Calculators tools

Practical calculators for LLM context windows, API costs, VRAM estimates and home mortgages.

Context Window Calculator Convert between tokens, English words and book pages, with presets for GPT, Claude and Gemini context windows. Free, browser-based. LLM API Cost Calculator Estimate monthly LLM API spend: pick a model, enter input/output tokens and request volume. Prices for GPT, Claude, Gemini. Free, private. LLM VRAM Calculator Estimate GPU VRAM for running an LLM: parameters × quantization (FP16/INT8/Q4/Q2) plus context KV cache. Free, browser-based. Mortgage Calculator Calculate monthly mortgage payments, total interest and amortization from loan amount, rate and term, with a balance chart. Free, private. Date Duration Calculator Calculate the duration between two dates in days, weeks, months and working days. Free browser-based date difference calculator. Aspect Ratio Calculator Calculate new dimensions by aspect ratio: 16:9, 4:3, 1:1, 9:16, 21:9 presets with width or height lock. Free, instant, browser-based.