SRRL

Education

Spaced Repetition Review Load Calculator

Translate the entered learning calendar into productive review capacity and compare it with new, scheduled, repeated, and buffered workload.

New items introduced per dayExpected review events per new item in horizonExisting due reviews per dayAverage minutes per reviewMinutes available for review per dayUsable study-time share (%)Buffer for missed or difficult days (%)Current overdue-review backlogDays planned to clear backlog

Steady-state reviews created by new items-

Daily backlog-clearance reviews-

Base daily review events-

Review events after missed-day buffer-

Productive review minutes available-

Reviews supportable per day-

Capacity minus buffered review load-

Minutes required for buffered review load-

New items supportable after existing and backlog reviews-

Decision view

New learning, review waves and daily queue capacity

New learning, review waves and daily queue capacityNew items create future review events; existing due work and backlog clearance are buffered before comparison with productive review capacity.

Exact scenario comparisonNew items introduced per day changes while all other entered assumptions remain constant.

New items introduced per day	Steady-state reviews created by new items	Daily backlog-clearance reviews	Base daily review events	Review events after missed-day buffer	Productive review minutes available	Reviews supportable per day	Capacity minus buffered review load	Minutes required for buffered review load	New items supportable after existing and backlog reviews

Period-by-period detail

spaced-repetition review weekly allocation

The weekly table converts the entered daily schedule into cumulative productive hours, completed workload, required workload and remaining margin.

How to use Spaced Repetition Review Load Calculator

Measure actual cards or items completed per focused hour.
Separate new-item limits from due-review limits.
Add a missed-day buffer because deferred reviews return later.

Calculator guide

Understanding Spaced Repetition Review Load Calculator

Spaced-repetition workload grows from new material, review intervals, recall quality, lapse rate, daily capacity, and the buffer needed for volatile review queues.

New items create future reviews Today's additions affect later workload.

Backlogs compound Deferred reviews return alongside new due items.

Capacity needs slack A full queue leaves no room for variability.

Calculation method

How the calculation works

Convert new learning into its future steady-state review burden, add existing due work and backlog clearance, then compare buffered review time with productive daily capacity. Convert available study time to productive capacity, add review and missed-day overhead to the core workload, and calculate daily minutes and coverage.

Detailed calculation process

Reconcile review demand with productive queue capacity

The default plans 420 learning units across 14 weeks, six study days per week, 110 focused minutes per day, 78% productive time, 4.5 units per productive hour, 18% review overhead, and a 12% disruption buffer.

General formula: D = wd; H_g = Dm/60; H_p = H_g e; C = H_p v; R = Wq; B = (W+R)b; T = W+R+B; M = C-T; H_r = T/v; m_r = 60H_r/(De); coverage = 100C/T New learning creates review demand, and both together create the buffer basis. Available focused time is reduced to productive time before it is converted to queue capacity.

What each symbol means

W, w, d, D Core learning units, available weeks, study days per week, and scheduled study days.

m, e, H_p Minutes per day, productive-time rate, and productive hours.

v, C Units processed per productive hour and total capacity.

q, R, b, B, T Review rate, review units, buffer rate, buffer units, and total planned queue.

Worked substitution with the default inputs

1. Calculate productive capacity: 14 x 6 = 84 days; 84 x 110 / 60 = 154 gross hours; 154 x 78% = 120.12 productive hours Interruptions and nonproductive study time are removed before estimating completed reviews.

2. Convert capacity to units: 120.12 x 4.5 = 540.54 units This is the modeled queue capacity across the whole calendar.

3. Build the review queue: 420 x 18% = 75.6 review units; (420 + 75.6) x 12% = 59.472 buffer units; total = 555.072 units The buffer covers disruption across both new and scheduled review work.

4. Reconcile the plan: 540.54 - 555.072 = -14.532 units; coverage = 540.54 / 555.072 x 100 = 97.38%; required = 112.96 focused min/day The default queue slightly exceeds modeled capacity, so new-item creation or daily time should be adjusted.

The default review plan covers about 97.4% of the buffered queue and is short by roughly 14.5 workload units.

Review wave calendar

Watch new items return as scheduled review waves

The calendar distinguishes new learning, due reviews, lapses, backlog, and productive daily capacity.

New-item row Items introduced today.

Review waves Future scheduled retrieval.

Lapse return Failed items reentering sooner.

Capacity line Daily review limit.

Worked situations

Practical examples

Adding too many new cards creates a delayed review wave.
Low recall raises lapses and repeated workload.
A skipped weekend can produce a Monday queue larger than daily capacity.

Better inputs

Useful tips

Stabilize due reviews before increasing new items.
Use rolling seven-day averages.
Suspend or reschedule low-priority material rather than repeatedly missing the queue.

Before relying on the result

Limitations and common mistakes

The model uses average review productivity and overhead.
Item difficulty, scheduler algorithm, interval distribution, relearning steps, fatigue, and recall probability are simplified.
Coverage does not measure durable knowledge.

Reference

Key terms

Review queue: Items scheduled or overdue for retrieval practice.
Lapse: Previously learned item answered incorrectly and returned to relearning.
Maturity: Item with a longer established review interval.

Important note

The queue calculation uses the entered review workload, revision overhead, productive minutes, and buffer. Actual recall strength, item difficulty, lapse behavior, scheduler algorithms, and missed sessions can change the review load.

Frequently asked questions

Should new cards be stopped during backlog?

Often reduce or pause them until due reviews are stable.

Does more daily time always solve the queue?

Not if new-item creation and lapse rates continue exceeding capacity.

Does this predict recall?

No.