-then-target sequence (AX-CPT). Tracks time-on-task drift to reveal vigilance decay.
- Trail Making Test (TMT-A & TMT-B) - Connect numbered dots (TMT-A), then alternate between letters and numbers (TMT-B). The ratio (B time / A time)
- Conjunction Visual Search - Find a target among distractors. We vary the search type (feature vs. conjunction) and set size, then fit your
- Word-List Recall with Proactive Interference - Memorize word lists A, B, C in sequence. We measure proactive interference — how much an earlier list hurts re
Do the tools need an account or a payment?
No. Every tool on Mind Forge is free, needs no account, and works before you type anything personal. The numbers you enter are used by the calculation on the current page and are gone when you reload.
Can I treat the output as a final answer?
Not on its own. A tool returns a magnitude under the conditions you typed in. It does not include what it costs to act, what might change while you act, or how the other side behaves. Before spending money, signing, or promising something to a third party, check the result against the source material and the official position.
What is the most reliable way to use these tools?
Follow the order given in the usage section: get your figures onto the same basis first, fill in one field at a time, then calculate. Checking that every unit matches the thing you are actually measuring catches more wrong answers than any other habit, and it takes about ten seconds.
My number does not match what I expected. What should I check?
Three things: that the units agree, that you have not left an optional field blank and accepted its default, and that you recalculated after editing an input. If all three are fine, the likely explanation is that your basis differs from the one the tool assumes - the limitations section on each tool page says what it covers.
Will the pages stay available?
We try to keep them, but the premises of a tool, the reference data and the outside world all move. Pages get reviewed and corrected as that happens. If you need to keep a result long term, take a screenshot and record the inputs you used.
This page describes what the tools on this site are built to do. A common mistake is to read a short explanation and treat it as an official specification 鈥?it is not. Every tool here is a calculation aid: it works from the numbers you type in, and it cannot verify whether those numbers are correct, current, or appropriate for your situation.
Where this stops: the tools give you a number and the reasoning behind it. They do not replace professional advice, and they do not know anything about your specific case. Where a decision carries legal, financial, safety or health consequences, check the relevant official source before acting on anything you read here.