Flashcards with Real Spaced Repetition

A study session, end to end

Pick a deck above — the counter shows due cards (scheduled reviews that are ready) and new cards (never shown). Press Study and the app deals a queue: due cards first, most overdue first, with new cards dealt in at a one-per-three-reviews ratio. A card shows its front; click it or press Space to flip, recall the answer honestly, then grade it 1 Again, 2 Hard, 3 Good or 4 Easy. Cards you fail come back a few positions later in the same session — the session isn’t done until the queue is empty, and the summary shows your recall rate, lapses and time.

The scheduler is real — and documented

This isn’t a “review it whenever” toy. Every card carries an ease factor (starts at 2.5, floor 1.3), a repetition count and an interval in days. Passing intervals run 1 day → 6 days → round(previous × ease), and every grade adjusts ease by a published formula: Again −0.32, Hard −0.14, Good ±0, Easy +0.10. It’s a variant of SM-2 — the algorithm SuperMemo published in the 1980s — adapted to four buttons, and it is honestly not Anki’s scheduler. The algorithm page has the full math, worked examples and the differences.

Decks are files on your device, not rows on our server

There is no account, no sync, and no server-side storage: each deck lives as a versioned record in your browser’s localStorage, which is why the app works offline once loaded. The trade is real — clearing site data wipes your decks — so every deck exports to a plain two-column CSV for backup or for moving into Anki, a spreadsheet, or another tool. The CSV notes cover the format and the Anki round-trip.

Make your own cards worth studying

The sample decks (Spanish essentials, world capitals) are there to be studied, but the real use is your own material: open a deck, add cards front/back, or import a CSV you already have. Cards take a small markdown subset (**bold**, *italic*, `code`). If your cards aren’t sticking, the problem is usually the cards, not the schedule — how to write good cards covers the minimum-information principle, and structuring study sessions covers pacing new cards against reviews.

Frequently asked questions

Is this the same algorithm Anki uses?

No — and we don't claim it is. FlashDeck runs a documented variant of SM-2, the scheduler Piotr Wozniak published for SuperMemo 2: ease factor starts at 2.5, intervals go 1 day → 6 days → ×ease, and a lapse resets the card to relearning. Anki's scheduler is a different SM-2 descendant with its own learning steps and modifiers. The exact math is on the algorithm page — you can check every number yourself.

Where are my decks stored? Can I lose them?

In your browser's localStorage, on this device, under versioned keys. Nothing is uploaded — there is no account and no server that could hold your cards. That also means clearing site data or switching browsers/devices loses the decks, so export a CSV backup for anything you can't afford to rewrite. The CSV page covers the format.

What do the four grade buttons actually do?

Again (key 1) is a lapse: the card's ease drops and it comes back later in the same session until you recall it. Hard (2), Good (3) and Easy (4) all pass the card to the same next rung — 1 day, then 6 days, then previous interval × ease — but they nudge the ease factor down, sideways or up, which changes how fast all future intervals grow. Honest grading is what makes the scheduler work; grade what actually happened, not what you wish happened.

How many new cards should I study per session?

The default deals up to 20 new cards per session, interleaved one per three reviews. That keeps tomorrow's review pile survivable: 20 new cards a day compounds into roughly 100–150 daily reviews within a couple of weeks. You can change the cap per deck (10 / 20 / 40 / all — up to 200) in the deck's Manage view — the session guide explains the trade-off.

Can I move decks between FlashDeck and Anki or a spreadsheet?

Yes, via CSV — two columns, front,back. Export any deck to CSV from its Manage view; import a CSV from the deck list or into an open deck. Anki's "Notes in Plain Text" export can be trimmed to the same two columns in any spreadsheet app. Scheduling data doesn't travel in plain CSV — cards arrive as new — and that's normal for every app. Details: CSV & Anki notes.

Does it work on my phone?

Yes — the whole app is one static page. Tap the card to flip, tap a grade button, or swipe left for Again and right for Good once the card is flipped. Everything the desktop keyboard can do (Space to flip, keys 1–4 to grade) has a touch equivalent.

Can I use markdown or images in cards?

A small markdown subset works on card faces: **bold**, *italic*, `code`, and line breaks. Images aren't supported — the deck format is deliberately text-only so CSV export stays lossless.